Transition of Patients Established on Long-term Treatment with Transmucosal Buprenorphine
Patients established on long-term treatment with transmucosal buprenorphine (8-24 mg/day) and whose disease symptoms are controlled may be directly transitioned to SUBLOCADE [seeTable 1]. At steady-state, buprenorphine plasma concentrations achieved with 100-mg monthly dosing are contained within the range obtained with transmucosal treatment; peak concentrations with SUBLOCADE may be lower, while average and trough concentrations may be higher. Potential differences in steady state levels need to be taken into consideration when transitioning a patient established on long term treatment with transmucosal buprenorphine to SUBLOCADE [see Clinical Pharmacology (12.3),Table 7].
Table 1 Transition of Patients Established on Long-term Treatment with Transmucosal Buprenorphine Whose Disease Symptoms are Controlled
|
| Transmucosal Buprenorphine Doses | SUBLOCADE |
| Injection #1 | Injection #2 | Maintenance Dose |
| 8 – 18 mg/day
| 300 mg
| 100 mg*
| 100 mg
|
| 20 – 24 mg/day
| 300 mg
| 300 mg
| 100 mg
|
Patient Access to Naloxone for the Emergency Treatment of Opioid Overdose
Discuss the availability of naloxone for the emergency treatment of opioid overdose with the patient and caregiver.
Because patients being treated for opioid use disorder have the potential for relapse, putting them at risk for opioid overdose, strongly consider prescribing naloxone for the emergency treatment of opioid overdose, both when initiating and renewing treatment with SUBLOCADE. Also consider prescribing naloxone if the patient has household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose [see Dosage and Administration (2.3)].
Advise patients and caregivers that naloxone may also be administered for a known or suspected overdose with buprenorphine itself. Higher than normal doses and repeated administration of naloxone may be necessary due to the long duration of action of buprenorphine and its affinity for the mu-opioid receptor [see Overdosage (10)].
Inform patients and caregivers of their options for obtaining naloxone as permitted by individual state naloxone dispensing and prescribing requirements or guidelines (e.g., by prescription, directly from a pharmacist, or as part of a community-based program).
Educate patients and caregivers on how to recognize respiratory depression and, if naloxone is prescribed, how to treat with naloxone. Emphasize the importance of calling 911 or getting emergency medical help, even if naloxone is administered [see Patient Counseling Information (17)].
Longer-term experience
In an interim analysis of the ongoing open-label long-term safety study (13-0003), safety was evaluated for up to 12 injections over the course of a year (see Table 2). Adverse events were reported for 432 of 669 subjects during the treatment period. The overall adverse event profile was similar to the double-blind trial described above.
Risk Summary
The data on use of buprenorphine, the active ingredient in SUBLOCADE, in pregnancy, are limited; however, these data do not indicate an increased risk of major malformations specifically due to buprenorphine exposure. There are limited data from randomized clinical trials in women maintained on buprenorphine that were not designed appropriately to assess the risk of major malformations [see Human Data].
Observational studies have reported congenital malformations among buprenorphine‐exposed pregnancies, but were also not designed appropriately to assess the risk of congenital malformations specifically due to buprenorphine exposure [see Human Data].
In published animal reproduction studies with NMP, an excipient in SUBLOCADE, preimplantation losses, delayed ossification, reduced fetal weight, developmental delays and reduced cognitive function were reported at doses equivalent to the doses of NMP via SUBLOCADE. Decreased pup survival at 2 times the dose of NMP and malformation and postimplantation losses were reported at 3 times the dose of NMP via SUBLOCADE. In animal reproduction studies with SUBLOCADE, SUBLOCADE administered subcutaneously to pregnant rats and rabbits during the period of organogenesis at a buprenorphine dose equivalent to 38 and 15 times, respectively, the maximum recommended human dose (MRHD) of 300 mg caused embryolethality, which appeared to be attributable primarily to the SUBLOCADE vehicle. In addition, reduced fetal body weights, increased visceral malformations and skeletal malformations were observed in rats and rabbits at a buprenorphine dose equivalent to 38 and 15 times, respectively, the MRHD. These effects were also observed with the SUBLOCADE vehicle alone, but the skeletal and visceral malformations in rat appear at least partially attributable to buprenorphine [see Animal Data]. Based on animal data, advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
SUBLOCADE should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Clinical Considerations
Disease-associated maternal and embryo-fetal risk
Untreated opioid addiction in pregnancy is associated with adverse obstetrical outcomes such as low birth weight, preterm birth, and fetal death. In addition, untreated opioid addiction often results in continued or relapsing illicit opioid use.
Fetal/neonatal adverse reactions
Neonatal opioid withdrawal syndrome may occur in newborn infants of mothers who are receiving treatment with SUBLOCADE.
Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and/or failure to gain weight. Signs of neonatal withdrawal usually occur in the first days after birth. The duration and severity of neonatal opioid withdrawal syndrome may vary. Observe newborns for signs of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings and Precautions (5.7)].
Labor or Delivery
Opioid-dependent women on buprenorphine maintenance therapy may require additional analgesia during labor. As with all opioids, use of buprenorphine prior to delivery may result in respiratory depression in the newborn. Closely monitor neonates for signs of respiratory depression. An opioid antagonist such as naloxone should be available for reversal of opioid induced respiratory depression in the neonate.
Data
Human Data
Studies have been conducted to evaluate neonatal outcomes in women exposed to buprenorphine during pregnancy. Limited data on malformations from trials, observational studies, case series, and case reports on buprenorphine use in pregnancy do not indicate an increased risk of major malformations specifically due to buprenorphine. Pregnancy in an opioid dependent woman poses challenges to treating physicians and potential hazards for the fetus including control of illicit drug, nicotine and alcohol use, infections, premature birth, abortion, low birth weight, toxaemia, third trimester bleeding, malpresentation, puerperal morbidity, fetal distress, meconium aspiration, narcotic withdrawal, postnatal growth deficiency, microcephaly, (neuro-) developmental disorders and increased neonatal mortality.
A multicenter, double-blind, double-dummy, flexible-dose study in 175 pregnant women [Maternal Opioid Treatment: Human Experimental Research (MOTHER)] was conducted to study outcomes in neonates born to mothers using methadone or buprenorphine, including the number of neonates requiring treatment for NOWS, the Peak NOWS score, the total amount of morphine needed to treat NOWS, the length of hospital stay for neonates, and neonatal head circumference. The authors found that 18% of pregnant women in the methadone group and 33% in the buprenorphine group discontinued treatment over the course of the pregnancy. They reported no significant difference in the incidence of NOWS, but in the prenatally buprenorphine-exposed condition, the duration of treatment for NOWS was shorter, duration of hospital stays were shorter and the amount of morphine required was significantly less; however, methodological concerns limit the conclusions that may be made.
Animal Data
Preimplantation losses, delayed ossification and reduced fetal body weights were reported in published studies following treatment of pregnant rats during organogenesis with NMP, an excipient in SUBLOCADE, via inhalation at approximately equivalent doses of NMP delivered by SUBLOCADE. Fetal malformations and resorptions have also been reported following oral administration of 3 times the MDD of NMP delivered by SUBLOCADE at the MDD based on a body surface area comparison.
Post-implantation loss and increased cardiovascular and skull malformations were demonstrated in pregnant rabbits administered oral NMP, an excipient in SUBLOCADE, at doses 3.2 times the human MDD of NMP via SUBLOCADE in the absence of maternal toxicity. No adverse effects were reported at an oral dose equivalent to the MDD via SUBLOCADE based on a body surface area comparison.
Decreased pup survival was noted following oral treatment of pregnant rats prior to and during gestation and lactation with NMP, an excipient in SUBLOCADE at doses 1.8 times the MDD. Developmental delays and impaired cognitive function were reported in pups born to pregnant rats treated with NMP via inhalation during gestation at doses equivalent to the MDD of NMP via SUBLOCADE based on a body surface area comparison.
In an embryofetal development study in rats, SUBLOCADE administered subcutaneously to pregnant animals before mating and again on GD 7 during the period of organogenesis resulted in increased post-implantation loss, which correlated with higher mean number of resorptions and decreased number of viable fetuses per litter, and decreased mean fetal body weights at 900 mg/kg (approximately 38 times the maximum recommended human dose [MRHD] of 300 mg of SUBLOCADE on an AUC basis); however, similar effects were observed with an equivalent level of ATRIGEL® delivery system alone, indicating they may be attributable to the vehicle. Dose-related increases in incidences of skeletal malformations of the head and visceral malformations were observed with SUBLOCADE with significant changes at 900 mg/kg (approximately 38 times the MRHD on an AUC basis). Although similar effects were observed with equivalent levels of ATRIGEL® delivery system, the incidence of skeletal malformations, primarily skull malformations, was higher in the SUBLOCADE groups suggesting that buprenorphine contributed to the increased incidence. Based on these results, the NOAEL for developmental toxicity was 300 mg/kg (approximately 15 times the MRHD on an AUC basis).
In an embryofetal development study in rabbits, administration of a single subcutaneous injection of SUBLOCADE to pregnant animals on Gestation Day 7 during the period of organogenesis resulted an increased litter incidence of skeletal malformations at 155 mg/kg (approximately 7 times the MRHD on an AUC basis), which appear to be buprenorphine-related adverse effects. There was also an increased litter incidence of external malformations, visceral, and skeletal malformations and variations at 390 mg/kg SUBLOCADE (approximately 15 times the MRHD on an AUC basis); however, similar effects were observed with an equivalent level of the ATRIGEL® delivery system, indicating they may be attributable to the vehicle. In addition, increased post-implantation loss, which correlated with increased mean number of resorptions and decreased mean number of viable fetuses, and decreased fetal body weights were observed at 390 mg/kg (approximately 15 times the MRHD on an AUC basis); however, similar findings were also observed with an equivalent level of the ATRIGEL® delivery system alone. Based on these results, the NOAEL for developmental toxicity for SUBLOCADE was 78 mg/kg (approximately 3 times the MRHD on an AUC basis).
In a pre- and postnatal development study in rats, SUBLOCADE was administered subcutaneously to pregnant animals once during implantation (on Gestation Day 7) and once during weaning (on Lactation Day 7). There were no adverse effects on offspring survival, sexual maturation, behavioral assessment, or reproductive performance at up to 300 mg/kg (approximately 10 times the MRHD on an mg/m2 basis).
Risk Summary
Based on two studies in 13 lactating women maintained on buprenorphine treatment, buprenorphine and its metabolite norbuprenorphine are present in low levels in human milk and infant urine. Available data have not shown adverse reactions in breastfed infants. Caution should be exercised when SUBLOCADE is administered to a nursing woman. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for SUBLOCADE and any potential adverse effects on the breastfed child from the drug or from the underlying maternal condition.
Clinical Considerations
Advise breastfeeding women taking buprenorphine products to monitor the infant for increased drowsiness and breathing difficulties.
Data
Data were consistent from two studies (N=13) of breastfeeding infants whose mothers were maintained on sublingual doses of buprenorphine ranging from 2.4 to 24 mg/day, showing that the infants were exposed to less than 1% of the maternal daily dose.
In a study of six lactating women who were taking a median sublingual buprenorphine dose of 0.29 mg/kg/day 5 to 8 days after delivery, breast milk provided a median infant dose of 0.42 mcg/kg/day of buprenorphine and 0.33 mcg/kg/day of norbuprenorphine, equal to 0.2% and 0.12%, respectively, of the maternal weight-adjusted dose (relative dose/kg (%) of norbuprenorphine was calculated from the assumption that buprenorphine and norbuprenorphine are equipotent).
Data from a study of seven lactating women who were taking a median sublingual buprenorphine dose of 7 mg/day an average of 1.12 months after delivery indicated that the mean milk concentrations (Cavg) of buprenorphine and norbuprenorphine were 3.65 mcg/L and 1.94 mcg/L respectively. Based on the study data, and assuming milk consumption of 150 mL/kg/day, an exclusively breastfed infant would receive an estimated mean absolute infant dose (AID) of 0.55 mcg/kg/day of buprenorphine and 0.29 mcg/kg/day of norbuprenorphine, or a mean relative infant dose (RID) of 0.38% and 0.18%, respectively, of the maternal weight-adjusted dose.
Human Data
Chronic use of opioids may cause reduced fertility in females and males of reproductive potential. It is not known whether these effects on fertility are reversible [see Adverse Reactions (6.2)].
Animal Data
Infertility
Male
Male fertility may be reduced based on animal data demonstrating adverse effects of SUBLOCADE on sperm parameters [see Nonclinical Toxicology (13.1)].
Clinical Presentation
The manifestations of acute overdose include pinpoint pupils, sedation, hypotension, respiratory depression, and death.
Treatment of Overdose
In the event of overdose, the respiratory and cardiac status of the patient should be monitored carefully. When respiratory or cardiac functions are depressed, primary attention should be given to the re-establishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. Oxygen, IV fluids, vasopressors, and other supportive measures should be considered as indicated. Naloxone may be of value for the management of buprenorphine overdose. Higher than normal doses and repeated administration may be necessary.
Clinicians should consider the potential role and contribution of buprenorphine, other opioids, and other CNS depressant drugs in a patient's clinical presentation. Clinical data are limited with regards to the possible surgical removal of the depot. Two cases of surgical removal were reported in premarketing clinical studies.
Mu-Opioid Receptor Occupancy and Association With Opioid Blockade
In a Positron Emission Tomography (PET) study with SUBLOCADE in 2 subjects (one subject receiving 200 mg SC injections and one subject receiving 300 mg SC injections) with opioid use disorder, 75 to 92% occupancy of the mu-opioid receptors in the brain was maintained for 28 days following the last dose under steady-state conditions.
The opioid blockade study evaluated the blockade of subjective opioid effects, pharmacokinetics (PK) and safety of SC injections of SUBLOCADE. Stabilization doses of SL buprenorphine prior to injection of SUBLOCADE failed to provide full blockade of subjective effects of hydromorphone 18 mg IM. After SUBLOCADE injections at Weeks 0 and 4, on average, subjective effects of both 6 mg and 18 mg doses of hydromorphone were blocked; however, wide variability was seen across subjects. Complete blockade continued throughout the 8 weeks of observation that followed the 2nd SUBLOCADE injection [see Clinical Studies (14.1)].
Figure 10 illustrates the relationship between buprenorphine plasma level and drug liking after 18 mg hydromorphone IM.
Figure 10. Drug Liking VAS vs. Plasma Buprenorphine Concentration Following 18 mg Hydromorphone Challenges
Exposure-response relationships were assessed for illicit opioid use, based on urine samples negative for illicit opioids combined with self-reports negative for illicit opioid use, and withdrawal symptoms using data obtained from 489 opioid dependent patients in the double-blind Phase 3 Study (13-0001).
The observed plateau for maximal response was reached at buprenorphine plasma concentrations of approximately 2-3 ng/mL for illicit opioid use and 4 ng/mL for opioid withdrawal symptoms.
Population PK/PD modeling indicated that patients using opioids by the injectable route at baseline may require higher buprenorphine exposure compared to patients not using opioids by the injectable route at baseline.
Cardiac Electrophysiology
Serial ECGs were collected following a single dose and at steady-state to evaluate the effect of SUBLOCADE on the QT interval in five clinical studies including the Phase 3 study. In a Phase 3 study, seven patients had an increase from baseline QTc greater than 60 msec at any time [2/203 patients (1.0%) in the 300 mg/100 mg group and 5/201 patients (2.0%) in the 300 mg/300 mg group] and one patient in the 300 mg/300 mg group was found to have a QTc greater than 500 msec. These QTc findings were all sporadic and transient and none led to aberrant ventricular rhythm. Review of ECG and adverse event data provided no evidence for syncope, seizure, or ventricular tachycardia or fibrillation.
Physiological Effects
Buprenorphine in IV (2, 4, 8, 12 and 16 mg) and sublingual (12 mg) doses have been administered to opioid-experienced subjects who were not physically dependent to examine cardiovascular, respiratory, and subjective effects at doses comparable to those used for treatment of opioid dependence. Compared to placebo, there were no statistically significant differences among any of the treatment conditions for blood pressure, heart rate, respiratory rate, O2 saturation, or skin temperature across time. Systolic BP was higher in the 8 mg group than placebo (3 hour AUC values). Minimum and maximum effects were similar across all treatments. Subjects remained responsive to low voice and responded to computer prompts. Some subjects showed irritability, but no other changes were observed. The respiratory effects of sublingual buprenorphine were compared with the effects of methadone in a double-blind, parallel group, dose ranging comparison of single doses of buprenorphine sublingual solution (1, 2, 4, 8, 16, or 32 mg) and oral methadone (15, 30, 45, or 60 mg) in non-dependent, opioid-experienced volunteers. In this study, hypoventilation not requiring medical intervention was reported more frequently after buprenorphine doses of 4 mg and higher than after methadone. Both drugs decreased O2 saturation to the same degree.
In clinical studies conducted with SUBLOCADE at doses ranging from 50 to 300 mg, no incidences of temperature elevations, or clinically significant lowering of oxygen saturation were observed.
Androgen Deficiency
Chronic use of opioids may influence the hypothalamic-pituitary-gonadal axis, leading to androgen deficiency that may manifest as low libido, impotence, erectile dysfunction, amenorrhea, or infertility. The causal role of opioids in the clinical syndrome of hypogonadism is unknown because the various medical, physical, lifestyle, and psychological stressors that may influence gonadal hormone levels have not been adequately controlled for in studies conducted to date. Patients presenting with symptoms of androgen deficiency should undergo laboratory evaluation.
Pharmacodynamic Interaction with Fentanyl
An open-label, cross-over study was conducted in 8 opioid-tolerant subjects to assess the ability of intravenous buprenorphine to prevent respiratory depression associated with high doses of fentanyl administered in a clinical setting. Opioid-tolerant subjects were medically stable and taking oral morphine equivalents of ≥ 90 mg daily with no other CNS depressant use. Buprenorphine infusions at three dose levels and placebo infusions were administered, followed by up to four doses of fentanyl. The three intravenous buprenorphine dose levels were designated as low (0.25 mg/70kg bolus + 0.1 mg/70kg/hr), mid (0.5 mg/70kg bolus + 0.2 mg/70kg/hr), and high (1.25 mg/70kg bolus + 0.5 mg/70kg/hr). The low, mid, and high buprenorphine dose levels produced average plasma concentrations (from 2 hours to 6 hours after infusion onset) of 1.06 ng/mL, 2.26 ng/mL, and 6.04 ng/mL, respectively.
Escalating intravenous fentanyl boluses of 0.25, 0.35, 0.50 and 0.70 mg/70 kg (up to a maximum cumulative dose of 1.8 mg/70 kg) were administered over 90 seconds at +2hr, +3hr, +4hr and +5hr after the start of intravenous infusion of buprenorphine or placebo. Apnea events after each fentanyl bolus are shown in Figure 11. Four of the 8 subjects in the placebo infusion groups discontinued prior to the fourth fentanyl bolus because of apnea (2 after the second bolus and 2 after the third bolus); 3 of the remaining 4 subjects experienced apnea after the fourth fentanyl dose. All 8 subjects in the buprenorphine infusion groups completed the fentanyl boluses and 2 of the 8 experienced apnea.
Figure 11 Occurrence of Apnea Events After Fentanyl Doses in a Pharmacodynamic Interaction Study
There were 2 opioid-tolerant subjects in the low intravenous buprenorphine (BUP) group (Arm A), 3 in the mid BUP group (Arm B), and 3 in the high BUP group (Arm C). The numbers in parentheses represent the geometric mean of buprenorphine plasma concentrations in each group from 2 hours to 6 hours after infusion onset. The escalating fentanyl doses 1 to 4 were 0.25, 0.35, 0.50 and 0.70 mg/70 kg body weight. The same subject in the low BUP group had apnea after the third and fourth fentanyl boluses.
Absorption
The pharmacokinetics (PK) of buprenorphine following subcutaneous injection of SUBLOCADE was evaluated in subjects with opioid use disorder after single doses (50 mg to 200 mg) and repeated doses (50 to 300 mg) separated by 28 days for up to 12 injections.
After SUBLOCADE injection, an initial buprenorphine peak was observed and the median Tmax occurred at 24 hours after injection. After the initial buprenorphine peak, the plasma buprenorphine concentrations decreased slowly to a plateau. Steady-state was achieved at 4-6 months.
Mean buprenorphine plasma concentrations levels for Cavg, Cmax and Ctrough at steady-state are presented in Table 7 for SUBLOCADE in comparison to daily transmucosal buprenorphine.
Table 7 Comparison of Steady-state Buprenorphine Plasma Exposure Between Daily Transmucosal Buprenorphine and Once Monthly SUBLOCADE at Trough (Ctrough), Average (Cavg) and Peak (Cmax) Levels (Geometric Mean (CV%))
| Pharmacokinetic parameters | Transmucosal Buprenorphine | SUBLOCADE |
| 8 mg | 12 mg | 16 mg | 24 mg | 100 mg | 300 mg |
| Cavg,ss (ng/mL)
| 1.37 (40)
| 1.79 (40)
| 2.16 (40)
| 2.84 (40)
| 2.87 (32)
| 6.32 (32)
|
| Cmax,ss (ng/mL)
| 4.27 (45)
| 5.60 (45)
| 6.77 (45)
| 8.86 (45)
| 5.10 (33)
| 11.81 (35)
|
| Ctrough,ss (ng/mL)
| 0.66 (63)
| 0.87 (63)
| 1.04 (61)
| 1.37 (62)
| 2.46 (40)
| 5.47 (39)
|
Distribution
Buprenorphine is approximately 96% protein bound, primarily to alpha and beta globulin.
Elimination
Buprenorphine is metabolized and eliminated in urine and feces. The apparent terminal plasma half-life of buprenorphine following subcutaneous injection of SUBLOCADE ranged between 43 to 60 days as a result of the slow release of buprenorphine from the subcutaneous depot.
A study assessing buprenorphine exposure 22 to 38 months following the last SUBLOCADE injection indicated that buprenorphine could potentially be detected in plasma and urine over that time period. Concentrations in urine were more variable than in plasma and generally higher depending on the test used. Hence, it is expected that buprenorphine will be detected in patients for a longer time in urine than in plasma.
Metabolism
Buprenorphine is metabolized to its major metabolite, norbuprenorphine, primarily by CYP3A4. Norbuprenorphine can further undergo glucuronidation. Norbuprenorphine has been found to bind opioid receptors in vitro; however, it has not been studied clinically for opioid-like activity. Norbuprenorphine steady-state plasma concentrations in humans after subcutaneous injection of SUBLOCADE are low compared to buprenorphine (AUC norbuprenorphine/buprenorphine ratio of 0.20 to 0.40).
Excretion
A mass balance study of buprenorphine administered by IV infusion in humans showed complete recovery of radiolabel in urine (30%) and feces (69%) collected up to 11 days after dosing. Almost all of the dose was accounted for in terms of buprenorphine, norbuprenorphine, and two unidentified buprenorphine metabolites. In urine, most of buprenorphine and norbuprenorphine were conjugated (buprenorphine: 1% free and 9.4% conjugated; norbuprenorphine: 2.7% free and 11% conjugated). In feces, almost all of the buprenorphine and norbuprenorphine were free (buprenorphine: 33% free and 5% conjugated; norbuprenorphine: 21% free and 2% conjugated).
Drug Interaction Studies
CYP3A4 Inhibitors and Inducers
The effects of co-administered CYP3A4 inhibitors and inducers on buprenorphine exposure in subjects treated with SUBLOCADE have not been studied; however, such interactions have been established in studies using transmucosal buprenorphine. The effects of buprenorphine may be dependent on the route of administration.
Buprenorphine is metabolized to norbuprenorphine primarily by cytochrome CYP3A4; therefore, potential interactions may occur when SUBLOCADE is given concurrently with agents that affect CYP3A4 activity. The effects of co-administered CYP3A4 inducers or inhibitors have been established in studies using transmucosal buprenorphine. Patients who transfer to SUBLOCADE treatment from a regimen of transmucosal buprenorphine used concomitantly with CYP3A4 inhibitors (e.g., ketoconazole), macrolide antibiotics (e.g., erythromycin), or HIV protease inhibitors, or CYP3A4 inducer (e.g., phenobarbital, carbamazepine, phenytoin, rifampicin) should be monitored to ensure that the plasma buprenorphine level provided by SUBLOCADE is adequate and not excessive [see Drug Interactions (7)].
Buprenorphine has been found to be a CYP2D6 and CYP3A4 inhibitor and its major metabolite, norbuprenorphine, has been found to be a moderate CYP2D6 inhibitor in in vitro studies employing human liver microsomes. However, the plasma concentrations of buprenorphine and norbuprenorphine resulting from therapeutic SUBLOCADE doses are not expected to significantly affect metabolism of other co-medications.
Specific Populations
Based on population pharmacokinetic analyses, age, sex and race do not have a clinically meaningful effect on PK of SUBLOCADE.
Hepatic Impairment
The effect of hepatic impairment on the pharmacokinetics of SUBLOCADE has not been studied. However, the effect of hepatic impairment on the PK of buprenorphine has been evaluated in a study using 2 mg/0.5 mg buprenorphine/naloxone sublingual tablet in subjects with various degrees of hepatic impairment as indicated by Child-Pugh criteria. While no clinically relevant changes were observed in subjects with mild hepatic impairment, buprenorphine plasma exposure was increased by 64% and 181% in subjects with moderate and severe hepatic impairment, respectively, compared to healthy subjects [see Use in Specific Populations (8.6)].
Renal Impairment
The effect of renal impairment on the pharmacokinetics of SUBLOCADE has not been studied. Clinical studies of SUBLOCADE did not include subjects with severe renal impairment.
Less than 1% is excreted as unchanged buprenorphine in urine following IV buprenorphine administration. No differences in buprenorphine pharmacokinetics were observed between 9 dialysis-dependent and 6 normal patients following IV administration of 0.3 mg buprenorphine [see Use in Specific Populations (8.7)].
Population PK analyses indicated no notable relationship between creatinine clearance and steady-state buprenorphine plasma concentrations.
HCV infection
In subjects with HCV infection but no sign of hepatic impairment, the changes in the mean Cmax, AUC0-last, and half-life values of buprenorphine were not clinically significant in comparison to healthy subjects without HCV infection. No dose adjustment is needed in patients with HCV infection.
Carcinogenicity
Long-term studies in animals performed to evaluate carcinogenic potential of SUBLOCADE have not been conducted. However, the carcinogenic potential of the active drug substance in SUBLOCADE, buprenorphine, has been evaluated in Sprague-Dawley rats and CD-1 mice.
In the carcinogenicity study conducted in Sprague-Dawley rats, buprenorphine was administered in the diet at doses of 0.6, 5.5, and 56 mg/kg/day (approximately 0.5, 5, and 50 times the recommended human monthly SC dose of 300 mg of buprenorphine) for 27 months. A statistically significant dose-related increase in Leydig cell tumors occurred. In an 86 week study in CD-1 mice, buprenorphine was not carcinogenic at dietary doses up to 100 mg/kg/day (approximately 45 times the recommended human monthly SC dose of 300 mg of buprenorphine).
NMP, an excipient in SUBLOCADE, produced an increase in hepatocellular adenomas and carcinomas in male and female mice at 6 and 8 times the maximum daily dose (MDD) of NMP via SUBLOCADE. The clinical significance of these findings is unclear. No tumors were noted at 1 and 1.3 times the MDD. In 2-year inhalation and dietary studies in rats, NMP did not result in evidence of carcinogenicity.
Mutagenicity
No evidence of mutagenic potential for subcutaneous SUBLOCADE was found in in vivo subcutaneous micronucleus test using rats' marrow.
Mutagenic potential for buprenorphine was studied in a series of tests utilizing gene, chromosome, and DNA interactions in both prokaryotic and eukaryotic systems. Results were negative in yeast (S. cerevisiae) for recombinant, gene convertant, or forward mutations; negative in Bacillus subtilis “rec” assay, negative for clastogenicity in CHO cells, Chinese hamster bone marrow and spermatogonia cells, and negative in the mouse lymphoma L5178Y assay.
Results were equivocal in the Ames test: negative in studies in two laboratories, but positive for frame shift mutation at a high dose (5 mg/plate) in a third study. Results were positive in the Green-Tweets (E. coli) survival test, positive in a DNA synthesis inhibition (DSI) test with testicular tissue from mice, for both in vivo and in vitro incorporation of [3H]thymidine, and positive in unscheduled DNA synthesis (UDS) test using testicular cells from mice.
Impairment of Fertility
In a fertility study in rats, female mating, fertility, and fecundity indices were unaffected by the SC administration of SUBLOCADE up to 900 mg/kg buprenorphine (approximately 38 times the maximum recommended human dose [MRHD] of 300 mg on an AUC basis). However, higher mean post-implantation loss was observed with SUBLOCADE at 900 mg/kg buprenorphine and at an equivalent level of ATRIGEL® alone, which correlated with higher mean number of resorptions and reduced mean number of viable fetuses/litter size. Mean gravid uterine weight and mean final body weight were lower with SUBLOCADE at 900 mg/kg buprenorphine and an equivalent level of ATRIGEL® alone, and correlated with higher mean number of resorptions and lower fetal body weights. The NOAEL for female fertility was 900 mg/kg and the NOAEL for female-mediated developmental parameters was 600 mg/kg (approximately 25 times the MRHD on an AUC basis).
Male fertility and reproduction indices were lower as evidenced by abnormal sperm parameters (low motility, low mean number of sperm, and higher percentage of abnormal sperm) with SUBLOCADE at 600 mg/kg and with an equivalent level of ATRIGEL®. The NOAEL for male fertility parameters, including sperm analysis, and male-mediated developmental parameters was 300 mg/kg (approximately 32 times the MRHD on an AUC basis).
Adverse effects on testes and male fertility were noted in published study in which rats were treated for 10 weeks with daily oral doses of NMP, an excipient in SUBLOCADE at greater than 11.6 times the MDD and resulted in male-mediated adverse effects on offspring (decreased pup weight and survival) at daily doses 3.5 times the MDD of NMP delivered by SUBLOCADE. No adverse effects were noted at oral doses equivalent to the dose of NMP delivered by SUBLOCADE.
SUBLOCADE Risk Evaluation and Mitigation Strategy (REMS)
Advise patients that because of the risk of serious harm or death due to intravenous self-administration, SUBLOCADE is available only through a restricted program called the SUBLOCADE REMS Program. Healthcare settings and pharmacies are certified and only dispense SUBLOCADE directly to a healthcare provider for administration by healthcare providers [see Warnings and Precautions (5.2)].
Life Threatening Respiratory Depression
Educate patients and caregivers on how to recognize respiratory depression and emphasize the importance of calling 911 or getting emergency medical help right away in the event of a known or suspected overdose [see Warnings and Precautions 5.4)].
Patient Access to Naloxone for the Emergency Treatment of Opioid Overdose
Because patients being treated for opioid use disorder are at risk for relapse, discuss the importance of having access to naloxone with the patient and caregiver. Also discuss the importance of having access to naloxone if there are household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose.
Inform patients and caregivers of the options for obtaining naloxone as permitted by individual state naloxone dispensing and prescribing requirements or guidelines (e.g., by prescription, directly from a pharmacist, or as part of a community-based program).
Educate patients and caregivers on how to recognize the signs and symptoms of an opioid overdose.
Explain to patients and caregivers that naloxone's effects are temporary, and that they must call 911 or get emergency medical help right away in all cases of known or suspected opioid overdose, even if naloxone is administered. Repeat administration may be necessary, particularly for overdose involving buprenorphine, because naloxone is often not effective at the doses available for patient access [see Dosage and Administration (2.3), Warnings and Precautions (5.4), Overdosage (10)].
If naloxone is prescribed, also advise patients and caregivers:
- How to treat with naloxone in the event of an opioid overdose
- To tell family and friends about their naloxone and to keep it in a place where family and friends can easily access it in an emergency
- To read the Patient Information (or other educational material) that will come with their naloxone. Emphasize the importance of doing this before an opioid emergency happens, so the patient and caregiver will know what to do
Interaction With Benzodiazepines and Other CNS Depressants
Inform patients and caregivers that potentially fatal additive effects may occur if SUBLOCADE is used with benzodiazepines or other CNS depressants, including alcohol. Counsel patients that such medications should not be used concomitantly unless supervised by a healthcare provider [see Warnings and Precautions (5.4, 5.5), Drug Interactions (7)].
Serotonin Syndrome
Inform patients that SUBLOCADE could cause a rare but potentially life-threatening condition resulting from concomitant administration of serotonergic drugs. Warn patients of the symptoms of serotonin syndrome and to seek medical attention right away if symptoms develop. Instruct patients to inform their healthcare providers if they are taking, or plan to take serotonergic medications [see Drug Interactions (7)].
Adrenal Insufficiency
Inform patients that SUBLOCADE could cause adrenal insufficiency, a potentially life-threatening condition. Adrenal insufficiency may present with non-specific symptoms and signs such as nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure. Advise patients to seek medical attention if they experience a constellation of these symptoms [see Warnings and Precautions (5.8)].
Anaphylaxis
Inform patients that anaphylaxis has been reported with buprenorphine. Advise patients how to recognize such a reaction and when to seek medical attention [see Warnings and Precautions (5.11)].
Driving or Operating Heavy Machinery
Caution patients that SUBLOCADE may impair the mental or physical abilities required for the performance of potentially dangerous tasks such as driving or operating hazardous machinery. Instruct patients not to drive or operate hazardous machinery until they are reasonably certain that SUBLOCADE does not adversely affect their ability to engage in such activities [see Warnings and Precautions (5.17)].
Dependence and Withdrawal
Inform patients that SUBLOCADE can cause drug dependence and that withdrawal signs and symptoms may occur when the medication is discontinued [see Warnings and Precautions (5.9, 5.12)].
Orthostatic Hypotension
Inform patients that, like other opioids, SUBLOCADE may produce orthostatic hypotension in ambulatory individuals [see Warnings and Precautions (5.18)].
Long Duration of Action
Inform patients that they may have detectable levels of buprenorphine for a prolonged period of time after treatment with SUBLOCADE. Considerations of drug-drug interactions, buprenorphine effects, and analgesia may continue to be relevant for several months after the last injection [see Clinical Pharmacology (12.3)].
Drug Interactions
Instruct patients to inform their healthcare providers of any other prescription medications, over the-counter medications, or herbal preparations that are prescribed or currently being used [see Drug Interactions (7)].
Pregnancy
Neonatal Opioid Withdrawal Syndrome
Advise women that if they are pregnant while being treated with SUBLOCADE, the baby may have signs of withdrawal at birth and that withdrawal is treatable [see Warnings and Precautions (5.6), Use in Specific Populations (8.1)].
Embryofetal Toxicity
Advise women of childbearing potential who become pregnant or are planning to become pregnant to consult their healthcare provider regarding the possible effects of using SUBLOCADE during pregnancy [see Use in Specific Populations (8.1)].
Lactation
Warn patients that buprenorphine passes into breast milk. Advise the nursing mother taking buprenorphine to monitor the infant for increased drowsiness and breathing difficulties [see Use in Specific Populations (8.2)].
Infertility
Inform patients that chronic use of opioids may cause reduced fertility. It is not known whether these effects on fertility are reversible [see Use in Specific Populations (8.3), Clinical Pharmacology (12.2)].
Emergency Analgesia
Patients should be advised to instruct their family members to, in the event of emergency, inform the treating healthcare provider or emergency room staff that the patient is physically dependent on an opioid and that the patient is being treated with SUBLOCADE [see Warnings and Precautions (5.13)].
Clinical Monitoring
Tell your patients to seek emergency attention if they have signs or symptoms of respiratory or CNS depression or overdose [see Warnings and Precautions (5.4, 5.5)].
Tell your patients not to tamper with or try to remove their depot [see Dosage and Administration (2.8)].
SUBLOCADE® and SUBOXONE® are registered trademarks of Indivior UK Limited.
Manufactured for Indivior Inc.
North Chesterfield, VA 23235
By AMRI
Burlington, MA 01803