BMA Concise Guide to Medicine & Drugs

Orphenadrine

Brand names Biorphen, Disipal

Used in the following combined preparations None

QUICK REFERENCE

Drug group Drug for parkinsonism

Overdose danger rating High

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Orphenadrine is an anticholinergic drug that is prescribed to treat all forms of Parkinson’s disease. However, it is less effective against the idiopathic form of the disease than other drugs (such as levodopa) and can cause confusion. Orphenadrine is particularly valuable for relieving the tremor and muscle rigidity that often occur with Parkinson’s disease; it is less helpful for improving the slowing of movement that also commonly affects sufferers. It also helps reduce the excessive salivation or dribbling that can occur with Parkinson’s disease and is widely used to treat the parkinson-like side effects of antipsychotic drugs. The effects of orphenadrine may become less noticeable after it has been taken for a long time.

Orphenadrine also possesses muscle-relaxant properties and is occasionally used to treat muscle pain and restless leg syndrome.

INFORMATION FOR USERS

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

How taken/used Tablets, liquid.

Frequency and timing of doses 2–3 x daily.

Adult dosage range 150–400mg daily.

Onset of effect Within 60 minutes.

Duration of action 8–12 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children. Protect 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 the drug without consulting your doctor; symptoms may recur.

OVERDOSE ACTION

Seek immediate medical advice in all cases. Take emergency action if palpitations, seizures, or loss of consciousness occur.

POSSIBLE ADVERSE EFFECTS

The adverse effects of orphenadrine are similar to those of other anticholinergic drugs, and the more common effects often diminish with a reduction in dosage. Common side effects include dry mouth and skin, difficulty in passing urine, constipation, dizziness, and blurred vision. Discuss with your doctor if blurred vision occurs or if the other symptoms are severe. Rarely, confusion or agitation may occur; if so, discuss with your doctor. If you experience palpitations, you should stop taking the drug and contact your doctor immediately.

INTERACTIONS

General note Orphenadrine reduces gastric motility (spontaneous stomach movements that move stomach contents into the intestine) and so may affect the absorption of other oral drugs.

Anticholinergic drugs (e.g. tiotropium, chlorphenamine, oxybutynin) The anticholinergic effects of orphenadrine are likely to be increased by these drugs.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have heart problems.

· You have had glaucoma.

· You have difficulty in passing urine and have an enlarged prostate.

· You are taking other medicines.

Pregnancy Safety not established. Discuss with your doctor.

Breast-feeding Safety not established. Discuss with your doctor.

Infants and children Not usually prescribed.

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 orphenadrine affects you because the drug can cause dizziness, lightheadedness, and blurred vision.

Alcohol Avoid. Alcohol can worsen some of the adverse effects of orphenadrine.

PROLONGED USE

No problems expected. Effectiveness in treating Parkinson’s disease may diminish with time.