Which medication is available in a sublingual form according to the patient's reported medications?

Nitroglycerin is available in a sublingual form, making it a critical medication for treating certain cardiovascular conditions, particularly angina pectoris. The sublingual route allows for rapid absorption into the bloodstream through the tissues under the tongue, providing quick relief from chest pain by dilating blood vessels and improving blood flow to the heart. This method is especially important in emergency situations where time is of the essence.

In contrast, aspirin, metformin, and ibuprofen are typically administered in different forms, such as orally in tablet or capsule forms. Aspirin is commonly used for pain relief and as a blood thinner but does not have a sublingual formulation. Metformin is primarily used for managing diabetes and is taken orally, usually in tablet form, and ibuprofen, an over-the-counter pain reliever, also comes in standard oral formats. Thus, the unique formulation and administration route of nitroglycerin distinguish it as the only medication in the list that is available in a sublingual form.