Which type of medication is most likely to cause drowsiness as a side effect?

Antihistamines are known for causing drowsiness as a common side effect, particularly first-generation antihistamines such as diphenhydramine and chlorpheniramine. These medications work by blocking histamine receptors in the body, which can lead to sedation. The sedative effects can be utilized for conditions like allergic reactions or to promote sleep in specific situations.

In contrast, although analgesics can have sedative effects, particularly opioid analgesics, they are not primarily classified as medications that cause drowsiness in the same way antihistamines do. Corticosteroids generally do not cause sedation; instead, they may lead to restlessness or insomnia as side effects. Anticonvulsants may have a sedative effect in some patients, but they are primarily used to manage seizures and do not consistently produce drowsiness as a main action. Therefore, antihistamines are the most reliable group when considering medications specifically known for causing drowsiness.