What the label lists and what reports show
Tinidazole side effects
Tinidazole's FDA label: “The most common adverse reactions in treated patients (incidence >2%), which were not identified in the trichomoniasis, giardiasis and amebiasis studies, are gastrointestinal: decreased appetite, and flatulence; …” FAERS holds 438 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nausea (28 reports).
- Generic listed
- Boxed warning
Check it at the source: the tinidazole FDA label on DailyMed (effective December 27, 2021, Mission Pharmacal Company); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsThe most common adverse reactions in treated patients (incidence >2%), which were not identified in the trichomoniasis, giardiasis and amebiasis studies, are gastrointestinal: decreased appetite, and flatulence; renal: urinary tract infection, painful urination, and urine abnormality; and other reactions including pelvic pain, vulvo-vaginal discomfort, vaginal odor, menorrhagia, and upper respiratory tract infection [See Clinical Studies (14.5)].
Table 1. Adverse Reactions Summary of Published Reports
| Reaction | 2 g single dose | Multi-day dose |
|---|---|---|
| GI: Metallic/bitter taste | 3.7% | 6.3% |
| Nausea | 3.2% | 4.5% |
| Anorexia | 1.5% | 2.5% |
| Dyspepsia/cramps/epigastric discomfort | 1.8% | 1.4% |
| Vomiting | 1.5% | 0.9% |
| Constipation | 0.4% | 1.4% |
| CNS: Weakness/fatigue/malaise | 2.1% | 1.1% |
| Dizziness | 1.1% | 0.5% |
| Other: Headache | 1.3% | 0.7% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedADVERSE REACTIONS 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Among 3669 patients treated with a single 2 g dose of tinidazole, in both controlled and uncontrolled trichomoniasis and giardiasis clinical studies, adverse reactions were reported by 11.0% of patients. For multi-day dosing in controlled and uncontrolled amebiasis studies, adverse reactions were reported by 13.8% of 1765 patients. Common (≥ 1% incidence) adverse reactions reported by body system are as follows. (Note: Data described in Table 1 below are pooled from studies with variable designs and safety evaluations.) Other adverse reactions reported with tinidazole include: Central Nervous System: Two serious adverse reactions reported include convulsions and transient peripheral neuropathy including numbness and paresthesia [see Warnings and Precautions (5.1)]. Other CNS reports include vertigo, ataxia, giddiness, insomnia, drowsiness.
Source: FDA drug label, Mission Pharmacal Company, effective December 27, 2021 (SPL set a0d01539-8413-4703-94cc-d221918630a1), via openFDA; the full label on DailyMed
What do FAERS reports show?
438 reports list tinidazole among the medicines taken, each a report of something that happened, not proof the medicine caused it; 20 are coded as a death and 129 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 12 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Tinidazole: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions