Which of these medications is an anticonvulsant?

The medication Klonopin, known generically as clonazepam, is classified as an anticonvulsant. It is primarily used to treat seizure disorders, specifically in the management of certain types of seizures in patients with epilepsy. Klonopin works by enhancing the effects of a neurotransmitter called gamma-aminobutyric acid (GABA), which helps to calm excessive neuronal activity in the brain that can lead to seizures.

The other medications listed do not serve the purpose of treating seizures. Rolaids is an antacid used to relieve heartburn and indigestion. Prevacid, known generically as lansoprazole, is a proton pump inhibitor used to treat conditions like gastroesophageal reflux disease (GERD) by reducing stomach acid production. Tylenol, or acetaminophen, is a pain reliever and fever reducer, primarily used for mild to moderate pain relief and to lower fever. Thus, Klonopin stands out as the correct answer for its role in managing epileptic conditions and preventing seizures.