Which two classes of drugs are known to cause tachycardia?

The correct answer involves mydriatics and anticholinergics, which are known to cause tachycardia due to their pharmacological effects on the autonomic nervous system. Mydriatics, which are used to dilate the pupil, often exert their action by blocking the muscarinic receptors in the eye, leading to increased sympathetic tone and potentially elevating the heart rate.

Anticholinergics also block acetylcholine at muscarinic receptors, which can inhibit the parasympathetic nervous system's regular influence on heart rate control. This inhibition can result in an increase in heart rate or tachycardia as the sympathetic activity becomes more pronounced.

In contrast, the other classes mentioned do not typically cause tachycardia. For instance, miotics and beta-blockers usually lower heart rate, carbonic anhydrase inhibitors and prostaglandins have varied effects that do not typically include increased heart rate, and corticosteroids and diuretics typically do not have a direct impact on heart rate in the way that mydriatics and anticholinergics do.

Thus, understanding the mechanisms of mydriatics and anticholinergics clarifies their role in causing tachycardia