Levamisole

How it works

As an anthelmintic it acts as a nicotinic acetylcholine receptor agonist at the worm neuromuscular junction, causing spastic paralysis of the parasite; it also has poorly understood immunomodulatory effects in humans.

Prescribing in practice

• Agranulocytosis is a recognised serious adverse effect, so unexplained fever, sore throat or infection should prompt an urgent full blood count and review.
• Its use is limited and largely confined to specialist indications, and availability varies, so prescribing should follow current prescribing references and local guidance.
• It has been reported as an adulterant of illicit cocaine and can cause vasculitis and neutropenia in that context, which is relevant to differential diagnosis.

Monitoring

Monitor the full blood count, particularly the neutrophil count, and review for signs of infection during treatment.

Counselling the patient

• Seek urgent medical advice if you develop a fever, sore throat or mouth ulcers.
• Take the medicine exactly as directed for the prescribed course.
• Attend any blood tests requested while you are taking this medicine.

Evidence & guidelines

Use is based on established pharmacology and specialist guidance rather than a single landmark trial, and its profile is informed by post-marketing safety reports.