Flexiril

Indications

Baclofen is used to relieve muscle stiffness and spasms (spasticity) caused by conditions such as multiple sclerosis, spinal cord injury or disease, cerebral palsy and stroke.

How It Works

Baclofen acts on the spinal cord to calm the nerve signals that make muscles tighten. This relaxes stiff muscles and reduces painful spasms, making movement and care easier.

Dosage and Administration

• Adults: usually started at 5 mg three times a day and increased slowly, about every 3 days, as the doctor directs. The usual maintenance dose is up to 60 mg a day in divided doses; higher doses are only used under specialist care.
• Children: as prescribed, based on age and weight.
• Injection into the spinal fluid (intrathecal): given only by specialists in hospital.

Take with food or milk if it upsets the stomach. Do not stop suddenly; the dose must be lowered gradually over 1 to 2 weeks or as the doctor advises.

Interactions

Alcohol, sleeping tablets, Diazepam and other sedatives, opioid painkillers, antihistamines that cause drowsiness and some antidepressants such as Amitriptyline can increase drowsiness and slow breathing. Medicines for high blood pressure may lower blood pressure too much. Baclofen may increase confusion or hallucinations with Levodopa.

Contraindications

Allergy to Baclofen. Use only with medical advice in people with an active stomach ulcer.

Side Effects

Common, especially at the start: drowsiness, dizziness, tiredness, muscle weakness, nausea, confusion and low blood pressure. Others include headache, sleep problems, constipation and needing to pass urine often.

Get urgent medical help if you have very slow or shallow breathing, extreme drowsiness, fits, severe confusion or hallucinations, or, after missing doses or stopping, a high temperature, worsening spasms, agitation or a fast heartbeat.

Pregnancy and Lactation

Use in pregnancy only if the doctor decides the benefit outweighs the risk; babies may have withdrawal symptoms after birth if it was taken late in pregnancy. Small amounts pass into breast milk; ask the doctor before breastfeeding.

Precautions and Warnings

Use with care in kidney disease (a lower dose is usually needed), epilepsy, mental health conditions, after a stroke, in older people and in breathing or liver problems. It can make you drowsy, so do not drive or use machines until you know how it affects you, and avoid alcohol. Never stop taking it suddenly.

Overdose

Overdose can cause severe drowsiness, muscle floppiness, slow breathing, fits and coma. This is an emergency; get medical help at once.

Therapeutic Class

Centrally acting skeletal muscle relaxant.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.