Which of the following medications is administered through the sublingual route?

Insulin is primarily administered via subcutaneous injections or insulin pumps, as it is a peptide hormone that cannot effectively pass through the digestive system or mucous membranes. This route ensures that insulin is delivered directly into the bloodstream for effective regulation of blood glucose levels.

Penicillin is typically administered via intramuscular or intravenous routes, as it is an antibiotic that needs to reach effective concentrations in the bloodstream to combat infections. Sublingual administration is not suitable for penicillin due to its formulation and stability requirements.

Heparin is usually given through subcutaneous or intravenous routes, as it is an anticoagulant that requires precise dosing and monitoring within the bloodstream. The sublingual route is not appropriate for heparin because it does not provide the necessary control over its anticoagulant effects.