Indications
Orphenadrine Hydrochloride is an anticholinergic medicine. It is mainly used to treat movement problems caused by Parkinson’s disease (parkinsonism) and stiffness, tremor and abnormal movements caused by some antipsychotic medicines (drug-induced extrapyramidal symptoms). It may also be used to relieve painful muscle spasm.
How It Works
In Parkinson’s disease and drug-induced movement problems, the brain has too little dopamine action compared with acetylcholine, another nerve chemical. Orphenadrine blocks acetylcholine, helping to restore the balance and reduce stiffness, tremor and excess saliva. It also has a muscle-relaxing effect.
Dosage and Administration
Take as prescribed. The doctor usually starts with a low dose divided through the day and increases it slowly, every few days, until symptoms are controlled. Do not change the dose or stop suddenly on your own, as symptoms may return or worsen. Not recommended for children.
Interactions
- Other anticholinergic medicines (e.g. Trihexyphenidyl, Amitriptyline, Chlorpromazine, some antihistamines, bladder medicines): dry mouth, constipation, confusion and urine retention may increase.
- Alcohol and medicines that cause drowsiness: more drowsiness.
- Levodopa: its absorption may be reduced.
- Propoxyphene: confusion, anxiety and tremor have been reported.
Contraindications
Do not use if you have glaucoma (raised eye pressure), an enlarged prostate or difficulty passing urine, blockage of the stomach or bowel, myasthenia gravis, tardive dyskinesia (late-onset abnormal movements from antipsychotics), porphyria, or allergy to Orphenadrine.
Side Effects
Common side effects are dry mouth, blurred vision, drowsiness, dizziness, nausea, constipation, difficulty passing urine and fast heartbeat. Older people may get confusion, memory problems, restlessness or hallucinations. With high doses, excitement and sleeplessness may occur.
Get urgent medical help if you cannot pass urine, have severe eye pain with blurred vision, a very fast or irregular heartbeat, severe confusion or hallucinations, or signs of an allergic reaction.
Pregnancy and Lactation
Safety in pregnancy and breastfeeding is not well established. Use only if your doctor considers it necessary.
Precautions and Warnings
- Use with caution in older people and in those with heart disease, fast heart rate, high blood pressure, or kidney or liver problems.
- It may cause drowsiness and blurred vision; do not drive if affected.
- It reduces sweating, so avoid overheating in hot weather.
- Some people misuse it for its mood effects; take only as prescribed.
Overdose
Overdose may cause dilated pupils, hot dry flushed skin, fever, fast or irregular heartbeat, agitation, confusion, hallucinations, fits and coma. It can be life-threatening. Get emergency help straight away.
Therapeutic Class
Anticholinergic antiparkinsonian agent.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.