BMA Concise Guide to Medicine & Drugs


Brand names [diazepam] Dialar, Diazemuls, Diazepam Rectubes, Rimapam, Stesolid, Tensium, Valclair; [lorazepam] Ativan

Used in the following combined preparations None


Drug group Benzodiazepine anti-anxiety drug, muscle relaxant, and anticonvulsant

Overdose danger rating Medium

Dependence rating High

Prescription needed Yes

Available as generic Yes


Introduced in the early 1960s, diazepam is the best known and most widely used benzodiazepine, and lorazepam is closely related to it. Benzodiazepines help to relieve tension and nervousness, relax muscles, and encourage sleep. Their actions and adverse effects are described in anti-anxiety drugs.

Diazepam and lorazepam have a wide range of uses. Besides being commonly used in the treatment of anxiety and anxiety-related insomnia, they are given in the treatment of alcohol withdrawal, and for the relief of epileptic seizures. Diazepam is also given as a muscle relaxant. Given intravenously, they are used to sedate people undergoing certain uncomfortable medical procedures.

Diazepam and lorazepam can be habit-forming if taken regularly over a long period. Their effects may also diminish with time. For these reasons, courses of treatment are limited to two weeks whenever possible.


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

How taken/used Tablets, liquid, injection, suppositories, rectal solution.

Frequency and timing of doses 1–4 x daily.

Dosage range Anxiety 2–30mg daily (diazepam); 1–4mg daily (lorazepam).

Onset of effect Immediate effect (injection); 30 minutes–2 hours (other methods of administration).

Duration of action Up to 24 hours; some effect: up to 4 days.

Diet advice None.

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

Missed dose Take as soon as you remember. If your next dose is due within 2 hours, take a single dose now and skip the next.

Stopping the drug If you have been taking the drug continuously for less than 2 weeks, it can be safely stopped as soon as you no longer need it. However, if you have been taking it for longer, consult your doctor, who will supervise a gradual reduction in dosage. Stopping abruptly may lead to withdrawal symptoms.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Larger overdoses may cause excessive drowsiness and could cause deep coma. Notify your doctor in all cases.


The principal adverse effects of these drugs are related to their sedative properties. They include daytime drowsiness, dizziness, unsteadiness, forgetfulness, and confusion. More rarely, the drugs may also cause headache and blurred vision. These effects normally diminish after a few days and can often be reduced by adjusting the dosage. If they are severe or persistent, consult your doctor.


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

Omeprazole (diazepam), cimetidine, isoniazid, fosamprenavir, and ritonavir These drugs may increase blood levels of diazepam and lorazepam and the risk of adverse effects.

Rifampicin may reduce the effects of diazepam.


Be sure to tell your doctor if:

· You have severe respiratory disease.

· You have long-term liver or kidney problems.

· You have had problems with alcohol or drug abuse.

· You have myasthenia gravis or muscle weakness.

· You suffer from sleep apnoea.

· You have a marked personality disorder.

· You have porphyria.

· You are taking other medicines.

Pregnancy Not usually recommended; may cause adverse effects on newborn baby at the time of delivery. Discuss with your doctor.

Breast-feeding The drugs pass into the breast milk and may affect the baby. Discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 Increased likelihood of adverse effects. Reduced dose may therefore be necessary.

Driving and hazardous work Avoid such activities until you have learned how diazepam and lorazepam affect you because the drugs can cause reduced alertness, slowed reactions, and increased aggression.

Alcohol Avoid. Alcohol may increase the sedative effects of these drugs.


Regular use of these drugs over several weeks can lead to a reduction in their effect as the body adapts. They may also be habit-forming when taken for extended periods, and severe withdrawal reactions can occur if they are stopped abruptly.