Which medication type is designed to control muscle contractions in the bladder?

The correct choice is antispasmodics, as these medications are specifically designed to relieve muscle spasms, including those in the bladder. In conditions such as overactive bladder or urinary incontinence, antispasmodics work by relaxing the smooth muscle in the bladder, thereby reducing involuntary contractions and providing better control over urination.

In contrast, antihypertensives are used to manage high blood pressure, and their action focuses primarily on the cardiovascular system rather than muscular control in the bladder. Antidepressants, while having various uses including some effects on bladder function, are not primarily aimed at controlling bladder contractions and are instead utilized for treating mood disorders. Lastly, antibiotics are intended for the treatment of infections and have no direct role in controlling muscle contractions in any organ, including the bladder.