A patient presents with 2 weeks of diarrhoea after hiking and drinking stream water. Stool microscopy for ova and parasites is negative on 3 samples. NAAT for gastrointestinal pathogens is positive for Giardia lamblia. Appropriate treatment is:
- A Albendazole 400 mg daily for 5 days
- B Tinidazole 2 g stat single dose (preferred first-line) ✓
- C Metronidazole 400 mg three times daily for 5–7 days
- D Nitazoxanide 500 mg twice daily for 3 days
Correct answer: B. Tinidazole 2 g stat single dose (preferred first-line)
Explanation
Tinidazole 2 g as a single oral dose is the preferred treatment for Giardia infection with the highest cure rates (>90%) and superior compliance over multi-day regimens. Metronidazole 400–500 mg three times daily for 5–7 days is an effective alternative but requires longer duration. Albendazole 400 mg daily for 5 days is a secondary option with slightly lower efficacy. Nitazoxanide is used in metronidazole-refractory cases. NAAT of stool is more sensitive than conventional microscopy, particularly for detecting low parasite loads.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.