What is Klonopin?
Klonopin (clonazepam) is in a group of drugs called benzodiazepines (ben-zoe-dye-AZE-eh-peens). Clonazepam affects chemicals in the brain that may become unbalanced and cause anxiety.
Klonopin is used to treat seizure disorders or panic disorder.
Klonopin may also be used for purposes not listed in this medication guide.
You should not use Klonopin if you have severe liver disease, of if you are allergic to clonazepam or to other benzodiazepines, such as alprazolam (Xanax), chlordiazepoxide (Librium), clorazepate (Tranxene), diazepam (Valium), lorazepam (Ativan), or oxazepam (Serax). Clonazepam may cause harm to an unborn baby, and may cause breathing or feeding problems in a newborn. But having seizures during pregnancy could harm both mother and baby. Do not start or stop taking this medicine during pregnancy without medical advice.
You may have thoughts about suicide while taking Klonopin. Your doctor will need to check you at regular visits. Do not miss any scheduled appointments. Call your doctor at once if you have any new or worsening symptoms such as: mood or behavior changes, depression, anxiety, or if you feel agitated, irritable, hostile, aggressive, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
Before you take Klonopin, tell your doctor if you have kidney or liver disease, glaucoma, any breathing problems, or a history of depression, suicidal thoughts, or addiction to drugs or alcohol.
Do not drink alcohol while taking Klonopin. This medication can increase the effects of alcohol. Clonazepam may be habit-forming and should be used only by the person it was prescribed for. Keep the medication in a secure place where others cannot get to it.
Before taking this medicine
You should not use Klonopin if you have severe liver disease or narrow-angle glaucoma, or if you are allergic to clonazepam or other benzodiazepines, such as alprazolam (Xanax), chlordiazepoxide (Librium), clorazepate (Tranxene), lorazepam (Ativan), or oxazepam (Serax).
To make sure you can safely take Klonopin, tell your doctor if you have any of these other conditions:
- kidney or liver disease;
- asthma, emphysema, bronchitis, chronic obstructive pulmonary disorder (COPD), or other breathing problems;
- a history of depression or suicidal thoughts or behavior; or
- a history of drug or alcohol addiction.
FDA pregnancy category D. Klonopin may cause harm to an unborn baby, and may cause breathing or feeding problems in a newborn. But having seizures during pregnancy could harm both mother and baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Do not start or stop taking clonazepam during pregnancy without medical advice. If you are pregnant, your name may be listed on a pregnancy registry. This is to track the outcome of the pregnancy and to evaluate any effects of clonazepam on the baby. Clonazepam may pass into breast milk and could harm a nursing baby. Do not breast-feed a baby while taking this medication.
See also: Pregnancy and breastfeeding warnings (in more detail)
The sedative effects of Klonopin may last longer in older adults. Accidental falls are common in elderly patients who take benzodiazepines. Use caution to avoid falling or accidental injury while you are taking this medicine. Clonazepam may be habit forming and should be used only by the person it was prescribed for. Never share this medicine with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it.
How should I take Klonopin?
Take Klonopin exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
Your doctor may occasionally change your dose to make sure you get the best results.
Swallow the regular tablet whole, with a full glass of water. Klonopin should be used for only a short time. Do not take this medication for longer than 9 weeks without your doctor’s advice.
To take the orally disintegrating tablet (wafer):
- Keep the tablet in its blister pack until you are ready to take it. Open the package and peel back the foil from the tablet blister. Do not push a tablet through the foil or you may damage the tablet.
- Using dry hands, remove the tablet and place it in your mouth. It will begin to dissolve right away.
- Do not swallow the tablet whole. Allow it to dissolve in your mouth without chewing.
- Swallow several times as the tablet dissolves. If desired, you may drink liquid to help swallow the dissolved tablet.
To be sure Klonopin is not causing harmful effects, your blood may need to be tested often. Your liver function may also need to be tested. Visit your doctor regularly.
Do not stop using Klonopin without first talking to your doctor, even if you feel fine. You may have increased seizures or unpleasant withdrawal symptoms if you stop using this medicine suddenly. Ask your doctor how to avoid withdrawal symptoms when you stop using this medicine.
You may need to use less and less before you stop the medication completely. Your doctor may also prescribe another seizure medication for you to start while you are stopping Klonopin.
Keep track of the amount of medicine used from each new bottle. Klonopin is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of Klonopin can be fatal.
Overdose symptoms may include extreme drowsiness, confusion, muscle weakness, and fainting.
What should I avoid?
Drinking alcohol can increase certain side effects of Klonopin. This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Klonopin side effects
Get emergency medical help if you have any of these signs of an allergic reaction to Klonopin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, depression, anxiety, or if you feel agitated, irritable, hostile, aggressive, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have a serious side effect while taking Klonopin such as:
- confusion, hallucinations, unusual thoughts or behavior;
- unusual risk-taking behavior, no fear of danger;
- weak or shallow breathing;
- unusual or involuntary eye movements;
- pounding heartbeats or fluttering in your chest;
- painful or difficult urination, urinating less than usual;
- pale skin, easy bruising or bleeding; or
- new or worsening seizures.
Less serious Klonopin side effects may include:
- drowsiness, dizziness, problems with thinking or memory;
- tired feeling, muscle weakness, loss of balance or coordination;
- slurred speech, drooling or dry mouth, sore gums;
- runny or stuffy nose;
- loss of appetite, nausea, diarrhea, constipation;
- blurred vision;
- sleep problems (insomnia);
- skin rash; or
- weight changes.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Klonopin?
Cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for depression or anxiety can add to sleepiness caused by Klonopin. Tell your doctor if you regularly use any of these medicines, or any other seizure medications or benzodiazepines.
Also tell your doctor if you are using any of the following drugs:
- propantheline (Pro-Banthine);
- an antibiotic such as clarithromycin (Biaxin), dalfopristin/quinupristin (Synercid), erythromycin (E.E.S., EryPed, Ery-Tab, Erythrocin, Pediazole), or telithromycin (Ketek);
- an antifungal medicine such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), or voriconazole (Vfend);
- an antidepressant such as amitriptyline (Elavil, Vanatrip, Limbitrol), doxepin (Sinequan), nefazodone, nortriptyline (Pamelor), and others;
- a barbiturate such as butabarbital (Butisol), secobarbital (Seconal), pentobarbital (Nembutal), or phenobarbital (Solfoton);
- an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate); or
- medicines to treat psychiatric disorders, such as chlorpromazine (Thorazine), droperidol (Inapsine), haloperidol (Haldol), mesoridazine (Serentil), pimozide (Orap), thioridazine (Mellaril), or thiothixene (Navane).
This list is not complete and other drugs may interact with Klonopin. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.
For the Consumer
Applies to clonazepam: oral solution, oral tablet, oral tablet disintegrating
In addition to its needed effects, some unwanted effects may be caused by clonazepam (the active ingredient contained in Klonopin). In the event that any of these side effects do occur, they may require medical attention.
You should check with your doctor immediately if any of these side effects occur when taking clonazepam:
- Body aches or pain
- difficulty with breathing
- ear congestion
- feeling sad or empty
- 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
- sore throat
- trouble with concentrating
- trouble with sleeping
- unsteadiness, trembling, or other problems with muscle control or coordination
- unusual tiredness or weakness
- Being forgetful
- bladder pain
- bloody or cloudy urine
- changes in patterns and rhythms of speech
- 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
- problems in urination or increase in the amount of urine
- slurred speech
- sore throat
- trouble with speaking
- Burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
- changes in skin color
- chest pain or discomfort
- cold sweats
- cough or hoarseness
- difficulty with sleeping
- dizziness, faintness, or lightheadedness when getting up from a lying or sitting position
- excessive dreaming
- excessive muscle tone
- 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
- 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
- sense of detachment from self or body
- shakiness in the legs, arms, hands, or feet
- shortness of breath
- 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
- troubled breathing
- unable to sleep
- vision changes
Incidence not known
- black, tarry stools
- bleeding gums
- blood in the urine or stools
- change in consciousness
- chest congestion
- difficulty with coordination
- double vision
- 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
- irregular, fast, slow, or shallow breathing
- irregular, twisting uncontrolled movement of the face, hands, arms, or legs
- loss of consciousness
- 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
- right upper abdominal pain and fullness
- 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 weak feeling
- vivid dreams
- weight loss or gain
Some of the side effects that can occur with clonazepam may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:
- Decreased interest in sexual intercourse
- difficulty with swallowing
- dryness or soreness of the throat
- heavy bleeding
- 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
- bleeding after defecation
- blistering, burning, crusting, dryness, or flaking of the skin
- blurred or loss of vision
- decrease or change in vision
- difficulty with moving
- disturbed color perception
- double vision
- dryness of the eyes
- 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
- increased watering of the mouth
- irregularities in menstruation
- itching in 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
- 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
- skin rash cracks in the skin at the corners of the mouth
- 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
- tooth disorder
- 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 were drowsiness, ataxia, and behavioral problems.[Ref]
Common (1% to 10%): Depression, emotional lability, confusion
Frequency not reported: Hallucinations, hysteria, insomnia, psychosis, excitability, irritability, aggressive behavior, agitation, hostility, anxiety, vivid dreams, hyperactivity, hypoesthesia, organic disinhibition, depersonalization, apathy, excitement, feeling mad, illusion, nightmares, sleep disorders, suicide ideation[Ref]
Very common (10% or more): Somnolence (up to 50%), Dizziness (up to 12%)
Common (1% to 10%): Nervousness, ataxia, reduced intellectual ability, abnormal coordination, dysarthria, memory disturbance
Frequency not reported: Aphonia, choreiform movements, coma, dysdiadochokinesis, “glassy-eyed” appearance, headache, hemiparesis, hypotonia, nystagmus, slurred speech, tremor, vertigo, taste loss, migraine, paresthesia[Ref]
Common (1% to 10%): Allergic Reaction[Ref]
Frequency not reported: Hepatomegaly, transient elevations of serum transaminases and alkaline phosphatase[Ref]
Common (1% to 10%): Fatigue
Frequency not reported: Ankle edema, facial edema, periorbital edema, general deterioration, fever, wound, shivering, malaise, pain, localized inflammation, earache, motion sickness[Ref]
Common (1% to 10%): Decreased libido, increased libido, urinary tract infection, dysmenorrhea, colpitis, impotence, delayed ejaculation
Frequency not reported: Dysuria, enuresis, nocturia, urinary retention, breast pain, menstrual irregularity, dysuria, cystitis, polyuria, urinary incontinence, bladder dysfunction, urinary tract bleeding, urine discoloration[Ref]
Frequency not reported: Lymphadenopathy, anemia, leukopenia, thrombocytopenia, eosinophilia, dermal bleeding[Ref]
Common (1% to 10%): Constipation, decreased appetite, abdominal pain
Frequency not reported: Coated tongue, diarrhea, dry mouth, encopresis, gastritis, increased appetite, nausea, sore gum, abdominal discomfort, gastrointestinal inflammation, stomach upset, toothache, flatulence, pyrosis, increased saliva, tooth disorder, frequent bowel movements, pelvic pain, dyspepsia, hemorrhoids, hypersalivation[Ref]
Very common (10% or more): Upper respiratory tract infection (10%)
Common (1% to 10%): Sinusitis, rhinitis, coughing, pharyngitis, bronchitis, influenza
Frequency not reported: Respiratory depression, chest congestion, rhinorrhea, hypersecretion in upper respiratory passages, excessive sneezing, asthmatic attack, dyspnea, nosebleed, pneumonia, pleurisy[Ref]
Frequency not reported: Hair loss, hirsutism, skin rash, cellulitis, acne flare, alopecia, xeroderma, contact dermatitis, pruritus, pustular reaction, skin burns, skin disorder[Ref]
Common (1% to 10%): Blurred vision
Frequency not reported: Diplopia, eye irritation, visual disturbance, eye twitching, styes, visual field defect, xerophthalmia[Ref]
Frequency not reported: Anorexia, dehydration, weight loss/gain, thirst, gout[Ref]
Frequency not reported: Palpitations, chest pain, postural hypotension, heart rate and rhythm disorders, flushing, leg thrombophlebitis[Ref]
Frequency not reported: Reversible development of premature secondary sex
characteristics in children (incomplete precocious puberty)[Ref]
Frequency not reported: Mycotic infection, viral infection, streptococcal infection, herpes simplex infection, infectious mononucleosis, moniliasis[Ref]
Common (1% to 10%): Myalgia
Frequency not reported: Muscle weakness, back pain, traumatic fracture, sprains/ strains, leg pain, neck pain, muscle cramps, leg cramps, ankle pain, shoulder pain, tendinitis, arthralgia, hypertonia, lumbago, feet pain, jaw pain, knee pain, knee swelling[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.