Question

Rita, a 50-year old homemaker, suffers from insomnia, which is worsened by the fact that she has seasonal allergies. As she does not have a driver’s licence, her son takes her to the doctor, though she is very prone to becoming nauseous when she is a passenger. Her doctor has recommended using an antihistamine to alleviate all three issues. Suggest an appropriate antihistamine to use for all three of her conditions, and justify your answer by referring to pharmacodynamic and pharmacokinetic characteristics thereof.

Answer 1

An appropriate antihistamine to use for Rita’s insomnia, seasonal allergies, and nausea is diphenhydramine (Benadryl). This is an antihistamine usually used for the treatment of seasonal allergies, which also alleviates insomnia and nausea. Diphenhydramine is an inverse agonist that acts at the H1 receptor, to reverse the effect of histamine on capillaries and to reduce symptoms of allergic reaction. The action of diphenhydramine as an intracellular sodium channel blocker gives it the properties of a local anesthetic.