Clonazepam Prescribing Information
• Reserve concomitant prescribing of these drugs in patients for whom alternative treatment options are inadequate.
• Limit dosages and durations to the minimum required.
• Follow patients for signs and symptoms of respiratory depression and sedation (see WARNINGS and PRECAUTIONS).
• The use of benzodiazepines, including clonazepam orally disintegrating tablets, exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. Abuse and misuse of benzodiazepines commonly involve concomitant use of other medications, alcohol, and/or illicit substances, which is associated with an increased frequency of serious adverse outcomes. Before prescribing clonazepam orally disintegrating tablets and throughout treatment, assess each patient’s risk for abuse, misuse, and addiction (see WARNINGS).
• The continued use of benzodiazepines, including clonazepam orally disintegrating tablets, may lead to clinically significant physical dependence. The risks of dependence and withdrawal increase with longer treatment duration and higher daily dose. Abrupt discontinuation or rapid dosage reduction of clonazepam orally disintegrating tablets after continued use may precipitate acute withdrawal reactions, which can be life-threatening. To reduce the risk of withdrawal reactions, use a gradual taper to discontinue clonazepam orally disintegrating tablets or reduce the dosage (see DOSAGE AND ADMINISTRATION and WARNINGS).
In some studies, up to 30% of patients have shown a loss of anticonvulsant activity, often within 3 months of administration. In some cases, dosage adjustment may reestablish efficacy.
The efficacy of clonazepam orally disintegrating tablets was established in two 6- to 9-week trials in panic disorder patients whose diagnoses corresponded to the DSM-IIIR category of panic disorder (see CLINICAL PHARMACOLOGY:
Panic disorder (DSM-V) is characterized by recurrent unexpected panic attacks, ie, a discrete period of intense fear or discomfort in which four (or more) of the following symptoms develop abruptly and reach a peak within 10 minutes: (1) palpitations, pounding heart or accelerated heart rate; (2) sweating; (3) trembling or shaking; (4) sensations of shortness of breath or smothering; (5) feeling of choking; (6) chest pain or discomfort; (7) nausea or abdominal distress; (8) feeling dizzy, unsteady, lightheaded or faint; (9) derealization (feelings of unreality) or depersonalization (being detached from oneself); (10) fear of losing control; (11) fear of dying; (12) paresthesias (numbness or tingling sensations); (13) chills or hot flushes.
The effectiveness of clonazepam orally disintegrating tablets in long-term use, that is, for more than 9 weeks, has not been systematically studied in controlled clinical trials. The physician who elects to use clonazepam orally disintegrating tablets for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient (see DOSAGE AND ADMINISTRATION).
Clonazepam is available as an orally disintegrating tablet. The orally disintegrating tablet should be administered as follows: After opening the carton, peel back the foil on the blister. Do not push tablet through foil. Immediately upon opening the blister, using dry hands, remove the tablet and place it in the mouth. Tablet disintegration occurs rapidly in saliva so it can be easily swallowed with or without water.
The use of multiple anticonvulsants may result in an increase of depressant adverse effects. This should be considered before adding clonazepam orally disintegrating tablets to an existing anticonvulsant regimen.
Treatment should be discontinued gradually, with a decrease of 0.125 mg bid every 3 days, until the drug is completely withdrawn.
There is no body of evidence available to answer the question of how long the patient treated with clonazepam should remain on it. Therefore, the physician who elects to use clonazepam orally disintegrating tablets for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient.
To reduce the risk of withdrawal reactions, increased seizure frequency, and status
epilepticus, use a gradual taper to discontinue clonazepam orally disintegrating tablets orreduce the dosage. If a patient develops withdrawal reactions, consider pausing the taper orincreasing the dosage to the previous tapered dosage level. Subsequently decrease the dosagemore slowly (see WARNINGS:Clonazepam orally disintegrating tablets are contraindicated in patients with the following conditions:
- History of sensitivity to benzodiazepines
- Clinical or biochemical evidence of significant liver disease
- Acute narrow angle glaucoma (it may be used in patients with open angle glaucoma who are receiving appropriate therapy).
The adverse experiences for clonazepam orally disintegrating tablets are provided separately for patients with seizure disorders and with panic disorder.
The stated frequencies of adverse events represent the proportion of individuals who experienced, at least once, a treatment-emergent adverse event of the type listed. An event was considered treatment-emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation.
Overall, the incidence of discontinuation due to adverse events was 17% in clonazepam orally disintegrating tablets compared to 9% for placebo in the combined data of two 6-to 9-week trials. The most common events (≥1%) associated with discontinuation and a dropout rate twice or greater for clonazepam orally disintegrating tablets than that of placebo included the following:
Adverse Event | Clonazepam Orally Disintegrating Tablets (N=574) | Placebo (N=294) |
| Somnolence | 7% | 1% |
| Depression | 4% | 1% |
| Dizziness | 1% | <1% |
| Nervousness | 1% | 0% |
| Ataxia | 1% | 0% |
| Intellectual Ability Reduced | 1% | 0% |
Table 3 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse events that occurred during acute therapy of panic disorder from a pool of two 6- to 9-week trials. Events reported in 1% or more of patients treated with clonazepam orally disintegrating tablets (doses ranging from 0.5 to 4 mg/day) and for which the incidence was greater than that in placebo-treated patients are included.
The prescriber should be aware that the figures in Table 3 cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those that prevailed in the clinical trials. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses and investigators. The cited figures, however, do provide the prescribing physician with some basis for estimating the relative contribution of drug and nondrug factors to the side effect incidence in the population studied.
Clonazepam Maximum Daily Dose | ||||||
Adverse Event by Body System | < 1mg n=96 % | 1 to <2mg n=129 % | 2 to <3mg n=113 % | ≥ 3mg n=235 % | All Clonazepam Orally Disintegrating Tablets Groups N=574 % | Placebo N=294 % |
| Central & Peripheral Nervous System | ||||||
| Somnolence† | 26 | 35 | 50 | 36 | 37 | 10 |
| Dizziness | 5 | 5 | 12 | 8 | 8 | 4 |
| Coordination Abnormal† | 1 | 2 | 7 | 9 | 6 | 0 |
| Ataxia† | 2 | 1 | 8 | 8 | 5 | 0 |
| Dysarthria† | 0 | 0 | 4 | 3 | 2 | 0 |
| Psychiatric | ||||||
| Depression | 7 | 6 | 8 | 8 | 7 | 1 |
| Memory Disturbance | 2 | 5 | 2 | 5 | 4 | 2 |
| Nervousness | 1 | 4 | 3 | 4 | 3 | 2 |
| Intellectual Ability Reduced | 0 | 2 | 4 | 3 | 2 | 0 |
| Emotional Lability | 0 | 1 | 2 | 2 | 1 | 1 |
| Libido Decreased | 0 | 1 | 3 | 1 | 1 | 0 |
| Confusion | 0 | 2 | 2 | 1 | 1 | 0 |
| Respiratory System | | | | | | |
| Upper Respiratory Tract Infection† | 10 | 10 | 7 | 6 | 8 | 4 |
| Sinusitis | 4 | 2 | 8 | 4 | 4 | 3 |
| Rhinitis | 3 | 2 | 4 | 2 | 2 | 1 |
| Coughing | 2 | 2 | 4 | 0 | 2 | 0 |
| Pharyngitis | 1 | 1 | 3 | 2 | 2 | 1 |
| Bronchitis | 1 | 0 | 2 | 2 | 1 | 1 |
| Gastrointestinal System | | | | | | |
| Constipation† | 0 | 1 | 5 | 3 | 2 | 2 |
| Appetite Decreased | 1 | 1 | 0 | 3 | 1 | 1 |
| Abdominal Pain† | 2 | 2 | 2 | 0 | 1 | 1 |
| Body as a Whole | | | | | | |
| Fatigue | 9 | 6 | 7 | 7 | 7 | 4 |
| Allergic Reaction | 3 | 1 | 4 | 2 | 2 | 1 |
| Musculoskeletal | | | | | | |
| Myalgia | 2 | 1 | 4 | 0 | 1 | 1 |
| Resistance Mechanism Disorders | | | | | | |
| Influenza | 3 | 2 | 5 | 5 | 4 | 3 |
| Urinary System | | | | | | |
| Micturition Frequency | 1 | 2 | 2 | 1 | 1 | 0 |
| Urinary Tract Infection† | 0 | 0 | 2 | 2 | 1 | 0 |
| Vision Disorders | | | | | | |
| Blurred Vision | 1 | 2 | 3 | 0 | 1 | 1 |
| Reproductive Disorders‡ | | | | | | |
| Female | | | | | | |
| Dysmenorrhea | 0 | 6 | 5 | 2 | 3 | 2 |
| Colpitis | 4 | 0 | 2 | 1 | 1 | 1 |
| Male | | | | | | |
| Ejaculation Delayed | 0 | 0 | 2 | 2 | 1 | 0 |
| Impotence | 3 | 0 | 2 | 1 | 1 | 0 |
* Events reported by at least 1% of patients treated with clonazepam orally disintegrating tablets and for which the incidence was greater than that for placebo.
† Indicates that the p-value for the dose-trend test (Cochran-Mantel-Haenszel) for adverse event incidence was ≤0.1.
‡ Denominators for events in gender-specific systems are: n=240 (clonazepam), 102 (placebo) for male, and 334 (clonazepam), 192 (placebo) for female.
Adverse Event | Clonazepam (N=574) | Placebo (N=294) |
| Somnolence | 37% | 10% |
| Depression | 7% | 1% |
| Coordination Abnormal | 6% | 0% |
| Ataxia | 5% | 0% |
* Treatment-emergent events for which the incidence in the clonazepam patients was ≥5% and at least twice that in the placebo patients.
In the pool of two short-term placebo-controlled trials, adverse events classified under the preferred term “depression” were reported in 7% of clonazepam orally disintegrating tablets-treated patients compared to 1% of placebo-treated patients, without any clear pattern of dose relatedness. In these same trials, adverse events classified under the preferred term “depression” were reported as leading to discontinuation in 4% of clonazepam orally disintegrating tablets-treated patients compared to 1% of placebo-treated patients. While these findings are noteworthy, Hamilton Depression Rating Scale (HAM-D) data collected in these trials revealed a larger decline in HAM-D scores in the clonazepam group than the placebo group suggesting that clonazepam-treated patients were not experiencing a worsening or emergence of clinical depression.
Following is a list of modified CIGY terms that reflect treatment-emergent adverse events reported by patients treated with clonazepam orally disintegrating tablets at multiple doses during clinical trials. All reported events are included except those already listed in Table 3 or elsewhere in labeling, those events for which a drug cause was remote, those event terms which were so general as to be uninformative, and events reported only once and which did not have a substantial probability of being acutely life-threatening. It is important to emphasize that, although the events occurred during treatment with clonazepam orally disintegrating tablets, they were not necessarily caused by it.
Events are further categorized by body system and listed in order of decreasing frequency. These adverse events were reported infrequently, which is defined as occurring in 1/100 to 1/1000 patients.
In a study in which the 2 mg clonazepam orally disintegrating tablet was administered with and without propantheline (an anticholinergic agent with multiple effects on the GI tract) to healthy volunteers, the AUC of clonazepam was 10% lower and the Cmax of clonazepam was 20% lower when the orally disintegrating tablet was given with propantheline compared to when it was given alone.
Fluoxetine does not affect the pharmacokinetics of clonazepam. Cytochrome P-450 inducers, such as phenytoin, carbamazepine and phenobarbital, induce clonazepam metabolism, causing an approximately 30% decrease in plasma clonazepam levels. Although clinical studies have not been performed, based on the involvement of the cytochrome P-450 3A family in clonazepam metabolism, inhibitors of this enzyme system, notably oral antifungal agents, should be used cautiously in patients receiving clonazepam.