12 Medications You Should Never Mix Without Asking Your Doctor

7. Antihistamines and Sleeping Pills

Many over-the-counter antihistamines, like diphenhydramine (Benadryl), cause drowsiness. When taken with prescription sleeping medications like zolpidem (Ambien) or benzodiazepines, the sedative effects can become dangerously strong, leading to extreme drowsiness, confusion, dizziness, and even respiratory depression. If you're struggling with sleep issues, talk to your doctor about safer options.

8. St. John’s Wort and Birth Control Pills

St. John’s Wort, an herbal supplement often used for depression, can reduce the effectiveness of hormonal birth control, increasing the risk of unintended pregnancy. It speeds up the metabolism of estrogen and progestin, making birth control pills, patches, and implants less effective. If you're taking birth control and need mood support, speak with your doctor about alternative treatments.