Which option correctly identifies Sublingual as a route among the following?

• A. Oral
• B. Subcutaneous
• C. Intramuscular
• D. Sublingual

Answer: (D)

Understanding routes of administration and how sublingual absorption works is the key. The sublingual route means placing the drug under the tongue so it is absorbed directly through the oral mucosa into the bloodstream. This yields rapid onset because the area under the tongue has rich blood vessels and bypasses the liver’s first-pass metabolism, which can reduce or delay effects if the drug were swallowed.

This is different from the oral route, where a swallowed tablet or liquid must travel through the digestive system and liver before reaching systemic circulation, often slowing onset and reducing active drug levels. It’s also not an injectable route—subcutaneous or intramuscular—where the drug is deposited into tissue and then absorbed more slowly into the bloodstream.

So, the correct choice is the one that names Sublingual as the route, because it uniquely describes absorption through the under-tongue mucosa with rapid systemic uptake and bypass of first-pass metabolism. For context, nitroglycerin tablets are commonly given sublingually for quick relief of angina due to this rapid absorption.