Use with Other CNS Depressants
If alprazolam extended-release tablets are to be combined with other psychotropic agents or anticonvulsant drugs, careful consideration should be given to the pharmacology of the agents to be employed, particularly with compounds which might potentiate the action of benzodiazepines. The benzodiazepines, including alprazolam, produce additive CNS depressant effects when coadministered with other psychotropic medications, anticonvulsants, antihistaminics, ethanol and other drugs which themselves produce CNS depression.
Use with Imipramine and Desipramine
The steady state plasma concentrations of imipramine and desipramine have been reported to be increased an average of 31% and 20%, respectively, by the concomitant administration of alprazolam tablets in doses up to 4 mg/day. The clinical significance of these changes is unknown.
Drugs that inhibit alprazolam metabolism via cytochrome P450 3A
The initial step in alprazolam metabolism is hydroxylation catalyzed by cytochrome P450 3A (CYP3A). Drugs which inhibit this metabolic pathway may have a profound effect on the clearance of alprazolam (see CONTRAINDICATIONS and WARNINGS for additional drugs of this type).
Drugs demonstrated to be CYP3A inhibitors of possible clinical significance on the basis of clinical studies involving alprazolam (caution is recommended during coadministration with alprazolam)
Fluoxetine--Coadministration of fluoxetine with alprazolam increased the maximum plasma concentration of alprazolam by 46%, decreased clearance by 21%, increased half-life by 17%, and decreased measured psychomotor performance.
Propoxyphene--Coadministration of propoxyphene decreased the maximum plasma concentration of alprazolam by 6%, decreased clearance by 38%, and increased half-life by 58%.
Oral Contraceptives--Coadministration of oral contraceptives increased the maximum plasma concentration of alprazolam by 18%, decreased clearance by 22%, and increased half-life by 29%.
Drugs and other substances demonstrated to be CYP3A inhibitors on the basis of clinical studies involving benzodiazepines metabolized similarly to alprazolam or on the basis of in vitro studies with alprazolam or other benzodiazepines (caution is recommended during coadministration with alprazolam)
Available data from clinical studies of benzodiazepines other than alprazolam suggest a possible drug interaction with alprazolam for the following: diltiazem, isoniazid, macrolide antibiotics such as erythromycin and clarithromycin, and grapefruit juice. Data from in vitro studies of alprazolam suggest a possible drug interaction with alprazolam for the following: sertraline and paroxetine. However, data from an in vivo drug interaction study involving a single dose of alprazolam 1 mg and steady state doses of sertraline (50 to 150 mg/day) did not reveal any clinically significant changes in the pharmacokinetics of alprazolam. Data from in vitro studies of benzodiazepines other than alprazolam suggest a possible drug interaction for the following: ergotamine, cyclosporine, amiodarone, nicardipine, and nifedipine. Caution is recommended during the coadministration of any of these with alprazolam (see WARNINGS).
Drugs demonstrated to be inducers of CYP3A
Carbamazepine can increase alprazolam metabolism and therefore can decrease plasma levels of alprazolam.
Other Adverse Events Observed During the Premarketing Evaluation of Alprazoalam Extended-Release Tablets
Following is a list of MedDRA terms that reflect treatment-emergent adverse events reported by 531 patients with panic disorder treated with alprazolam extended-release tablets. All potentially important reported events are included except those already listed in the above table or elsewhere in labeling, those events for which a drug cause was remote, those event terms that were so general as to be uninformative, and those events that occurred at rates similar to background rates in the general population. It is important to emphasize that, although the events reported occurred during treatment with alprazolam extended-release tablets, they were not necessarily caused by the drug. Events are further categorized by body system and listed in order of decreasing frequency according to the following definitions: frequent adverse events are those occurring on 1 or more occasions in at least 1/l00 patients; infrequent adverse events are those occurring in less than 1/100 patients but at least 1/1000 patients; rare events are those occurring in fewer than 1/1000 patients.
Cardiac disorders: Frequent: palpitation; Infrequent: sinus tachycardia
Ear and Labyrinth disorders: Frequent: Vertigo; Infrequent: tinnitus, ear pain
Eye disorders: Frequent: blurred vision; Infrequent: mydriasis, photophobia
Gastrointestinal disorders: Frequent: diarrhea, vomiting, dyspepsia, abdominal pain; Infrequent: dysphagia, salivary hypersecretion
General disorders and administration site conditions: Frequent: malaise, weakness, chest pains; Infrequent: fall, pyrexia, thirst, feeling hot and cold, edema, feeling jittery, sluggishness, asthenia, feeling drunk, chest tightness, increased energy, feeling of relaxation, hangover, loss of control of legs, rigors
Musculoskeletal and connective tissue disorders: Frequent: back pain, muscle cramps, muscle twitching
Nervous system disorders: Frequent: headache, dizziness, tremor; Infrequent: amnesia, clumsiness, syncope, hypotonia, seizures, depressed level of consciousness, sleep apnea syndrome, sleep talking, stupor
Psychiatric system disorders: Frequent: irritability, insomnia, nervousness, derealization, libido increased, restlessness, agitation, depersonalization, nightmare; Infrequent: abnormal dreams, apathy, aggression, anger, bradyphrenia, euphoric mood, logorrhea, mood swings, dysphonia, hallucination, homicidal ideation, mania, hypomania, impulse control, psychomotor retardation, suicidal ideation
Renal and urinary disorders: Frequent: difficulty in micturition; Infrequent: urinary frequency, urinary incontinence
Respiratory, thoracic, and mediastinal disorders: Frequent: nasal congestion, hyperventilation; Infrequent: choking sensation, epistaxis, rhinorrhea
Skin and subcutaneous tissue disorders: Frequent: sweating increased; Infrequent: clamminess, rash, urticaria
Vascular disorders: Infrequent: hypotension
The categories of adverse events reported in the clinical development program for alprazoalam tablets in the treatment of panic disorder differ somewhat from those reported for alprazolam extended-release tablets because the clinical trials with alprazolam tablets and alprazolam extended-release tablets used different standard medical nomenclature for reporting the adverse events. Nevertheless, the types of adverse events reported in the clinical trials with alprazolam tablets were generally the same as those reported in the clinical trials with alprazolam extended-release tablets.
Discontinuation-Emergent Adverse Events Occurring at an Incidence of 5% or More Among Patients Treated with Alprazolam Extended-Release Tablets
The following table shows the incidence of discontinuation-emergent adverse events that occurred during short-term, placebo-controlled trials in 5% or more of patients treated with alprazolam extended-release tablets where the incidence in patients treated with alprazolam extended-release tablets was two times greater than the incidence in placebo-treated patients.
Discontinuation-Emergent Symptoms: Incidence in Short-Term, Placebo-Controlled Trials with Alprazolam Extended-Release Tablets| System Organ Class/Adverse Event | Percentage of Patients Reporting Adverse Event |
Alprazolam Extended-Release Tablets (n=422) | Placebo (n=261) |
| Nervous system disorders | | |
| Tremor | 28.2 | 10.7 |
| Headache | 26.5 | 12.6 |
| Hypoesthesia | 7.8 | 2.3 |
| Paresthesia | 7.1 | 2.7 |
| Psychiatric disorders | | |
| Insomnia | 24.2 | 9.6 |
| Nervousness | 21.8 | 8.8 |
| Depression | 10.9 | 5.0 |
| Derealization | 8.0 | 3.8 |
| Anxiety | 7.8 | 2.7 |
| Depersonalization | 5.7 | 1.9 |
| Gastrointestinal disorders | | |
| Diarrhea | 12.1 | 3.1 |
Respiratory, thoracic and mediastinal disorders | | |
| Hyperventilation | 8.5 | 2.7 |
| Metabolism and nutrition disorders | | |
| Appetite decreased | 9.5 | 3.8 |
Musculoskeletal and connective tissue disorders | | |
| Muscle twitching | 7.4 | 2.7 |
| Vascular disorders | | |
| Hot flushes | 5.9 | 2.7 |
There have also been reports of withdrawal seizures upon rapid decrease or abrupt discontinuation of alprazolam (see WARNINGS).
To discontinue treatment in patients taking alprazolam extended-release tablets, the dosage should be reduced slowly in keeping with good medical practice. It is suggested that the daily dosage of alprazolam extended-release tablets be decreased by no more than 0.5 mg every three days (see DOSAGE AND ADMINISTRATION). Some patients may benefit from an even slower dosage reduction. In a controlled postmarketing discontinuation study of panic disorder patients which compared this recommended taper schedule with a slower taper schedule, no difference was observed between the groups in the proportion of patients who tapered to zero dose; however, the slower schedule was associated with a reduction in symptoms associated with a withdrawal syndrome.
As with all benzodiazepines, paradoxical reactions such as stimulation, increased muscle spasticity, sleep disturbances, hallucinations, and other adverse behavioral effects such as agitation, rage, irritability, and aggressive or hostile behavior have been reported rarely. In many of the spontaneous case reports of adverse behavioral effects, patients were receiving other CNS drugs concomitantly and/or were described as having underlying psychiatric conditions. Should any of the above events occur, alprazolam should be discontinued. Isolated published reports involving small numbers of patients have suggested that patients who have borderline personality disorder, a prior history of violent or aggressive behavior, or alcohol or substance abuse may be at risk for such events. Instances of irritability, hostility, and intrusive thoughts have been reported during discontinuation of alprazolam in patients with posttraumatic stress disorder.