Which of the following is a primary action of Bethanechol on the urinary system?

Bethanechol primarily acts as a muscarinic agonist, which means it stimulates the muscarinic receptors found in the smooth muscle of the bladder. One of its key actions is stimulating the contraction of the bladder wall, or the detrusor muscle. This contraction is essential for promoting urination, particularly in individuals with urinary retention or atony of the bladder, as it enhances the ability to expel urine from the bladder.

The effect on the bladder wall contributes to increased intravesical pressure, thus facilitating the process of micturition. This is particularly useful in clinical settings where patients may have difficulty urinating due to conditions such as postoperative urinary retention or neurogenic bladder disorders.

While relaxation of the internal sphincter may assist in the process of urination, Bethanechol's primary and most significant action is in promoting bladder contraction. Therefore, focusing on how Bethanechol augments bladder wall contraction highlights its distinct role as a cholinergic agent in the management of urinary conditions.