Clonazepam

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Photo by: Nikolai Sorokin

Definition

Clonazepam belongs to a group of drugs called benzodiazepines. Benzodiazepines are medications that help relieve nervousness, tension, symptoms of anxiety, and some types of seizures by slowing the central nervous system. In the United States, clonazepam is sold under brand name Klonopin.

Purpose

Although clonazepam is approved by the United States Food and Drug Administration (FDA) for the treatment of panic disorder and some types of epilepsy, it is also used to treat social phobia , mania, and post-traumatic stress disorder .

Description

Clonazepam belongs to a group of drugs called benzodiazepines. Benzodiazepines are sedative-hypnotic drugs that help to relieve nervousness, tension, anxiety symptoms, and seizures by slowing the central nervous system. To do this, they block the effects of a specific chemical involved in the transmission of nerve impulses in the brain , decreasing the excitement level of the nerve cells.

When clonazepam is used to treat panic disorder, it is more sedating than alprazolam , another benzodiazepine drug used to treat panic disorder. However, unlike alprazolam, clonazepam may trigger depressive episodes in patients with a previous history of depression. In people who experience social phobia, treatment with clonazepam reduces the rate of depression. The use of clonazepam for social phobia is considered off-label use—a use that is legal, but not specifically approved by the FDA.

Clonazepam comes in 0.5 mg-, 1 mg-, and 2 mg tablets.

Recommended dosage

For panic disorder, the initial recommended dose is 0.25 mg twice daily. This dose can be increased every three days in increments of 0.125–0.25 mg twice daily. The target dose for panic disorder is 1.0 mg per day, although some people benefit from doses up to a maximum of 4 mg per day. When a person stops taking clonazepam, the drug should be gradually discontinued by decreasing the dose by 0.125 mg twice daily every three days.

Although clonazepam is not FDA-approved for the treatment of post-traumatic stress disorder, doses in the range of 0.25–3 mg daily appears to help treat symptoms of this disorder. Daily dosages for the treatment of social phobia range from 1.0–2.5 mg, while the dosage to control mania may be as high as 10 mg daily.

Precautions

Women who are pregnant should not use clonazepam, because it may harm the developing fetus. Clonazepam should never be taken by people who have had an allergic reaction to it or another benzodiazepine drug such as diazepam (Valium). People with narrow-angle glaucoma or severe liver disease should not take clonazepam. People who have kidney disease may need to take a reduced dosage of the drug. Saliva production may increase while taking clonazepam. Because of this, people with respiratory disease or an impaired gag reflex should use clonazepam with close physician supervision.

Because clonazepam is a nervous system depressant, it should not be taken with other such depressants, such as alcohol, other sedatives, sleeping pills, or tranquilizers. People taking clonazepam may feel unusually drowsy and mentally sluggish when they first start taking the drug. They should not drive, operate dangerous machinery, or engage in hazardous activities that require mental alertness until they see how clonazepam affects them. This excessive sedation usually goes away after a short time on the drug.

People who have underlying depression should be closely monitored while taking clonazepam, especially if they are at risk for attempting suicide .

Side effects

The main side effects of clonazepam are sedation, dizziness, impaired coordination, depression, and fatigue . Some people experience decreased sex drive while taking clonazepam.

A small number of people develop sinus problems and upper respiratory tract infections while taking clonazepam. One of the side effects of clonazepam may be increased salivation. This may cause some people to start coughing while taking clonazepam. Clonazepam may also cause anorexia and dry mouth. It may cause either constipation or diarrhea. There are a few reports of clonazepam causing menstrual irregularities or blurred vision.

Interactions

Clonazepam may increase the sedative effects of other drugs that depress the central nervous system such as certain pain strong medicines (opiates such as codeine, oxycodone, hydromorphone) and antihistamines (found in many cold and allergy medications). The sedative effect is also increased if clonazepam is taken with alcohol.

Disulfiram (Antabuse), a medication used to treat alcohol dependence, increases the effect of clonazepam. Medications that make clonazepam ineffective include phenobarbital, phenytoin, carbamazepine , theophylline, rifampin, and rifabutin.

Resources

BOOKS

Kaplan, Harold. Comprehensive Textbook of Psychiatry. Williams and Wilkins, 1995.

Lacy, Charles F. Drug Information Handbook. Lexi-Comp, Inc. 2002.

PERIODICALS

Valenca, Alexandre. "Smoking and Panic Disorder." Psychiatric Service 52, no. 8 (2001):1105-06.

Ajna Hamidovic, Pharm.D.