Question

For for each of the following drugs, list the therapeutic indication and the mechanism of action:

a. rifampin b. loratadine c. phenylephrine

d. varenicline e. fexofenadine​​​​​​​   f. mometasone

Answer 1

a. Rifampicin: It is used as an antibiotic to treat bacterial infections, including tuberculosis, and leprosy. It acts by inhibiting RNA synthesis or transcription by binding to the -subunit of RNA polymerase, thereby blocking elongation of RNA transcripts.

b. loratadine: It is used for the treatment of allergies. It acts as a anti-histamine that blocks histamine receptor (H1 receptor) thereby preventing allergic symptoms such as welts, itching swelling of tissues.

c. Phenylephrine: It is used to treat nasal congestions, caused during cold, or allergies. This drug mimics the action of epinephrine and binds to alpha-1 receptors causing constriction of bloo dvessels.

d. varenicline: It is used to treat nicotine addiction. It is a partial agonist of nicotinic acetylcholine receptor and attenuates the craving for nicotine.

e. fexofenadine: It is also an anti-histamine drug that is used to treat allergic symptoms such as hay fever. It acts by blocking the H1 receptor thereby preventing their activation by histamine and hence preventing the symptoms associated with allergies.

f. momethasone: It is a steroid based drug, used to treat hay fever, asthma.