CLONAZEPAM- clonazepam_tablet
Function and Efficacy
The precise mechanism by which clonazepam exerts its antiseizure and antipanic effects is unknown, although it is believed to be related to its ability to enhance the activity of gamma aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Clonazepam is rapidly and completely absorbed after oral administration. The absolute bioavailability of clonazepam is about 90%. Maximum plasma concentrations of clonazepam are reached within 1 to 4 hours after oral administration. Clonazepam is approximately 85% bound to plasma proteins. Clonazepam is highly metabolized, with less than 2% unchanged clonazepam being excreted in the urine. Biotransformation occurs mainly by reduction of the 7-nitro group to the 4-amino derivative. This derivative can be acetylated, hydroxylated and glucuronidated. Cytochrome P-450 including CYP3A, may play an important role in clonazepam reduction and oxidation. The elimination half-life of clonazepam is typically 30 to 40 hours. Clonazepam pharmacokinetics are dose-independent throughout the dosing range. There is no evidence that clonazepam induces its own metabolism or that of other drugs in humans. Controlled studies examining the influence of gender and age on clonazepam pharmacokinetics have not been conducted, nor have the effects of renal or liver disease on clonazepam pharmacokinetics been studied. Because clonazepam undergoes hepatic metabolism, it is possible that liver disease will impair clonazepam elimination. Thus, caution should be exercised when administering clonazepam to these patients (see CONTRAINDICATIONS In children, clearance values of 0. 32 mL/min/kg (ages 2 to 18 years) and 0. 4 mL/min/kg (ages 7 to 12 years) were reported; these values decreased with increasing body weight. Ketogenic diet in children does not affect clonazepam concentrations. The effectiveness of clonazepam in the treatment of panic disorder was demonstrated in two double-blind, placebo-controlled studies of adult outpatients who had a primary diagnosis of panic disorder (DSM-IIIR) with or without agoraphobia. In these studies, clonazepam was shown to be significantly more effective than placebo in treating panic disorder on change from baseline in panic attack frequency, the Clinician’s Global Impression Severity of Illness Score and the Clinician’s Global Impression Improvement Score. Study 1 was a 9-week, fixed-dose study involving clonazepam doses of 0. 5, 1, 2, 3 or 4 mg/day or placebo. This study was conducted in four phases: a 1-week placebo lead-in, a 3-week upward titration, a 6-week fixed dose, and a 7-week discontinuance phase. A significant difference from placebo was observed consistently only for the 1 mg/day group. The difference between the 1 mg dose group and placebo in reduction from baseline in the number of full panic attacks was approximately 1 panic attack per week. At endpoint, 74% of patients receiving clonazepam 1 mg/day were free of full panic attacks, compared to 56% of placebo-treated patients. Study 2 was a 6-week, flexible-dose study involving clonazepam in a dose range of 0. 5 to 4 mg/day or placebo. This study was conducted in three phases: a 1-week placebo lead-in, a 6-week optimal-dose, and a 6-week discontinuance phase. The mean clonazepam dose during the optimal dosing period was 2. The difference between clonazepam and placebo in reduction from baseline in the number of full panic attacks was approximately 1 panic attack per week. At endpoint, 62% of patients receiving clonazepam were free of full panic attacks, compared to 37% of placebo-treated patients. Subgroup analyses did not indicate that there were any differences in treatment outcomes as a function of race or gender.
Indication
Seizure Disorders: Some loss of effect may occur during the course of clonazepam treatment (see PRECAUTIONS : Loss of Effect Panic Disorder: The efficacy of clonazepam 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: Clinical Trials Panic disorder (DSM-V) is characterized by recurrent unexpected panic attacks, i.e., 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 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 tablets for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient (see DOSAGE AND ADMINISTRATION
Usage and Dosage
Clonazepam is available as tablets. The tablets should be administered with water by swallowing the tablet whole. The use of multiple anticonvulsants may result in an increase of CNS depressant adverse effects. This should be considered before adding clonazepam to an existing anticonvulsant regimen. The initial dose for adults with seizure disorders should not exceed 1. 5 mg/day divided into three doses. Dosage may be increased in increments of 0. 5 to 1 mg every 3 days until seizures are adequately controlled or until side effects preclude any further increase. Maintenance dosage must be individualized for each patient depending upon response. Maximum recommended daily dose is 20 mg. Clonazepam is administered orally. In order to minimize drowsiness, the initial dose for infants and children (up to 10 years of age or 30 kg of body weight) should be between 0. 03 mg/kg/day but not to exceed 0. 05 mg/kg/day given in two or three divided doses. Dosage should be increased by no more than 0. 5 mg every third day until a daily maintenance dose of 0. 2 mg/kg of body weight has been reached, unless seizures are controlled or side effects preclude further increase. Whenever possible, the daily dose should be divided into three equal doses. If doses are not equally divided, the largest dose should be given before retiring. There is no clinical trial experience with clonazepam in seizure disorder patients 65 years of age and older. In general, elderly patients should be started on low doses of clonazepam and observed closely (see PRECAUTIONS: Geriatric Use The initial dose for adults with panic disorder is 0. 25 mg twice daily. An increase to the target dose for most patients of 1 mg/day may be made after 3 days. The recommended dose of 1 mg/day is based on the results from a fixed dose study in which the optimal effect was seen at 1 mg/day. Higher doses of 2, 3 and 4 mg/day in that study were less effective than the 1 mg/day dose and were associated with more adverse effects. Nevertheless, it is possible that some individual patients may benefit from doses of up to a maximum dose of 4 mg/day, and in those instances, the dose may be increased in increments of 0. 25 mg twice daily every 3 days until panic disorder is controlled or until side effects make further increases undesired. To reduce the inconvenience of somnolence, administration of one dose at bedtime may be desirable. Treatment should be discontinued gradually, with a decrease of 0. 125 mg twice daily 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 for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient. There is no clinical trial experience with clonazepam in panic disorder patients under 18 years of age. There is no clinical trial experience with clonazepam in panic disorder patients 65 years of age and older. In general, elderly patients should be started on low doses of clonazepam and observed closely (see PRECAUTIONS: Geriatric Use To reduce the risk of withdrawal reactions, increased seizure frequency, and status epilepticus, use a gradual taper to discontinue clonazepam tablets or reduce the dosage. If a patient develops withdrawal reactions, consider pausing the taper or increasing the dosage to the previous tapered dosage level. Subsequently decrease the dosage more slowly (see WARNINGS: Dependence and Withdrawal Reactions DRUG ABUSE AND DEPENDENCE: Dependence.
Label
Adverse Reactions
The adverse experiences for clonazepam are provided separately for patients with seizure disorders and with panic disorder. The most frequently occurring side effects of clonazepam are referable to CNS depression. Experience in treatment of seizures has shown that drowsiness has occurred in approximately 50% of patients and ataxia in approximately 30%. In some cases, these may diminish with time; behavior problems have been noted in approximately 25% of patients. Others, listed by system, including those identified during postapproval use of clonazepam are: Cardiovascular: Dermatologic: Gastrointestinal: Genitourinary: Hematopoietic: Hepatic: Musculoskeletal: Miscellaneous: Neurologic: Psychiatric: The following paradoxical reactions have been observed: irritability, aggression, agitation, nervousness, hostility, anxiety, sleep disturbances, nightmares, abnormal dreams, hallucinations. Respiratory: Adverse events during exposure to clonazepam were obtained by spontaneous report and recorded by clinical investigators using terminology of their own choosing. Consequently, it is not possible to provide a meaningful estimate of the proportion of individuals experiencing adverse events without first grouping similar types of events into a smaller number of standardized event categories. In the tables and tabulations that follow, CIGY dictionary terminology has been used to classify reported adverse events, except in certain cases in which redundant terms were collapsed into more meaningful terms, as noted below. 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 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 than that of placebo included the following: Table 2: Most Common Adverse Events (>=1%) Associated with Discontinuation of Treatment Adverse Event Clonazepam (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 The prescriber should be aware that the figures in Table 3 Table 3: Treatment-Emergent Adverse Event Incidence in 6-to 9-Week Placebo-Controlled Clinical Trials* Clonazepam Maximum Daily Dose Adverse Event by Body System <1 mg n=96 % 1 to <2 mg n=129 % 2 to <3 mg n=113 % >=3 mg n=235 % All Clonazepam Groups N=574 % Placebo N = 294 % Central & Peripheral Nervous System Somnolence dagger 26 35 50 36 37 10 Dizziness 5 5 12 8 8 4 Coordination Abnormal dagger 1 2 7 9 6 0 Ataxia dagger 2 1 8 8 5 0 Dysarthria dagger 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 dagger 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 dagger 0 1 5 3 2 2 Appetite Decreased 1 1 0 3 1 1 Abdominal Pain dagger 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 Infectiondagger 0 0 2 2 1 0 Vision Disorders Blurred Vision 1 2 3 0 1 1 Reproductive Disorders double dagger 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 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. double dagger. Denominators for events in gender-specific systems are: n=240 (clonazepam), 102 (placebo) for male, and 334 (clonazepam), 192 (placebo) for female. Table 4: Incidence of Most Commonly Observed Adverse Events* in Acute Therapy in Pool of 6- to 9-Week Trials Adverse Event Clonazepam Placebo 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-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-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 at multiple doses during clinical trials. All reported events are included except those already listed in Table 3 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. Body as a Whole: Cardiovascular Disorders: Central and Peripheral Nervous System Disorders: Gastrointestinal System Disorders: Hearing and Vestibular Disorders: Heart Rate and Rhythm Disorders: Metabolic and Nutritional Disorders: Musculoskeletal System Disorders: Platelet, Bleeding and Clotting Disorders: Psychiatric Disorders: Reproductive Disorders, Female: Reproductive Disorders, Male: Resistance Mechanism Disorders: Respiratory System Disorders: Skin and Appendages Disorders: Special Senses Other, Disorders: Urinary System Disorders: Vascular (Extracardiac) Disorders: Vision Disorders: To report SUSPECTED ADVERSE REACTIONS, contact Teva at 1-888-838-2872 of FDA-1088 or http://www. gov/medwatch.
Other Information
Overdosage of benzodiazepines is characterized by central nervous system depression ranging from drowsiness to coma. In mild to moderate cases, symptoms can include drowsiness, confusion, dysarthria, lethargy, hypnotic state, diminished reflexes, ataxia, and hypotonia. Rarely, paradoxical or disinhibitory reactions (including agitation, irritability, impulsivity, violent behavior, confusion, restlessness, excitement, and talkativeness) may occur. In severe overdosage cases, patients may develop respiratory depression and coma. Overdosage of benzodiazepines in combination with other CNS depressants (including alcohol and opioids) may be fatal (see WARNINGS: Abuse, Misuse, and Addiction In managing benzodiazepine overdosage, employ general supportive measures, including intravenous fluids and airway maintenance. Flumazenil, a specific benzodiazepine receptor antagonist indicated for the complete or partial reversal of the sedative effects of benzodiazepines in the management of benzodiazepine overdosage, can lead to withdrawal and adverse reactions, including seizures, particularly in the context of mixed overdosage with drugs that increase seizure risk (e.g., tricyclic and tetracyclic antidepressants) and in patients with long-term benzodiazepine use and physical dependency. The risk of withdrawal seizures with flumazenil use may be increased in patients with epilepsy. Flumazenil is contraindicated in patients who have received a benzodiazepine for control of a potentially life-threatening condition (e.g., status epilepticus). If the decision is made to use flumazenil, it should be used as an adjunct to, not as a substitute for, supportive management of benzodiazepine overdosage. See the flumazenil injection Prescribing Information. Consider contacting the Poison Help line (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations.
Manufacturer
REMEDYREPACK INC.