Medications cure giardiasis in adults 80% to 95% of the time.¹ But some people may not respond to the first course of medicine and may need to repeat the treatment with the same or another medicine.

If symptoms and medical history strongly suggest a diagnosis of giardiasis, some doctors may prescribe medicine before doing further testing. But this decision depends on whether family members, for example, were exposed at the same time or whether there is a risk of spreading the infection to others.

Medication Choices

Antiprotozoals (such as metronidazole or tinidazole)

Albendazole (such as Albenza or Valbazen)

Nitazoxanide (Alinia, approved for use in children and adults)

Furazolidone (alternate medicine for children)

Paromomycin (alternate medication for pregnant women)

Paromomycin may be used during pregnancy, although most doctors prefer not to prescribe medications during the first 3 months of pregnancy.

What To Think About

If the first course of medicine does not cure the infection, the treatment may be repeated with the same medicine, another one, or a combination of medicines.