Narcotics that react with common medications include fentanyl, hydrocodone, hydromorphone, methadone and oxycodone, according to WebMD. Some medications also react with codeine, morphine and meperidine.
Fentanyl, like other opiates, commonly reacts with medications that cause drowsiness or affect breathing, including cough-and-cold products, sleeping pills, anti-seizure drugs, muscle relaxants and other narcotic pain relievers, notes WebMD. When taken with one or more of these medications, the risk of severe side effects increases. Additionally, MAO inhibitors produce potentially fatal reactions when taken alongside fentanyl. HIV medications, certain types of antibiotics, calcium channel blockers and azole antifungal medications have been known to affect the way fentanyl filters through the body.