Clonazepam Side Effects

Brand Names: Klonopin Wafer, Klonopin

Please note - some side effects for Clonazepam may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Clonazepam - for the Consumer

Clonazepam

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Clonazepam:

Clumsiness or unsteadiness; constipation; cough; dizziness; drowsiness; dry mouth; headache; increased saliva production; lightheadedness; loss of appetite; muscle aches; nervousness; runny nose; tiredness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); behavior changes; blurred vision or other vision changes; change in the amount of urine produced; confusion; dark urine; fever, chills, or sore throat; hallucinations; hostility; irregular heartbeat; memory loss or problems; mental or mood changes (eg, agitation, aggression, anxiety; depression, hostility, irritability); new or worsening seizures; painful menstrual periods; painful urination; severe drowsiness; severe or persistent tiredness or weakness; shortness of breath; slow or shallow breathing; slurred speech or other speech problems; suicidal thoughts or actions; tremor; unusual bruising or bleeding; yellowing of the skin or eyes.

Clonazepam Orally Disintegrating Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Clonazepam Orally Disintegrating Tablets:

Clumsiness or unsteadiness; constipation; cough; dizziness; drowsiness; dry mouth; headache; increased saliva production; lightheadedness; loss of appetite; muscle aches; nervousness; runny nose; tiredness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); behavior changes; blurred vision or other vision changes; change in the amount of urine produced; confusion; dark urine; fever, chills, or sore throat; hallucinations; hostility; irregular heartbeat; memory loss or problems; mental or mood changes (eg, agitation, aggression, anxiety; depression, hostility, irritability); new or worsening seizures; painful menstrual periods; painful urination; severe drowsiness; severe or persistent tiredness or weakness; shortness of breath; slow or shallow breathing; slurred speech or other speech problems; suicidal thoughts or actions; tremor; unusual bruising or bleeding; yellowing of the skin or eyes.

Clonazepam Side Effects - for the Professional

Clonazepam

The adverse experiences for Clonazepam are provided separately for patients with seizure disorders and with panic disorder.

Seizure Disorders

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, are:

Neurologic: Abnormal eye movements, aphonia, choreiform movements, coma, diplopia, dysarthria, dysdiadochokinesis, “glassy-eyed” appearance, headache, hemiparesis, hypotonia, nystagmus, respiratory depression, slurred speech, tremor, vertigo

Psychiatric: Confusion, depression, amnesia, hallucinations, hysteria, increased libido, insomnia, psychosis, suicidal attempt (the behavior effects are more likely to occur in patients with a history of psychiatric disturbances). The following paradoxical reactions have been observed: excitability, irritability, aggressive behavior, agitation, nervousness, hostility, anxiety, sleep disturbances, nightmares and vivid dreams

Respiratory: Chest congestion, rhinorrhea, shortness of breath, hypersecretion in upper respiratory passages

Cardiovascular: Palpitations

Dermatologic: Hair loss, hirsutism, skin rash, ankle and facial edema

Gastrointestinal: Anorexia, coated tongue, constipation, diarrhea, dry mouth, encopresis, gastritis, increased appetite, nausea, sore gums

Genitourinary: Dysuria, enuresis, nocturia, urinary retention

Musculoskeletal: Muscle weakness, pains

Miscellaneous: Dehydration, general deterioration, fever, lymphadenopathy, weight loss or gain

Hematopoietic: Anemia, leukopenia, thrombocytopenia, eosinophilia

Hepatic: Hepatomegaly, transient elevations of serum transaminases and alkaline phosphatase

Panic Disorder

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.

Adverse Findings Observed in Short-Term, Placebo-Controlled Trials

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 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 (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.

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 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, 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.

Body as a Whole: weight increase, accident, weight decrease, wound, edema, fever, shivering, abrasions, ankle edema, edema foot, edema periorbital, injury, malaise, pain, cellulitis, inflammation localized

Cardiovascular Disorders: chest pain, hypotension postural

Central and Peripheral Nervous System Disorders: migraine, paresthesia, drunkenness, feeling of enuresis, paresis, tremor, burning skin, falling, head fullness, hoarseness, hyperactivity, hypoesthesia, tongue thick, twitching

Gastrointestinal System Disorders: abdominal discomfort, gastrointestinal inflammation, stomach upset, toothache, flatulence, pyrosis, saliva increased, tooth disorder, bowel movements frequent, pain pelvic, dyspepsia, hemorrhoids

Hearing and Vestibular Disorders: vertigo, otitis, earache, motion sickness

Heart Rate and Rhythm Disorders: palpitation

Metabolic and Nutritional Disorders: thirst, gout

Musculoskeletal System Disorders: back pain, fracture traumatic, sprains and strains, pain leg, pain nape, cramps muscle, cramps leg, pain ankle, pain shoulder, tendinitis, arthralgia, hypertonia, lumbago, pain feet, pain jaw, pain knee, swelling knee

Platelet, Bleeding, and Clotting Disorders: bleeding dermal

Psychiatric Disorders: insomnia, organic disinhibition, anxiety, depersonalization, dreaming excessive, libido loss, appetite increased, libido increased, reactions decreased, aggressive reaction, apathy, attention lack, excitement, feeling mad, hunger abnormal, illusion, nightmares, sleep disorder, suicide ideation, yawning

Reproductive Disorders, Female: breast pain, menstrual irregularity

Reproductive Disorders, Male: ejaculation decreased

Resistance Mechanism Disorders: infection mycotic, infection viral, infection streptococcal, herpes simplex infection, infectious mononucleosis, moniliasis

Respiratory System Disorders: sneezing excessive, asthmatic attack, dyspnea, nosebleed, pneumonia, pleurisy

Skin and Appendages Disorders: acne flare, alopecia, xeroderma, dermatitis contact, flushing, pruritus, pustular reaction, skin burns, skin disorder

Special Senses Other, Disorders: taste loss

Urinary System Disorders: dysuria, cystitis, polyuria, urinary incontinence, bladder dysfunction, urinary retention, urinary tract bleeding, urine discoloration

Vascular (Extracardiac) Disorders: thrombophlebitis leg

Vision Disorders: eye irritation, visual disturbance, diplopia, eye twitching, styes, visual field defect, xerophthalmia

Clonazepam Tablet, orally disintegrating

The adverse experiences for Clonazepam are provided separately for patients with seizure disorders and with panic disorder.

Seizure Disorders:

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, are:

 Abnormal eye movements, aphonia, choreiform movements, coma, diplopia, dysarthria, dysdiadochokinesis, "glassy-eyed" appearance, headache, hemiparesis, hypotonia, nystagmus, respiratory depression, slurred speech, tremor, vertigo.

 Confusion, depression, amnesia, hallucinations, hysteria, increased libido, insomnia, psychosis, suicidal attempt (the behavior effects are more likely to occur in patients with a history of psychiatric disturbances). The following paradoxical reactions have been observed: excitability, irritability, aggressive behavior, agitation, nervousness, hostility, anxiety, sleep disturbances, nightmares and vivid dreams.

 Chest congestion, rhinorrhea, shortness of breath, hypersecretion in upper respiratory passages.

 Palpitations.

 Hair loss, hirsutism, skin rash, ankle and facial edema.

 Anorexia, coated tongue, constipation, diarrhea, dry mouth, encopresis, gastritis, increased appetite, nausea, sore gums.

Dysuria, enuresis, nocturia, urinary retention.

Muscle weakness, pains.

Dehydration, general deterioration, fever, lymphadenopathy, weight loss or gain.

 Anemia, leukopenia, thrombocytopenia, eosinophilia.

Hepatomegaly, transient elevations of serum transaminases and alkaline phosphatase.

Panic Disorder:

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.

Adverse Findings Observed in Short-Term, Placebo-Controlled Trials:

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 1 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 (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 1 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.

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 1 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, 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.

 weight increase, accident, weight decrease, wound, edema, fever, shivering, abrasions, ankle edema, edema foot, edema periorbital, injury, malaise, pain, cellulitis, inflammation localized

chest pain, hypotension postural

migraine, paresthesia, drunkenness, feeling of enuresis, paresis, tremor, burning skin, falling, head fullness, hoarseness, hyperactivity, hypoesthesia, tongue thick, twitching

abdominal discomfort, gastrointestinal inflammation, stomach upset, toothache, flatulence, pyrosis, saliva increased, tooth disorder, bowel movements frequent, pain pelvic, dyspepsia, hemorrhoids

vertigo, otitis, earache, motion sickness

 palpitation

 thirst, gout

back pain, fracture traumatic, sprains and strains, pain leg, pain nape, cramps muscle, cramps leg, pain ankle, pain shoulder, tendinitis, arthralgia, hypertonia, lumbago, pain feet, pain jaw, pain knee, swelling knee

bleeding dermal

insomnia, organic disinhibition, anxiety, depersonalization, dreaming excessive, libido loss, appetite increased, libido increased, reactions decreased, aggressive reaction, apathy, attention lack, excitement, feeling mad, hunger abnormal, illusion, nightmares, sleep disorder, suicide ideation, yawning

breast pain, menstrual irregularity

ejaculation decreased

infection mycotic, infection viral, infection streptococcal, herpes simplex infection, infectious mononucleosis, moniliasis

sneezing excessive, asthmatic attack, dyspnea, nosebleed, pneumonia, pleurisy

acne flare, alopecia, xeroderma, dermatitis contact, flushing, pruritus, pustular reaction, skin burns, skin disorder

taste loss

 dysuria, cystitis, polyuria, urinary incontinence, bladder dysfunction, urinary retention, urinary tract bleeding, urine discoloration

 thrombophlebitis leg

eye irritation, visual disturbance, diplopia, eye twitching, styes, visual field defect, xerophthalmia

Side Effects by Body System

Nervous system

Nervous system side effects are common, particularly at the initiation of therapy and include drowsiness, fatigue, ataxia, confusion, depression, daytime anxiety, and amnesia. Nystagmus, diplopia, vertigo, headache, respiratory depression, tremor and slurred speech have also been reported less frequently.

Sedation may initially occur in up to 50% of treated patients. Ataxia may occur in 30% of patients. Five to 6% of patients treated with clonazepam for seizures may develop more frequent seizures or a new type of seizure disorder. Weakness and hypotonia have also been reported. A case report has suggested that clonazepam may induce Tourette's syndrome.

Psychiatric

Behavioral problems have been reported in as many as 30% of treated patients.

Psychiatric side effects have been reported and include behavioral disinhibition (particularly sexual disinhibition), depression, and rarely, psychosis and mania.

Other

Other side effects have included withdrawal symptoms (similar to those which may occur after withdrawal of barbiturates and alcohol) which have been reported after abrupt cessation of clonazepam. Specifically, seizures, agitation, restlessness, anxiety, delirium, psychosis, dysphoria, insomnia, tremor, abdominal cramps, vomiting, rash, and sweating have been reported to have occurred, especially after long-term therapy.

Genitourinary

In one study, anorgasmia occurred in 44% of patients treated with clonazepam while anorgasmia occurred in only 6% of patients treated with placebo.

Genitourinary side effects may include urinary incontinence, anorgasmia, ejaculatory delay, and erectile dysfunction.

Hematologic

Hematologic side effects including thrombocytopenia have been reported rarely.

Gastrointestinal

Gastrointestinal side effects including hypersalivation, diarrhea, constipation, nausea, increased appetite, and anorexia have been reported.

Respiratory

Respiratory side effects including bronchial hypersecretion have been reported.

Dermatologic

Dermatologic side effects have included cases of rashes associated with clonazepam therapy. A case of erythema multiforme associated with clonazepam therapy has also been reported.

Ocular

Clonazepam is contraindicated in patients with narrow angle glaucoma.

Ocular side effects including acute worsening of narrow angle glaucoma is possible with clonazepam therapy.

Metabolic

Metabolic side effects have included exacerbation of seizure disorders in some patients with acute intermittent porphyria. However, a case report has suggested that clonazepam may be beneficial in this setting as well.

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