Key takeaways
Benzonatate (Tessalon Perles) and promethazine (Phenergan) are both prescription medications, but they belong to different drug classes and treat different conditions. Benzonatate is an antitussive used to relieve cough in people aged 10 and older, while promethazine is an antihistamine used for a variety of conditions, including allergies, nausea, and motion sickness. However, promethazine is also found in some prescription cough syrups. Benzonatate is taken orally in capsule form, typically three times a day, and is available as a generic. Promethazine comes in multiple forms, including tablets, oral solutions, rectal suppositories, and injections, and its dosing varies based on the condition being treated. Benzonatate can cause drowsiness, headache, and constipation, while promethazine may lead to drowsiness, dizziness, and dry mouth. Because both medications can cause drowsiness you should avoid alcohol and be cautious when driving. Promethazine has more potential drug interactions, especially with medications like MAOIs.
