Ornidazole

Sounds like 'or-nye-dah-zole'

Key points about ornidazole

  • Ornidazole is an antibiotic used to treat specific types of infections.
  • Find out how to take it safely and possible side effects.
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Ornidazole is an antibiotic used to treat infections caused by bacteria that don't require oxygen to grow and multiply (called anaerobic infections). Examples of such infections are amoebiasis, giardia, trichomoniasis and bacterial vaginosis. Ornidazole works by killing or stopping the growth of the bacteria. Like all antibiotics, ornidazole isn't effective against infections caused by viruses. 

In Aotearoa New Zealand, ornidazole comes as tablets (500 mg).

  • The dose of ornidazole will be different for different people, depending on the type of infection. 
  • The dose varies between one and three 500 mg tablets per dose depending on the type of infection you have. For some infections the dose may be once daily and others will be twice daily. 
  • Your doctor will advise you on how long to take ornidazole for (usually 1 to 10 days).
  • Always take your ornidazole exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions.

  • Timing: Take ornidazole tablets with or after food, at about the same time(s) each day. If you take them on an empty stomach, it may cause a stomach upset.
  • Alcohol: Don't drink alcohol while you're taking ornidazole and for at least 3 days after finishing treatment. Drinking alcohol with ornidazole may make you nauseous (feel sick), vomit (be sick), have stomach cramps, headaches and flushing.
  • Missed dose: If you forget to take your dose, take it as soon as you remember. But if it is nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.
  • Finish the course: It's best to take the whole course of antibiotics for the number of days your doctor has told you to. Don't stop taking it, even if you feel your infection has cleared up. Talk to your doctor first.

Like all medicines ornidazole can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sick (nausea) or vomiting
  • Take ornidazole with food.
  • Don't drink alcohol while you're taking ornidazole and for 3 days after treatment.
  • Tell your doctor if these bother you.
  • Headache
  • Dry mouth
  • Food tastes different
  • These are quite common when you first start taking ornidazole.
  • Tell your doctor if these side effects bother you. 
  • Confusion or dizziness
  • Don't drive until it feels safe to do so.
  • Tell your doctor.
  • Vaginal itching, soreness or discharge (thrush)
  • Tell your doctor or pharmacist.
  • Signs of problems with your liver such as yellowing of the skin or eyes, dark urine, pain in the abdomen
  • Tell your doctor immediately or phone Healthline 0800 611 116. 
  • Signs of an allergic reaction such as skin rash, itching, swelling of your lips, face, and mouth or difficulty breathing
  • Tell your doctor immediately or phone Healthline 0800 611 116. 

Read more about medicines and side effects and reporting a reaction you think might be a side effect.

Ornidazole(external link) New Zealand Formulary Patient Information

Brochures


Advice if your child is prescribed an antibiotic [PDF, 98 KB] BPAC, NZ
Advice if you are prescribed an antibiotic [PDF, 107 KB] BPAC, NZ, 2024

References

  1. Ornidazole(external link) New Zealand Formulary
  2. Ornidazole(external link) New Zealand Formulary for Children

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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