Question 10

Drowsiness is a common side effect of diphenhydramine.

Diphenhydramine is an antihistamine that often leads to drowsiness as a side effect due to its sedative properties, which can affect the central nervous system.

A) Bradycardia

Bradycardia, or a slower than normal heart rate, is not commonly associated with diphenhydramine. While some medications can influence heart rate, diphenhydramine primarily affects histamine receptors and induces sedation rather than significantly impacting heart rate.

B) Hypertension

Hypertension, or high blood pressure, is not a recognized common side effect of diphenhydramine. Instead, antihistamines like diphenhydramine are more likely to cause sedation rather than an increase in blood pressure.

C) Joint pain

Joint pain is not a typical side effect of diphenhydramine. This medication is primarily used for allergies and sleep aid, and joint pain does not align with the pharmacological effects or common adverse reactions associated with its use.

D) Drowsiness

Drowsiness is a well-documented and common side effect of diphenhydramine. This occurs due to its ability to cross the blood-brain barrier and block histamine receptors in the brain, leading to sedative effects.

Conclusion

Drowsiness stands out as the definitive common side effect of diphenhydramine, clearly supported by its pharmacological action as a sedating antihistamine. In contrast, the other options, including bradycardia, hypertension, and joint pain, do not align with the expected side effects or mechanism of action of this medication, reinforcing the validity of the correct answer.