# Giardiasis - Category: infectious - Review status: reviewed (every claim checked against a document named on this page) - Sources: ALINIA (nitazoxanide) US prescribing information, section 2.1 Recommended Dosage, Table 1 (DailyMed SetID e90f98d9-3c9b-4e75-ba18-5517283eadf0) · WHO Parasitic Diseases 2021 · Egyptian National Drug Formulary - Antimicrobial 2023 (metronidazole monograph) · Tindamax (tinidazole) US prescribing information, Dosage and Administration - Giardiasis (DailyMed, Mission Pharmacal) - Verified date: 2026-08 ## Verified against - Egyptian National Drug Formulary - Antimicrobial 2023 (metronidazole monograph) - Tindamax (tinidazole) US prescribing information, Dosage and Administration - Giardiasis (DailyMed, Mission Pharmacal) - ALINIA (nitazoxanide) US prescribing information, section 2.1 Recommended Dosage, Table 1 (DailyMed SetID e90f98d9-3c9b-4e75-ba18-5517283eadf0) - Giardiasis - disease-level clinical article (giardiasis-clinical.txt) ## Treatment metadata - Metronidazole — 250 mg — oral.solid - Tinidazole — 500 mg — oral.solid - Nitazoxanide — 500 mg — oral.solid ## Complete treatment card ```text GIARDIASIS Sources: ALINIA (nitazoxanide) US prescribing information, section 2.1 Recommended Dosage, Table 1 (DailyMed SetID e90f98d9-3c9b-4e75-ba18-5517283eadf0) · WHO Parasitic Diseases 2021 · Egyptian National Drug Formulary - Antimicrobial 2023 (metronidazole monograph) · Tindamax (tinidazole) US prescribing information, Dosage and Administration - Giardiasis (DailyMed, Mission Pharmacal) Review status: REVIEWED against Egyptian National Drug Formulary - Antimicrobial 2023 (metronidazole monograph), Tindamax (tinidazole) US prescribing information, Dosage and Administration - Giardiasis (DailyMed, Mission Pharmacal), ALINIA (nitazoxanide) US prescribing information, section 2.1 Recommended Dosage, Table 1 (DailyMed SetID e90f98d9-3c9b-4e75-ba18-5517283eadf0), Giardiasis - disease-level clinical article (giardiasis-clinical.txt) (2026-08) IS IT THIS? - reference only, to read alongside your own examination SYMPTOMS - what the patient reports (12) - Diarrhea affects over 90% of symptomatic patients, with flatulence in about 75% and abdominal pain in about 78% [abdominal pain · diarrhoea · flatulence] - Vomiting occurs in about 40% and fever in about 27% of symptomatic cases, both less common than diarrhea [diarrhoea · fever · vomiting] - Bloody diarrhea is uncommon, occurring in under 12%, and should raise concern for another cause [bloody diarrhoea · diarrhoea] - Symptoms usually begin one to two weeks after exposure and may clear on their own within one to four weeks - Up to 40% of patients develop temporary lactose intolerance from gut lining damage - Extraintestinal features such as hives, painful urination, joint pain, or eye symptoms occur mainly in chronic cases [burning on passing urine · joint pain · urticaria] - The typical picture is bloating and abdominal distension alongside the diarrhoea, the flatulence and the pain [abdominal distension · diarrhoea · flatulence] - Carrying it with no symptoms at all is also common - In some patients it becomes chronic, and then it causes malabsorption and weight loss [weight loss] - It is one of the commonest treatable causes of gastroenteritis in the world, and the burden falls hardest on low-income countries - The organism is a protozoan parasite, Giardia duodenalis - In high-income countries the risks named are international travel, untreated freshwater, male- to-male sexual contact, contact with children in nappies, recent antibiotics, and existing chronic bowel disease SIGNS - what you find (3) - Examination findings are usually unremarkable; dehydration signs may be present and fever is rarely seen [dehydration · fever] - Abdominal tenderness on palpation and increased bowel sounds (borborygmi) on auscultation may be found [abdominal tenderness] - Conjunctival redness or discharge, rash, or joint swelling may be seen on exam as extraintestinal signs [eye redness · joint swelling · rash] TESTS (4) - Stool microscopy for trophozoites or cysts is the traditional test, though newer methods are now preferred - Testing three stool samples collected over several days improves detection sensitivity - Stool antigen testing is about 92% sensitive, while PCR-based testing reaches up to 99% - Routine blood counts and electrolytes are usually normal, and eosinophilia is rarely seen IF NOT THIS - what else fits (4) - Cyclospora or Cystoisospora infection is on the differential for giardiasis - Irritable bowel syndrome is on the differential for giardiasis - Inflammatory bowel disease is on the differential for giardiasis - Viral gastroenteritis is on the differential for giardiasis Source StatPearls "Giardiasis" - disease-level clinical article Status traced to the source above 1. METRONIDAZOLE [1st line] Adult 250-500 mg TID for 5-7 days or single 2 g daily dose for 3 days x 3-7 days Peds 15-30 mg/kg/day [child max 1200 mg] (Divided TID for 5-7 days) 3kg -> 45-90 mg/day 4kg -> 60-120 mg/day 5kg -> 75-150 mg/day 6kg -> 90-180 mg/day 7kg -> 105-210 mg/day 8kg -> 120-240 mg/day 9kg -> 135-270 mg/day 10kg -> 150-300 mg/day 11kg -> 165-330 mg/day 12kg -> 180-360 mg/day 13kg -> 195-390 mg/day 14kg -> 210-420 mg/day 15kg -> 225-450 mg/day 16kg -> 240-480 mg/day 17kg -> 255-510 mg/day 18kg -> 270-540 mg/day 19kg -> 285-570 mg/day 20kg -> 300-600 mg/day 21kg -> 315-630 mg/day 22kg -> 330-660 mg/day 23kg -> 345-690 mg/day 24kg -> 360-720 mg/day 25kg -> 375-750 mg/day 26kg -> 390-780 mg/day 27kg -> 405-810 mg/day 28kg -> 420-840 mg/day 29kg -> 435-870 mg/day 30kg -> 450-900 mg/day 31kg -> 465-930 mg/day 32kg -> 480-960 mg/day 33kg -> 495-990 mg/day 34kg -> 510-1020 mg/day 35kg -> 525-1050 mg/day 36kg -> 540-1080 mg/day 37kg -> 555-1110 mg/day 38kg -> 570-1140 mg/day 39kg -> 585-1170 mg/day 40kg -> 600-1200 mg/day 41kg -> 615-1200 mg/day (upper capped) 42kg -> 630-1200 mg/day (upper capped) 43kg -> 645-1200 mg/day (upper capped) 44kg -> 660-1200 mg/day (upper capped) 45kg -> 675-1200 mg/day (upper capped) 46kg -> 690-1200 mg/day (upper capped) 47kg -> 705-1200 mg/day (upper capped) 48kg -> 720-1200 mg/day (upper capped) 49kg -> 735-1200 mg/day (upper capped) 50kg -> 750-1200 mg/day (upper capped) Source Egyptian National Drug Formulary - Antimicrobial 2023 (metronidazole monograph) Why Nitroimidazole antiprotozoal that is activated inside the parasite to damage its DNA; the standard, inexpensive first-line treatment for giardiasis. Caution Avoid alcohol completely during treatment. Treat all household contacts if symptomatic. Nausea and metallic taste are common. Egypt TRICHOGYL 250 MG 20 TAB. EL NASR 4.35 EGP (0.22/unit) FLAGICURE 250MG 20 TAB. KAHIRA 7.00 EGP (0.35/unit) TRICHOCID 250MG 20 TAB. CID 7.00 EGP (0.35/unit) METRONIDAZOLE-MUP 250 MG 20 F.C. TABS. MUP 11.00 EGP (0.55/unit) AMRIZOLE 250 MG 20 TABS. AMRIYA 20.00 EGP (1.00/unit) METROZOLE 250MG 20 TAB. MEMPHIS 20.00 EGP (1.00/unit) DUMOZOL 125MG/5ML SUSP. 125ML MINA PHARM > ... 5.75 EGP -> ? strength differs, ? different route - not oral solid METROZOLE 125MG/5ML SUSP. 120 ML MEMPHIS 19.50 EGP -> ? strength differs, ? different route - not oral solid 2. TINIDAZOLE [1st line] Adult 2 g single dose taken with food - single-dose Peds 50 mg/kg/dose [child max 2000 mg] (Single dose with food) Age restriction: minimum 36 months 3kg -> 150 mg/dose 4kg -> 200 mg/dose 5kg -> 250 mg/dose 6kg -> 300 mg/dose 7kg -> 350 mg/dose 8kg -> 400 mg/dose 9kg -> 450 mg/dose 10kg -> 500 mg/dose 11kg -> 550 mg/dose 12kg -> 600 mg/dose 13kg -> 650 mg/dose 14kg -> 700 mg/dose 15kg -> 750 mg/dose 16kg -> 800 mg/dose 17kg -> 850 mg/dose 18kg -> 900 mg/dose 19kg -> 950 mg/dose 20kg -> 1000 mg/dose 21kg -> 1050 mg/dose 22kg -> 1100 mg/dose 23kg -> 1150 mg/dose 24kg -> 1200 mg/dose 25kg -> 1250 mg/dose 26kg -> 1300 mg/dose 27kg -> 1350 mg/dose 28kg -> 1400 mg/dose 29kg -> 1450 mg/dose 30kg -> 1500 mg/dose 31kg -> 1550 mg/dose 32kg -> 1600 mg/dose 33kg -> 1650 mg/dose 34kg -> 1700 mg/dose 35kg -> 1750 mg/dose 36kg -> 1800 mg/dose 37kg -> 1850 mg/dose 38kg -> 1900 mg/dose 39kg -> 1950 mg/dose 40kg -> 2000 mg/dose 41kg -> 2000 mg/dose (capped) 42kg -> 2000 mg/dose (capped) 43kg -> 2000 mg/dose (capped) 44kg -> 2000 mg/dose (capped) 45kg -> 2000 mg/dose (capped) 46kg -> 2000 mg/dose (capped) 47kg -> 2000 mg/dose (capped) 48kg -> 2000 mg/dose (capped) 49kg -> 2000 mg/dose (capped) 50kg -> 2000 mg/dose (capped) Choice The source names tinidazole as the most effective agent for giardiasis, with nitazoxanide as the alternative. Source Tindamax (tinidazole) US prescribing information, Dosage and Administration - Giardiasis (DailyMed, Mission Pharmacal) Why Nitroimidazole in the same class as metronidazole but with a longer half-life allowing a shorter course, offered as an alternative for patients wanting a simpler regimen. Caution Avoid alcohol during and for 3 days after dose. Take with food. The label licenses the paediatric single dose from 3 years, not below. Not in the first trimester of pregnancy. Later in pregnancy weigh it case by case, and stop breastfeeding for the dose and 3 days after - it stays in milk that long. Egypt FASIGYN 500 MG 4 TABS. PFIZER 8.35 EGP (2.09/unit) PROTOZOLE 500 MG 12 F.C.TABS. MUP 39.00 EGP (3.25/unit) 3. NITAZOXANIDE [1st line] Adult 500 mg BID with food x 3 days Peds 1 to 3 years: 100 mg twice daily with food, for 3 days 4 to 11 years: 200 mg twice daily with food, for 3 days (100 mg BID (1-3 yrs) or 200 mg BID (4-11 yrs) with food for 3 days) Source ALINIA (nitazoxanide) US prescribing information, section 2.1 Recommended Dosage, Table 1 (DailyMed SetID e90f98d9-3c9b-4e75-ba18-5517283eadf0) Why Antiprotozoal that interferes with the parasite's electron transfer enzyme system; a useful alternative to the nitroimidazoles, particularly convenient in Egypt where it is available as a paediatric suspension. Caution Take with food. Nitazoxanide is an excellent pediatric option available as suspension in Egypt. Urine discoloration can occur. Egypt UNINITAPROZAX 500MG 12 F.C. TAB. UNIPHARMA CO.... 16.00 EGP (1.33/unit) CRYPTOPER 500MG 30 F.C. TAB. EGPI > TAG PH... 56.00 EGP (1.87/unit) XEROVIRINC 500MG 18 F.C. TAB. MINA PHARM 42.00 EGP (2.33/unit) PARAZOXANIDE 500 MG 18 CAP. MISR > PHARMA... 63.00 EGP (3.50/unit) TRUSTNAL 500 MG 10 F.C. TABS. ADWIA 40.00 EGP (4.00/unit) NIT CLEAN 500MG 12 F.C. TABS. WESTERN PHARM... 72.00 EGP (6.00/unit) CRYPTONAZ 500MG 12 F.C.TAB. COPAD PHARMA 82.00 EGP (6.83/unit) NIT CLEAN 500MG 5*6 F.C. TABS. WESTERN PHARM... 180.00 EGP (30.00/unit) UNINITAPROZAX 100MG/5ML SUSP. 60ML UNIPHARMA CO. > UNIPHARMA 6.00 EGP -> ? strength differs, ? different route - not oral solid ZOLIFUTAL 100MG/5ML SUSP. 60 ML FUTURE PHARMA... 13.50 EGP -> ? strength differs, ? different route - not oral solid Prices are indicative (dataset snapshot 2026-06); verify with the pharmacy. ``` --- Dawaa Reference is a reference for prescribers, not a medical device, and does not replace clinical judgement. [Privacy policy](/privacy)