Inhibitors of CYP3A4 and CYP2D6
The concomitant use of Hydrocodone Bitartrate and Acetaminophen Tablets and CYP3A4 inhibitors, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), and protease inhibitors (e.g., ritonavir), can increase the plasma concentration of the hydrocodone from Hydrocodone Bitartrate and Acetaminophen Tablets, resulting in increased or prolonged opioid effects. These effects could be more pronounced with concomitant use of Hydrocodone Bitartrate and Acetaminophen Tablets and both CYP3A4 and CYP2D6 inhibitors, particularly when an inhibitor is added after a stable dose of Hydrocodone Bitartrate and Acetaminophen Tablets is achieved [see Warnings].
After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the hydrocodone plasma concentration will decrease [see Clinical Pharmacology], resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to Hydrocodone Bitartrate and Acetaminophen Tablets.
If concomitant use is necessary, consider dosage reduction of Hydrocodone Bitartrate and Acetaminophen Tablets until stable drug effects are achieved. Evaluate patients at frequent intervals for respiratory depression and sedation. If a CYP3A4 inhibitor is discontinued, consider increasing the Hydrocodone Bitartrate and Acetaminophen Tablets dosage until stable drug effects are achieved. Evaluate for signs or symptoms of opioid withdrawal.
Inducers of CYP3A4
The concomitant use of Hydrocodone Bitartrate and Acetaminophen Tablets and CYP3A4 inducers, such as rifampin, carbamazepine, and phenytoin, can decrease the plasma concentration of hydrocodone [see Clinical Pharmacology], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to hydrocodone [see Warnings].
After stopping a CYP3A4 inducer, as the effects of the inducer decline, the hydrocodone plasma concentration will increase [see Clinical Pharmacology], which could increase or prolong both the therapeutic effects and adverse reactions, and may cause serious respiratory depression.
If concomitant use is necessary, consider increasing the Hydrocodone Bitartrate and Acetaminophen Tablets dosage until stable drug effects are achieved. Evaluate the patient for signs and symptoms of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider Hydrocodone Bitartrate and Acetaminophen Tablets dosage reduction and evaluate patients at frequent intervals for signs of respiratory depression and sedation.
Benzodiazepines and Other Central Nervous System (CNS) Depressants
Due to additive pharmacologic effect, the concomitant use of benzodiazepines and other CNS depressants, such as benzodiazepines and other sedative hypnotics, anxiolytics, and tranquilizers, muscle relaxants, general anesthetics, antipsychotics, and other opioids, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death.
Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Inform patients and caregivers of this potential interaction, educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider prescribing naloxone for the emergency treatment of opioid overdose [see Warnings].
Serotonergic Drugs
The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system, such as selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), and monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue), has resulted in serotonin syndrome [see Precautions; Information for Patients].
If concomitant use is warranted, frequently evaluate the patient, particularly during treatment initiation and dose adjustment. Discontinue Hydrocodone Bitartrate and Acetaminophen Tablets if serotonin syndrome is suspected.
Monoamine Oxidase Inhibitors (MAOIs)
The concomitant use of opioids and MAOIs, such as phenelzine, tranylcypromine, or linezolid, may manifest as serotonin syndrome, or opioid toxicity (e.g., respiratory depression, coma) [see Warnings].
The use of Hydrocodone Bitartrate and Acetaminophen Tablets is not recommended for patients taking MAOIs or within 14 days of stopping such treatment.
If urgent use of an opioid is necessary, use test doses and frequent titration of small doses to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Mixed Agonist/Antagonist and Partial Agonist Opioid Analgesics
The concomitant use of opioids with other opioid analgesics, such as butorphanol, nalbuphine, pentazocine, may reduce the analgesic effect of Hydrocodone Bitartrate and Acetaminophen Tablets and/or precipitate withdrawal symptoms.
Advise patient to avoid concomitant use of these drugs.
Muscle Relaxants
Hydrocodone Bitartrate and Acetaminophen Tablets may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression.
If concomitant use is warranted, because respiratory depression that may be greater than otherwise expected and decrease the dosage of Hydrocodone Bitartrate and Acetaminophen Tablets and/or the muscle relaxant as necessary. Due to the risk of respiratory depression with concomitant use of muscle relaxants and opioids, consider prescribing naloxone for the emergency treatment of opioid overdose [see Warnings].
Diuretics
Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone.
If concomitant use is warranted, evaluate patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed.
Anticholinergic Drugs
The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
If concomitant use is warranted, evaluate patients for signs of urinary retention or reduced gastric motility when Hydrocodone Bitartrate and Acetaminophen Tablets are used concomitantly with anticholinergic drugs.
Drug/Laboratory Test Interactions
Acetaminophen may produce false-positive test results for urinary 5-hydroxyindoleacetic acid.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis
Long-term studies to evaluate the carcinogenic potential of the combination of Hydrocodone Bitartrate and Acetaminophen Tablets have not been conducted.
Long-term studies in mice and rats have been completed by the National Toxicology Program to evaluate the carcinogenic potential of acetaminophen. In 2-year feeding studies, F344/N rats and B6C3F1 mice were fed a diet containing acetaminophen up to 6000 ppm. Female rats demonstrated equivocal evidence of carcinogenic activity based on increased incidences of mononuclear cell leukemia at 0.8 times the maximum human daily dose (MHDD) of 4 grams/day, based on a body surface area comparison. In contrast, there was no evidence of carcinogenic activity in male rats that received up to 0.7 times or mice at up to 1.2-1.4 times the MHDD, based on a body surface area comparison.
Mutagenesis
In the published literature, acetaminophen has been reported to be clastogenic when administered at 1500 mg/kg/day to the rat model (3.6-times the MHDD, based on a body surface area comparison). In contrast, no clastogenicity was noted at a dose of 750 mg/kg/day (1.8-times the MHDD, based on a body surface area comparison), suggesting a threshold effect.
Impairment of Fertility
In studies conducted by the National Toxicology Program, fertility assessments with acetaminophen have been completed in Swiss CD-1 mice via a continuous breeding study. There were no effects on fertility parameters in mice consuming up to 1.7 times the MHDD of acetaminophen, based on a body surface area comparison.
Although there was no effect on sperm motility or sperm density in the epididymis, there was a significant increase in the percentage of abnormal sperm in mice consuming 1.78 times the MHDD (based on a body surface comparison) and there was a reduction in the number of mating pairs producing a fifth litter at this dose, suggesting the potential for cumulative toxicity with chronic administration of acetaminophen near the upper limit of daily dosing.
Published studies in rodents report that oral acetaminophen treatment of male animals at doses that are 1.2 times the MHDD and greater (based on a body surface comparison) result in decreased testicular weights, reduced spermatogenesis, reduced fertility, and reduced implantation sites in females given the same doses. These effects appear to increase with the duration of treatment. The clinical significance of these findings is not known.
Infertility
Use of opioids for an extended period of time 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].
Pregnancy Teratogenic Effects
There are no adequate and well-controlled studies in pregnant women. Hydrocodone Bitartrate and Acetaminophen Tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Nonteratogenic Effects
Fetal/Neonatal Adverse Reactions
Use of opioid analgesics for an extended period of time pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth.
Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity, abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings].
Labor or Delivery
Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates. An opioid antagonist, such as naloxone, must be available for reversal of opioid-induced respiratory depression in the neonate. Hydrocodone Bitartrate and Acetaminophen Tablets are not recommended for use in pregnant women during or immediately prior to labor, when other analgesic techniques are more appropriate. Opioid analgesics, including Hydrocodone Bitartrate and Acetaminophen Tablets, can prolong labor through actions which temporarily reduce the strength, duration, and frequency of uterine contractions. However, this effect is not consistent and may be offset by an increased rate of cervical dilation, which tends to shorten labor. Monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression.
Nursing Mothers
Hydrocodone is present in human milk.
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Hydrocodone Bitartrate and Acetaminophen Tablets and any potential adverse effects on the breastfed infant from Hydrocodone Bitartrate and Acetaminophen Tablets or from the underlying maternal condition.
Infants exposed to Hydrocodone Bitartrate and Acetaminophen Tablets through breast milk should be monitored for excess sedation and respiratory depression. Withdrawal symptoms can occur in breastfed infants when maternal administration of an opioid analgesic is stopped, or when breast-feeding is stopped.
Pediatric Use
Safety and effectiveness of Hydrocodone Bitartrate and Acetaminophen Tablets in pediatric patients have not been established.
Geriatric Use
Elderly patients (aged 65 years or older) may have increased sensitivity to Hydrocodone Bitartrate and Acetaminophen Tablets. In general, use caution when selecting a dosage for an elderly patient, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy.
Respiratory depression is the chief risk for elderly patients treated with opioids, and has occurred after large initial doses were administered to patients who were not opioid-tolerant or when opioids were co-administered with other agents that depress respiration. Titrate the dosage of Hydrocodone Bitartrate and Acetaminophen Tablets slowly in geriatric patients and frequently reevaluate the patient for signs of central nervous system and respiratory depression [see Warnings].
Hydrocodone and acetaminophen are known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to regularly evaluate renal function.
Hepatic Impairment
Patients with hepatic impairment may have higher plasma hydrocodone concentrations than those with normal function. Use a low initial dose of Hydrocodone Bitartrate and Acetaminophen Tablets in patients with hepatic impairment and follow closely for adverse events such as respiratory depression and sedation.
Renal Impairment
Patients with renal impairment may have higher plasma hydrocodone concentrations than those with normal function. Use a low initial dose Hydrocodone Bitartrate and Acetaminophen Tablets in patients with renal impairment and follow closely for adverse events such as respiratory depression and sedation.