> Western Medicines > Metronidazole


Used for: Rosacea
Chinese name:

What is Metronidazole for?

Metronidazole is an antibiotic and an antiprotozoal used for treating infections. The topical gel is also used to treat rosacea. 

Metronidazole can be used, including but not limited to, for treating the following medical conditions:

  • Anaerobic infections
  • H pylori eradication (in combination with other antibiotics and proton pump inhibitors)
  • Clostridioides difficile (C. diff) infection
  • Bacterial vaginosis
  • Pelvic inflammatory disease
  • Acute ulcerative gingivitis
  • Acute oral infections
  • Prevention of surgical infections
  • Invasive intestinal amoebiasis
  • Extra-intestinal amoebiasis (including liver abscess)
  • Urogenital trichomoniasis
  • Giardiasis

How to use it?

For treating infections, the typical adult dose of Metronidazole is 400 to 500 mg by mouth every 8 hours (3 times per day). Doses and duration will depend on the reason you are prescribed with Metronidazole. If you are using the vaginal gel, you should use 1 applicatorful into vagina daily at night for 5 days. 0.75% gel is also available for rosacea. You should apply a thin film to the affected area every morning and evening or use it as directed by your doctor.

What are the side effects of Metronidazole?

Common side effects of oral Metronidazole include dry mouth, nausea and vomiting, and metallic taste. When used on the skin, side effects may include dry skin and skin irritation. Those associated with vaginal use are pelvic discomfort and vaginal yeast infection. Anyone using any types of Metronidazole should avoid consuming alcohol as it can react with Metronidazole. Symptoms of the reaction with alcohol include nausea, vomiting, and flushing of the skin.

Who should not take Metronidazole?

  • People allergic to Metronidazole, nitroimidazole derivatives, or any formulation ingredients
  • Pregnant women (first trimester) with trichomoniasis

Pharmacist Tips:

  • Avoid exposure to sunlight or ultraviolet light after taking Metronidazole.
  • Do not use vaginal gel during menstruation.
  • Avoid consuming alcohol for while using Metronidazole and for 3 days after completing treatment.

Common dosing schedule:
Metronidazole should be taken with food to reduce stomach upset.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Metronidazole may interact with:

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Metronidazole in Hong Kong?

In Hong Kong, Metronidazole can be either a pharmacy only medicine or a prescription only medicine. For the injection forms, they are prescription only medicines and require a prescription from a doctor to be purchased in a pharmacy. They can also be obtained from doctors. For other forms, they are pharmacy only medicines and can be purchased without a prescription in a pharmacy by speaking with the pharmacist. They can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Metronidazole in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 0.75% (Gel)
  • 200mg/5ml (Oral Suspension)
  • 200mg / 400mg (Tablets)
Drug class
Sub class
Other drugs in same class
Used for: Rosacea
Chinese name:
Used for: Rosacea
Chinese name: