Drugs for Giardiasis

DRUGS FOR GIARDIASIS

Giardia lamblia is a flagellate protozoon which mostly lives as a commensal in the intestine. It sometimes invades the mucosa and causes diarrhoea requiring treatment. Many drugs useful in amoebiasis are also effective in giardiasis.

Metronidazole 200 mg TDS (children 15 mg/ kg/day) for 7 days or 2 g daily for 3 days or tinidazole 0.6 g daily for 7 days or 2 g single dose or secnidazole 2 g single dose may be considered as the drugs of choice.

Nitazoxanide This prodrug of the PFOR enzyme inhibitor tizoxanide has recently become available for the treatment of diarrhoea and dysentery caused by Giardia lamblia, E. histolytica, C. parvum. The dosage schedule is convenient—500 mg (children 7.5 mg/kg) twice daily for 3 days, efficacy high (80–90%) and tolerability good.

Quiniodochlor 250 mg TDS for 7 days is a somewhat less effective alternative.

Furazolidone It is a nitrofuran compound active against many gram-negative bacilli including Salmonella and Shigella, also Giardia and Trichomonas.

For giardiasis 100 mg TDS for 5–7 days is inferior to metronidazole or tinidazole. It has also been used in bacterial enteritis, food poisoning diarrhoeas and bacillary dysentery, but is not a first line treatment for any of these.

Furazolidone is partly absorbed from intestines and excreted in urine which turns orange— patients should be told about it. Side effects are mild and infrequent—nausea, headache, dizziness.

FUROXONE 100 mg tab, 25 mg/5 ml susp.