8 Medicines That Don't Mix With Alcohol

Potential reactions with alcohol: Occasional drinking may lead to internal bleeding; heavier drinking may cause bleeding or may have the opposite effect, resulting in blood clots, stroke or heart attack, according to the NIAAA. "The liver makes proteins that help the blood to clot, which is why even social drinkers need to be careful when taking Coumadin," explains Amy Tiemeier, associate professor of pharmacy practice at St. Louis College of Pharmacy.

4. Antibiotics

Such as: Zithromax (often called Z-Paks), Flagyl, Nizoral

Potential reactions with alcohol: fast heartbeat; sudden changes in blood pressure; stomach pain; vomiting; headache; and liver damage (with Nizoral). While numerous antibiotics don't interact dangerously with alcohol, some do. Alcohol also can make common unpleasant symptoms of antibiotics (upset stomach, dizziness and so on) worse, as well as reduce your energy, so it takes longer to recover from whatever is making you sick, says the Mayo Clinic.

5. Diabetes meds

Such as: Glucotrol, Glynase, Micronase, Diabinese

Potential reactions with alcohol: Blood sugar levels fall to dangerously low levels; "flushing reaction" that involves nausea, vomiting, blood pressure issues, headaches and a racing heartbeat. "These medications can actually block the breakdown of alcohol," explains Nelson.

Over-the-Counter Meds

6. Nonprescription pain meds

Such as: Tylenol, Advil, Aleve, Excedrin, Motrin

Potential reactions with alcohol: stomach upset, bleeding and ulcers; liver damage (acetaminophen, like Tylenol, and Excedrin); rapid heartbeat. "Tylenol at excessive doses can cause liver damage, and alcohol can make it cause that damage at lower levels," says Rabia Atayee, associate clinical professor of pharmacy at UC San Diego Health. Also, many prescription meds, like Norco, contain acetaminophen, so it's important to be mindful of taking them with alcohol. On the advice of an expert panel that reviewed new information about nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen and their risks, the Food and Drug Administration in 2015 strengthened its warnings of heart attack and stroke risk increase even with short-term use, and warned the risk may begin within a few weeks of starting to take an NSAID. "Toxicities in both the heart and stomach lining can happen faster than we once thought," says Atayee.

7. Allergy and cold & flu meds

Such as: Benadryl, Claritin, Claritin-D, Dimetapp, Zyrtec, Sudafed Sinus and Allergy, Tylenol Allergy Sinus, Tylenol Cold & Flu

Potential reactions with alcohol: increased drowsiness, dizziness, liver damage from drugs containing acetaminophen. Another caveat: Many popular cold, flu and allergy remedies contain more than one ingredient that can react with alcohol. The NIAAA recommends reading the label on the medication bottle to find out exactly what ingredients a medicine contains, and asking your pharmacist if you have any questions about how alcohol might interact with a drug you are taking.

8. Cough Syrup

Such as: Robitussin Cough, Robitussin A-C

Potential reactions with alcohol: Drowsiness or dizziness. Remember that certain cough medicines contain up to 10 percent alcohol, according to the NIAAA, so imbibing in addition could greatly increase those side effects. "Patients who combine the two should never drive or operate heavy machinery afterward," says Tiemeier. What's more, if you're taking a prescription cough syrup with codeine, it could result in double the trouble because the codeine (a narcotic) and the alcohol have many of the same effects on the brain.