Drug Interaction Checker

Limit caffeine intake (examples: coffee, teas, colas, chocolate and some herbal supplements) while taking Phenylephrine. Also avoid medicines containing additional Caffeine whenever possible. Side effects from Phenylephrine may get worse if you take excessive Caffeine. Taking a high amount of Caffeine can increase the risk of nausea, nervousness, palpitations, problems with sleep, rapid heartbeat, tremor, or other side effects.

Tobacco smoking may reduce the effectiveness of this drug in treating your condition; Tobacco smoke contains substances that speed the removal of this drug from the body. Alternatively, if you take this drug and suddenly stop Tobacco smoking, you may feel more drowsy or tired, or may experience confusion, dizziness, difficulty in movement or other side effects. If you will stop smoking, use care in driving or operating machinery until you know how this drug will affect you. Make sure your prescriber is aware that you smoke Tobacco or if you plan to stop smoking. Report any unusual side effects promptly.