👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Pharmacological Therapies🔖 Free to read, print, and share
Also known as: Flagyl · metronidazole · metro · C. diff antibiotic · trichomoniasis drug
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Use this quick-reference guide to spot, treat, and prevent Metronidazole on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
📌 Use
C. diff, anaerobes, trichomonas
Giardia, bacterial vaginosis
📌 Avoid
NO alcohol → disulfiram: flushing, vomiting
Avoid 3 days after last dose
🎓 Teach
Metallic taste, dark/red urine
Take with food → ↓GI upset
🚩 Report
Numbness → peripheral neuropathy
Seizures, severe headache
📚 Metronidazole — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Metronidazole treats anaerobic bacterial infections, C. difficile colitis, trichomoniasis, bacterial vaginosis, and giardiasis. Its hallmark is a severe disulfiram-like reaction with alcohol, so alcohol must be strictly avoided. The key principle is no alcohol during therapy and for at least 48 to 72 hours afterward.
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Key points
Understand these first
Metronidazole is effective against anaerobic bacteria and protozoa.
It causes a severe disulfiram-like reaction (flushing, severe nausea, vomiting, tachycardia) when combined with alcohol.
Alcohol must be avoided during therapy and for at least 48 to 72 hours after the last dose.
It commonly causes a metallic taste, nausea, and harmless darkening of the urine.
It can potentiate warfarin and increase bleeding risk.
For trichomoniasis, sexual partners are treated at the same time to prevent reinfection.
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Nursing priorities
What to do, in order
Screen for and emphasize complete avoidance of alcohol including in mouthwash and cough syrups.
Monitor INR in patients taking warfarin and assess for bleeding.
Assess for and report CNS effects such as numbness, tingling, or seizures.
Teach that treating sexual partners is needed for trichomoniasis.
Take with food to reduce GI upset.
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Red flags — report now
Escalate immediately
Severe flushing, vomiting, and palpitations after alcohol indicate a disulfiram-like reaction and require evaluation.
Numbness, tingling, or seizures may indicate neurotoxicity and must be reported.
Increased bruising or bleeding in patients on warfarin should be reported.
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Labs & values
Numbers to know
INR 0.8-1.1 (rises when combined with warfarin)
WBC 5,000-10,000/mm3 (monitor for response and bone marrow effects)
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Patient teaching
What patients must know
Do not drink any alcohol during treatment and for at least 3 days after the last dose, and check cough syrups and mouthwash for alcohol.
Your urine may turn dark, which is harmless, and you may notice a metallic taste.
If treated for a trichomonas infection, your partner must be treated too.
Report numbness, tingling, or seizures, and take with food to reduce stomach upset.
❓ Metronidazole: NCLEX FAQs
What are the priority nursing interventions for Metronidazole?
Screen for and emphasize complete avoidance of alcohol including in mouthwash and cough syrups. Monitor INR in patients taking warfarin and assess for bleeding. Assess for and report CNS effects such as numbness, tingling, or seizures. Teach that treating sexual partners is needed for trichomoniasis.
What are the warning signs of Metronidazole a nurse must report?
Severe flushing, vomiting, and palpitations after alcohol indicate a disulfiram-like reaction and require evaluation. Numbness, tingling, or seizures may indicate neurotoxicity and must be reported. Increased bruising or bleeding in patients on warfarin should be reported.
What do I need to know about Metronidazole for the NCLEX?
Metronidazole is effective against anaerobic bacteria and protozoa. It causes a severe disulfiram-like reaction (flushing, severe nausea, vomiting, tachycardia) when combined with alcohol. Alcohol must be avoided during therapy and for at least 48 to 72 hours after the last dose. It commonly causes a metallic taste, nausea, and harmless darkening of the urine.
What patient teaching is important for Metronidazole?
Do not drink any alcohol during treatment and for at least 3 days after the last dose, and check cough syrups and mouthwash for alcohol. Your urine may turn dark, which is harmless, and you may notice a metallic taste. If treated for a trichomonas infection, your partner must be treated too. Report numbness, tingling, or seizures, and take with food to reduce stomach upset.
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Quick Tip
Metronidazole is effective against anaerobic bacteria and protozoa.