2nd August 2023

A 44 year old man presents with a 4 day history of foul-smelling diarrhoea and crampy abdominal pain.

A 44 year old man presents with a 4 day history of foul-smelling diarrhoea and crampy abdominal pain. He tells you the stools look pale and float in the toilet bowl. He returned from a trip to Ecuador 4 weeks ago. He is otherwise fit and well, with no past medical history. It is suspected he has giardiasis.

What is the initial first line treatment for the condition?

Select the SINGLE most appropriate option from the list below. Select ONE option only.