BMA Concise Guide to Medicine & Drugs

Clonazepam

Brand name Rivotril

Used in the following combined preparations None

QUICK REFERENCE

Drug group Benzodiazepine anticonvulsant drug

Overdose danger rating Medium

Dependence rating Medium

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Clonazepam belongs to a group of drugs known as the benzodiazepines, which are mainly used in the treatment of anxiety and insomnia (see Anti-anxiety drugs). However, clonazepam is usually used as an anticonvulsant to prevent and treat epileptic seizures. It is particularly useful for the prevention of brief muscle spasms (myoclonus) and absence seizures (petit mal) in children but other forms of epilepsy, such as sudden flaccidity or seizures induced by flashing lights, also respond to clonazepam treatment. Being a benzodiazepine, the drug also has sedative effects.

Clonazepam is used either alone or together with other anticonvulsant drugs. Its anticonvulsant effect may begin to wear off after some months, which often limits its long-term use.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, injection.

Frequency and timing of doses 1–4 x daily.

Dosage range Adults 1mg daily at night (starting dose), increased gradually to 4–8mg daily (maintenance dose). Children Reduced dose according to age and weight.

Onset of effect 1–4 hours.

Duration of action 24–48 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose No cause for concern, but take as soon as you remember. Take your next dose when it is due.

Stopping the drug Do not stop taking the drug without consulting your doctor because symptoms may recur, and withdrawal symptoms may occur.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Larger overdoses may cause excessive drowsiness and confusion. Notify your doctor.

POSSIBLE ADVERSE EFFECTS

The principal adverse effects of clonazepam are related to its sedative and tranquillizing properties. They include daytime drowsiness, dizziness, unsteadiness, altered behaviour, forgetfulness, confusion, and muscle weakness. These effects normally diminish after the first few days of treatment and can often be reduced by medically supervised adjustment of the dosage.

INTERACTIONS

Sedatives All drugs that have a sedative effect on the central nervous system are likely to increase the sedative properties of clonazepam. Such drugs include anti-anxiety and sleeping drugs, antihistamines, opioid analgesics, antidepressants, and antipsychotics.

Other anticonvulsants Clonazepam may alter the effects of other anticonvulsants you are taking, or they may alter its effect. Adjustment of dosage or change of drug may be necessary.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have severe respiratory disease.

· You have long-term liver or kidney problems.

· You have porphyria.

· You have myasthenia gravis.

· You have had problems with drug or alcohol abuse.

· You are taking other medicines.

Pregnancy May cause adverse effects in the baby if used in late pregnancy or labour. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby adversely. Discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 Reduced dose may be necessary.

Driving and hazardous work Your underlying condition, as well as the possibility of drowsiness while taking clonazepam, may make such activities inadvisable. Discuss with your doctor.

Alcohol Avoid. Alcohol may increase the sedative effects of this drug.

PROLONGED USE

Both beneficial and adverse effects of clonazepam may become less marked during prolonged treatment as the body adapts. Prolonged use may also result in dependence and difficulty in withdrawing.