Glyceryl trinitrate is given by sublingual route because of-
Ans. is 'b' i.e., Hepatic first pass metabolism o This question is tricky one as option b & c literally have the same meaning, i.e. any drug with high hepatic first pass metabolism will have lower oral bioavailability. o But, we use sublingual nitroglycerine to produce immediate relief of symptoms in angina By sublingual route there is direct absoiption into systemic circulation bypassing liver. "The sublingual route is used when terminating an attack or aboing an imminent one is the aim. The tablet may be crushed under the teeth and spread over buccal mucosa. It acts within 1-2 min because of direct absorption into systemic circulation (bypassing liver where almost 90% is metabolized)"
Sho t1/2 in plasma
Hepatic first pass metabolism
Lower bioavailability by oral route
Extensive protein binding