When is antibiotic treatment recommended for giardiasis?

Giardiasis is caused by a microscopic parasite affecting the small intestine. It can cause watery or greasy diarrhoea, gas, cramps, nausea, tiredness and weight loss. Some people have few symptoms and may not need immediate medicine, while persistent or troublesome illness is more likely to prompt a prescription. Choice and timing depend on symptoms, test results, age, pregnancy, other illnesses and medicines. A clinician may request stool samples because several causes of diarrhoea can look similar.

Drink frequent fluids and use oral rehydration advice if diarrhoea is heavy. Wash hands with soap and water after using the toilet and before handling food; avoid preparing food for others while unwell. Take the prescribed medicine exactly as directed, and do not share leftover antibiotics. If symptoms continue after treatment, contact the clinician because reinfection, treatment failure or another diagnosis may need checking. People in the same household may need advice if several develop diarrhoea.

Arrange prompt assessment for dehydration, very little urine, dizziness, blood in stool, severe abdominal pain, fever, ongoing vomiting or diarrhoea that does not settle. Children, older adults, pregnant people and people with weakened immunity can become unwell more quickly. Seek emergency help for confusion, collapse, inability to keep fluids down or severe weakness.

Ask whether stool testing is needed, why medicine is recommended in your situation, how to take it with food or other medicines, and when symptoms should improve. Ask when you can return to work or school, what hygiene precautions to follow, and whether a repeat test is needed if diarrhoea continues.