BMA Concise Guide to Medicine & Drugs

Baclofen

Brand names Lioresal, Lyflex

Used in the following combined preparations None

QUICK REFERENCE

Drug group Muscle relaxant drug

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Baclofen is a muscle-relaxant drug that acts on the central nervous system, including the spinal cord. The drug relieves the spasms, cramping, and muscle rigidity (commonly known as spasticity) caused by a variety of disorders, including multiple sclerosis, spinal cord injury, brain injury, cerebral palsy, or stroke. Although this drug does not cure any of these disorders, it increases mobility, allowing other treatment, such as physiotherapy, to be carried out.

Baclofen is less likely to cause muscle weakness than similar drugs, and its side effects, such as dizziness or drowsiness, are usually temporary. Elderly people are more susceptible to side effects, especially during early stages of treatment.

INFORMATION FOR USERS

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

How taken/used Tablets, liquid, injection (specialist use).

Frequency and timing of doses 3 x daily with food or milk.

Adult dosage range 15mg daily (starting dose). Daily dose may be increased by 15mg every 3 days as necessary. Maximum daily dose: 100mg.

Onset of effect Some benefits may appear after 1–3 hours, but full beneficial effects may not be felt for several weeks. A dose 1 hour before a specific task will improve mobility.

Duration of action Up to 8 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children. Protect liquid from light.

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 Do not stop taking the drug without consulting your doctor who will supervise a gradual reduction in dosage. Abrupt cessation may cause hallucinations, confusion, anxiety, seizures, and worsening spasticity.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Large overdoses may cause weakness, vomiting, and severe drowsiness. Notify your doctor.

POSSIBLE ADVERSE EFFECTS

The common adverse effects, such as dizziness and drowsiness, are related to the sedative effects of the drug. Such effects may be minimized by starting with a low dose and gradually increasing it. Nausea and muscle weakness may also occur. Rarer adverse effects include constipation or diarrhoea, headache, and difficulty in passing urine. If any of the adverse effects are severe, or if blurred vision or confusion occur, you should consult your doctor.

INTERACTIONS

Antihypertensive and diuretic drugs Baclofen may increase the blood-pressure-lowering effect of such drugs.

Drugs for parkinsonism Some drugs used for parkinsonism may cause confusion and hallucinations if taken with baclofen.

Sedatives All drugs with a sedative effect on the central nervous system may increase the sedative properties of baclofen.

Tricyclic antidepressants may increase the effects of baclofen, leading to muscle weakness.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have difficulty in passing urine.

· You have had a peptic ulcer.

· You have had epileptic seizures or a stroke.

· You have diabetes.

· You are being treated for high blood pressure.

· You have porphyria.

· You have Parkinson’s disease.

· You suffer with breathing problems.

· You are taking other medicines.

Pregnancy Safety in pregnancy not established. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk, but at normal doses adverse effects are unlikely. Discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 Increased likelihood of adverse effects at start of treatment. Reduced initial dose may therefore be necessary.

Driving and hazardous work Avoid such activities until you have learned how baclofen affects you because the drug can cause drowsiness, decreased alertness, and blurred vision.

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

Surgery and general anaesthetics Be sure to inform your doctor or dentist that you are taking baclofen before you have a general anaesthetic.

PROLONGED USE

No problems expected.