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Klonopin Wafer Side Effects

Generic Name: clonazepam

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

For the Consumer

Applies to clonazepam: oral solution, oral tablet, oral tablet disintegrating

Along with its needed effects, clonazepam (the active ingredient contained in Klonopin Wafer) 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
  • Body aches or pain
  • chills
  • cough
  • difficulty breathing
  • discouragement
  • dizziness
  • ear congestion
  • feeling sad or empty
  • fever
  • headache
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • loss of voice
  • nasal congestion
  • poor coordination
  • runny nose
  • shakiness and unsteady walk
  • sleepiness or unusual drowsiness
  • sneezing
  • sore throat
  • tiredness
  • trouble concentrating
  • trouble sleeping
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual tiredness or weakness
Less common
  • Being forgetful
  • bladder pain
  • bloody or cloudy urine
  • change in speech
  • diarrhea
  • difficult, burning, or painful urination
  • frequent urge to urinate
  • general feeling of discomfort or illness
  • joint pain
  • loss of appetite
  • lower back or side pain
  • mood or mental changes
  • muscle aches and pains
  • nausea
  • nervousness
  • problems in urination or increase in the amount of urine
  • shivering
  • slurred speech
  • sore throat
  • sweating
  • trouble speaking
  • vomiting
  • Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • changes in skin color
  • chest pain or discomfort
  • cold sweats
  • colds
  • confusion
  • cough or hoarseness
  • difficulty with sleeping
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • excessive dreaming
  • excessive muscle tone
  • excitement
  • falling
  • fast, irregular, pounding, or racing heartbeat or pulse
  • feeling mad
  • feeling of unreality
  • flu-like symptoms
  • headache, severe and throbbing
  • lack of feeling or emotion
  • lack or loss of self-control
  • muscle stiffness
  • muscle tension or tightness
  • nightmares
  • pain, inflammation, or swelling in the calves, shoulders, or hands
  • pain or swelling in the arms or legs without any injury
  • pain, tenderness, or swelling of the foot or leg
  • partial or slight paralysis
  • scaling
  • sense of detachment from self or body
  • shakiness in the legs, arms, hands, or feet
  • skin rash
  • swelling around the eyes
  • swelling of the face, ankle, foot, or knees
  • thoughts of killing oneself changes in behavior
  • tightness in the chest
  • trembling or shaking of the hands or feet
  • uncaring
  • vision changes
Incidence not known
  • Abdominal pain or fullness
  • anxiety
  • black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • change in consciousness
  • chest congestion
  • difficulty with coordination
  • double vision
  • drowsiness
  • dry mouth
  • feeling that others are watching you or controlling your behavior
  • feeling that others can hear your thoughts
  • feeling, seeing, or hearing things that are not there
  • hyperventilation
  • irregular, fast, slow, or shallow breathing
  • irregular, twisting uncontrolled movement of the face, hands, arms, or legs
  • loss of interest or pleasure
  • loss of memory
  • loss of strength or energy
  • loss of voice
  • muscle weakness
  • pale or blue lips, fingernails, or skin
  • pinpoint red spots on the skin
  • problems with memory
  • restlessness
  • severe mood or mental changes
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • troubled breathing with exertion
  • uncontrolled eye movements
  • unusual behavior
  • unusual bleeding or bruising
  • unusual weakness
  • vivid dreams
  • weight loss or gain

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
  • Decreased interest in sexual intercourse
  • difficulty with swallowing
  • dryness or soreness of the throat
  • heavy bleeding
  • hives
  • inability to have or keep an erection
  • longer than usual time to ejaculation of semen
  • loss in sexual ability, desire, drive, or performance
  • pain or tenderness around the eyes and cheekbones
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • voice changes
  • Acid or sour stomach
  • ankle, knee, or great toe joint pain
  • belching
  • bleeding after defecation
  • blistering, burning, crusting, dryness, or flaking of the skin
  • bloated
  • blurred or loss of vision
  • change in color perception
  • cracks in the skin at the corners of the mouth
  • decrease or change in vision
  • difficulty moving
  • double vision
  • dryness of the eyes
  • earache
  • excess air or gas in stomach or intestines
  • feeling of constant movement of self or surroundings
  • feeling of warmth
  • frequent bowel movements
  • full feeling
  • hair loss or thinning of the hair
  • halos around lights
  • heartburn
  • increased watering of the mouth
  • indigestion
  • irregularities in menstruation
  • itching in the genital or other skin areas
  • itching, scaling, severe redness, soreness, or swelling of the skin
  • joint stiffness or swelling
  • leg or muscle cramps
  • loss of taste
  • night blindness
  • nosebleeds
  • overbright appearance of lights
  • pain in the breasts or pelvic area
  • pain in the leg, nape, or back
  • passing gas
  • red, sore eyes
  • redness of the face, neck, arms, and occasionally, upper chest
  • redness or swelling in the ear
  • sensation of spinning
  • smaller amount of semen ejaculated than usual
  • sore on the edge of the eyelid
  • soreness or redness around the fingernails and toenails
  • stomach discomfort, upset, or pain
  • thickening of the tongue
  • thirst
  • tooth disorder
  • toothache
  • tunnel vision
  • twitching of the eyes
  • uncomfortable swelling around the anus
  • worsening of acne
Incidence not known
  • Burning feeling in the chest or stomach
  • difficulty having a bowel movement (stool)
  • increased appetite
  • increased hair growth, especially on the face
  • increased in sexual ability, desire, drive, or performance
  • increased interest in sexual intercourse
  • sore gums
  • tenderness in the stomach area

For Healthcare Professionals

Applies to clonazepam: oral tablet, oral tablet disintegrating


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]


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

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]


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]


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]


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]


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]


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]


Common (1% to 10%): Allergic reaction
Rare (0.01% to 0.1%): Angioedema
Frequency not reported: Anaphylaxis[Ref]


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]


Common (1% to 10%): Appetite decreased
Frequency not reported: Anorexia, dehydration, gout, hunger abnormal, increased appetite, weight gain, weight loss[Ref]


Common (1% to 10%): Influenza
Frequency not reported: Infection mycotic, infection streptococcal, infection viral, moniliasis[Ref]


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]


Rare (0.01% to 0.1%): Decreased platelet count
Frequency not reported: Anemia, blood dyscrasias, eosinophilia, infectious mononucleosis, leukopenia, lymphadenopathy
Postmarketing reports: Thrombocytopenia[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]

Tachycardia occurred after IV administration.[Ref]


Frequency not reported: Abnormal liver function tests, hepatomegaly
Postmarketing reports: Transient elevations of serum transaminases and alkaline phosphatase[Ref]


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


Frequency not reported: Localized inflammation[Ref]


Frequency not reported: Cystitis[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Klonopin (clonazepam)." Roche Laboratories, Nutley, NJ.

Some side effects of Klonopin Wafer may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.