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Klonopin Side Effects

Generic name: clonazepam

Medically reviewed by Drugs.com. Last updated on Oct 30, 2023.

Note: This document contains side effect information about clonazepam. Some dosage forms listed on this page may not apply to the brand name Klonopin.

Applies to clonazepam: oral tablet, oral tablet disintegrating.

Warning

Oral route (Tablet)

Risks From Concomitant Use With Opioids; Abuse, Misuse, and Addiction; and Dependence and Withdrawal Reactions:Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, 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. Follow patients for signs and symptoms of respiratory depression and sedation.The use of benzodiazepines, including clonazepam, 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 and throughout treatment, assess each patient's risk for abuse, misuse, and addiction.The continued use of benzodiazepines, including clonazepam, 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 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 or reduce the dosage.

Oral route (Tablet, Disintegrating)

Risks From Concomitant Use With Opioids; Abuse, Misuse, and Addiction; and Dependence and Withdrawal Reactions:Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, 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. Follow patients for signs and symptoms of respiratory depression and sedation.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.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.

Serious side effects of Klonopin

Along with its needed effects, clonazepam (the active ingredient contained in Klonopin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking clonazepam:

More common

Less common

Rare

Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur while taking clonazepam:

Symptoms of overdose

Other side effects of Klonopin

Some side effects of clonazepam may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Rare

Incidence not known

For Healthcare Professionals

Applies to clonazepam: oral tablet, oral tablet disintegrating.

General

The most commonly reported side effects included drowsiness, somnolence, ataxia, and behavior problems.[Ref]

Nervous system

Reversible ataxia, dysarthria, anterograde amnesia, and nystagmus may occur, especially in long-term treatment and/or at high doses.

Transient somnolence, dizziness, ataxia, lightheadedness, muscular hypotonia, and/or coordination disturbances may occur, and usually disappear spontaneously when treatment is continued or upon dose reductions.[Ref]

Very common (10% or more): Drowsiness (up to 50%), somnolence (up to 50%), ataxia (up to 30%), dizziness (up to 12%)

Common (1% to 10%): Abnormal coordination, dysarthria, intellectual ability reduced, memory disturbance, nystagmus

Rare (0.01% to 0.1%): Convulsions, headache

Very rare (less than 0.01%): Generalized fits, lightheadedness

Frequency not reported: Activation of new types of seizures, amnestic effects, anterograde amnesia/amnesia, aphonia, attention lack, coma, coordination disturbances, decreased movement and gait coordination, disturbance in attention, dysdiadochokinesis/inability to perform rapid, alternating movements, dysphagia, epileptic seizures, extremity numbness and tingling, forgetfulness, head fullness, hemiparesis, hyperactivity, hyperphagia, hypersensitivity to light/noise/physical contact, hypertonia, hypoesthesia, impaired concentration/poor concentration, lethargy, migraine, motion sickness, muscular hypotonia, paresis, paresthesia, seizures, speech slowing/slurring, taste loss, tremor, vertigo, visual field defect

Postmarketing reports: Choreiform movements, hypotonia, preexisting brain damage[Ref]

Psychiatric

Very common (10% or more): Behavior problems (up to 25%)

Common (1% to 10%): Confusion/confusional state, decreased libido, depression, emotional lability, nervousness

Rare (0.01% to 0.1%): Decrease in sexual drive, loss of libido

Frequency not reported: Aggressive behavior/aggressive reaction/aggression/aggressiveness, agitation, anger, anxiety, apathy, depersonalization, derealization, disorientation, drug withdrawal symptoms, dysphoria, excessive dreaming, excitability/excitement, extreme anxiety, feeling mad, hallucinations, hostility, hysteria, illusion, inappropriate behavior, increased libido, insomnia, irritability, nightmares, organic disinhibition, physical dependence, psychological dependence, psychosis, psychotic disorders, restlessness, sleep disorder, sleep disturbance, suicidal attempt, suicide ideation, tension, vivid dreams, worsening/emergence of clinical depression

Postmarketing reports: Abnormal dreams, change in libido, dependence, encopresis[Ref]

Reversible inappropriate behavior may occur, especially in long-term treatment and/or at high doses.[Ref]

Respiratory

Very common (10% or more): Upper respiratory tract infection (up to 10%)

Common (1% to 10%): Bronchitis, coughing, pharyngitis, rhinitis, sinusitis

Rare (0.01% to 0.1%): Respiratory depression

Frequency not reported: Asthmatic attach, bronchial hypersecretion/hypersecretion in upper respiratory passages, chest congestion, dyspnea, excessive sneezing, hoarseness, mucus obstruction of the nasopharynx, nosebleed, pneumonia, rhinorrhea, shortness of breath, yawning

Postmarketing reports: Airway obstruction, pharyngeal edema[Ref]

Genitourinary

Common (1% to 10%): Colpitis, dysmenorrhea, ejaculation delayed, impotence, micturition frequency, urinary tract infection

Rare (0.01% to 0.1%): Erectile dysfunction, urinary incontinence

Frequency not reported: Bladder dysfunction, breast pain, dysuria, ejaculation decreased, enuresis/feeling of enuresis, menstrual irregularity, nocturia, pain pelvic, polyuria, urinary retention, urinary tract bleeding, urine discoloration[Ref]

Other

Transient fatigue, lassitude, slowed reaction, and/or tiredness may occur, and usually disappear spontaneously when treatment is continued or upon dose reductions.[Ref]

Common (1% to 10%): Fatigue, lassitude, tiredness

Frequency not reported: Accident, drunkenness, earache, fever, herpes simplex infection, hyperacusis, injury, malaise, otitis, pain, paradoxical reaction, reaction slowed/decreased, shivering, thirst, wound

Postmarketing reports: Falls, general deterioration[Ref]

Gastrointestinal

Common (1% to 10%): Abdominal pain, constipation

Rare (0.01% to 0.1%): Epigastric discomfort/symptoms, gastrointestinal symptoms, nausea

Frequency not reported: Abdominal discomfort, bowel movements frequent, coated tongue, dyspepsia, flatulence, gastrointestinal inflammation, hemorrhoids, pyrosis, salivary hypersecretion/saliva increased/hypersalivation, stomach upset, tongue thick, toothache, tooth disorder, vomiting

Postmarketing reports: Diarrhea, dry mouth, gastritis, sore gums[Ref]

Musculoskeletal

Common (1% to 10%): Muscle weakness, myalgia

Frequency not reported: Ankle pain, arthralgia, back pain, foot pain, fracture traumatic, knee pain, knee swelling, jaw pain, leg cramps, leg pain, lumbago, muscle cramps, muscle pain, nape pain, shoulder pain, sprains, strains, tendinitis, twitching

Postmarketing reports: Fractures[Ref]

Hypersensitivity

Common (1% to 10%): Allergic reaction

Rare (0.01% to 0.1%): Angioedema

Frequency not reported: Anaphylaxis[Ref]

Ocular

Common (1% to 10%): Blurred vision

Frequency not reported: Diplopia/double vision, eye irritation, eye twitching, periorbital edema, stye, visual disturbance, xerophthalmia

Postmarketing reports: Abnormal eye movements, "glassy-eyed" appearance[Ref]

Reversible vision disorders (e.g., diplopia) may occur, especially in long-term treatment and/or at high doses.[Ref]

Metabolic

Common (1% to 10%): Appetite decreased

Frequency not reported: Anorexia, dehydration, gout, hunger abnormal, increased appetite, weight gain, weight loss[Ref]

Immunologic

Common (1% to 10%): Influenza

Frequency not reported: Infection mycotic, infection streptococcal, infection viral, moniliasis[Ref]

Dermatologic

Rare (0.01% to 0.1%): Pigmentation changes, pruritus, rash/skin rash, transient hair loss, urticaria

Frequency not reported: Abrasions, acne flare, alopecia/transient hair loss, bleeding dermal, burning skin, cellulitis, dermatitis contact, facial edema, hair loss, hirsutism, pustular reaction, skin disorder, sweating, xeroderma

Postmarketing reports: Angioneurotic edema, pigmentation disorder[Ref]

Hematologic

Rare (0.01% to 0.1%): Decreased platelet count

Frequency not reported: Anemia, blood dyscrasias, eosinophilia, infectious mononucleosis, leukopenia, lymphadenopathy

Postmarketing reports: Thrombocytopenia[Ref]

Cardiovascular

Tachycardia occurred after IV administration.[Ref]

Frequency not reported: Ankle edema, chest pain, edema, flushing, foot edema, palpitations, postural hypotension, tachycardia, thrombophlebitis leg

Postmarketing reports: Cardiac arrest, cardiac failure, thrombophlebitis, thrombosis[Ref]

Hepatic

Frequency not reported: Abnormal liver function tests, hepatomegaly

Postmarketing reports: Transient elevations of serum transaminases and alkaline phosphatase[Ref]

Endocrine

Frequency not reported: Incomplete precocious puberty/premature secondary sex characteristics[Ref]

Local

Frequency not reported: Localized inflammation[Ref]

Renal

Frequency not reported: Cystitis[Ref]

Frequently asked questions

References

1. Product Information. Klonopin (clonazepam). Roche Laboratories. 2001;PROD.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.