Letrax (Levamisole hydrochloride)

Letrax® (Levamisole Hydrochloride BP)

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Letrax® (Levamisole Hydrochloride BP)

Each tablet contains Levamisole Hydrochloride BP equivalent to Levamisole 40mg.

Levamisole hydrochloride is the active levo-isomer of tetramisole hydrochloride. Levamisole is active against intestinal nematode worms and appears to act by paralysing susceptible worms which are subsequently eliminated from the intestines. The drug is active against Ascaris lumbricoides (roundworms). Ancylostoma duodenale and Necator americanus (hookworms). Levamisole has also shown some activity against Enterobius vermicularis (pinworm, threadworm), Trichuris trichiura, Stangyloides stercoralis and Trichostrongylus colubrifomis.

Absorption and fate

Levamisole is rapidly absorbed from the gastrointestinal tract and eliminated from the plasma. It is metabolised in the liver and excreted via the urine and faeces. Following a single dose of 150mg by mouth in healthy adults, Levamisole is rapidly absorbed with mean peak plasma concentration of 0.7mcg (micrograms) per ml being achieved at 1.5 hours and rapidly eliminated, with plasma elimination half-life of 5-6 hours. The amount of unchanged drug excreted in the urine is inversely correlated with urinary pH. A mean of about 3% of an administered dose is excreted unchanged in the urine within 24 hours.



Levamisole is an anthelmintic agent indicated for the treatment of infections by the following gastro-intestinal worm species:

  • Ascaris lumbricoides
  • Necator americanus
  • Ancylostoma duodenale
  • Enterobius vermicularis
  • Trichuris trichiura
  • Strongyloides stercoralis
  • Trichostrongylus colubrifomis

Dosage and administration

Patient’s age in yearsWeight rangeNo. of Tablets
1-46kg to <16kg1
5-1516kg to <32kg2
16 and over32kg and above3

In case of severe hookworm infection, it is suggested that a second standard dose is given one or seven days after the first, whichever timing is feasible.


There are no absolute contraindications to the use of Levamisole


In case of concurrent microfinance, transient fever may occur


Although studies in animals have shown tat Levamisole produces no teratogenic effects current medical practice requires that the benefits of any drug used during pregnancy should be weighed against the possible dangers

Adverse reactions

Side effects are infrequent. They are usually mild and include nausea, vomiting, abdominal pain, giddiness and headache.

Treatment of overdose

Counter possible anticholinergic activity with e.g. Atropine. Control blood pressure and respiration. Do not give sedatives

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