Metronidazole
Giardiasis can usually be successfully treated with a medicine called metronidazole. Metronidazole works by killing the parasites that cause giardiasis.
Metronidazole is usually taken in tablet form with most people taking a seven-day course of medication.
Metronidazole does not usually cause any side effects. However, in rare cases, side effects of metronidazole can include:
- fits (convulsions),
- confusion, and seeing or hearing things that are not there (hallucinations),
- eyesight problems, such as blurred or double vision,
- skin rash,
- headache,
- dark urine,
- nausea,
- vomiting, and
- feeling sleepy or dizzy.
If you feel sleepy and dizzy while taking metronidazole, do not drive or operate complex or heavy machinery.
In very rare cases, some people experience a serious allergic reaction after taking metronidazole. You should immediately stop taking metronidazole and seek immediate medical advice if:
- your hands, feet, ankles, face, lips or throat become swollen,
- you have difficulty breathing,
- you have difficulty swallowing, or
- you develop an itchy, lumpy rash on your skin.
You should not drink alcohol while you are taking metronidazole, or for 48 hours after finishing your dose.
If you drink alcohol while taking metronidazole, you may experience symptoms that include:
- nausea,
- vomiting,
- stomach pain,
- hot flushes,
- headache, and
- rapid heartbeat.
If you are diagnosed with giardiasis, other members of your household may be advised to have treatment with metronidazole. This may be recommended as a precautionary measure just in case they have also been infected. Your GP will be able to advise you whether treatment is necessary.
