Highly Protein Bound Drugs
Moderate
Database
Plasma protein-binding competition
Monitor for narrow-index drug toxicity
Source: Kimi deep-research + Cla
Drug reference
Nitazoxanide
Thiazolide antiparasitic/antiprotozoal · Antidiarrheal
Also known as Tizoxanide, Alinia
START
500 mg PO BID with food ×3 days (paediatric weight/age-based)
TYPICAL MAX
1 g/day (500 mg BID)
STOP IF
Hypersensitivity reaction
WATCH
Hydration in diarrhoeal illness; counsel benign urine discoloration; take with food
CDSCO approvedSchedule HATC P01AX11
KDIGO 2024 + manufacturer label
- ONSET
- 2h · absorption (with food)
- PEAK
- 3h · tizoxanide Cmax
- t½
- 2h · tizoxanide t½
- DURATION
- 12h · BID interval
EXCRETION
Hydrolysis to tizoxanide; renal/biliary/faecal
route + CYP
INTERACTIONS
—
none in our sources
PREGNANCY
Use only if clearly needed — limited human data (animal studies reassuring)
FDA category + note
Available in India
31 branded formulations. Look up specific brands in the Drugs workspace.
Mechanism
Active metabolite tizoxanide inhibits the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme-dependent electron-transfer essential for anaerobic energy metabolism of protozoa, helminths and anaerobic bacteria; also antiviral activity in some settings.
Indications
Cryptosporidium parvum diarrhoea (immunocompetent)Giardia lamblia infection(Off-label) other intestinal protozoa/helminths; viral gastroenteritis (variable evidence)
Dosing
- Adult
- 500 mg PO twice daily with food for 3 days.
- Pediatric
- 1–3 years 100 mg q12h; 4–11 years 200 mg q12h; ≥12 years 500 mg q12h ×3 days (with food).
- Renal adjustment
- No data — caution in renal impairment.
- Hepatic adjustment
- No data — caution in hepatic impairment.
- Geriatric
- Limited data; usual dosing with caution.
- Max dose
- 1 g/day (500 mg BID)
Pharmacokinetics
Onset
Symptom improvement over the 3-day course
Peak effect
Tizoxanide Cmax ~1–4 h (food increases absorption)
Duration
3-day course
Half-life
Tizoxanide ~1.5–2.5 h
Bioavailability
Increased ~2-fold with food
Protein binding
>99% (tizoxanide)
Metabolism
Rapid hydrolysis to active tizoxanide → glucuronide
Excretion
Renal, biliary and faecal
Contraindications
- Hypersensitivity to nitazoxanide
Side effects
Common
Abdominal painDiarrhoeaNausea/vomitingHeadacheChromaturia (yellow-green urine — benign)
Serious
- Hypersensitivity reactions (rare)
- No major serious toxicity established at recommended doses
Pregnancy & lactation
Pregnancy
Use only if clearly needed — limited human data (animal studies reassuring)
Lactation
Limited data; short course — caution
Drug interactions
Phenytoin
Moderate
Database
Increased plasma levels of phenytoin.
Source: DDInter
Warfarin
Moderate
Database
Highly protein-bound tizoxanide may displace warfarin → raised INR
Monitor INR with concurrent use
Source: Kimi deep-research + Cla
9 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.
Related guidelines
Ask House about Nitazoxanide
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Harrison 22e, Katzung·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19