Drug Interactions: 3 Problem Combinations to Avoid

Be cautious about these drug duos.

A recent study underscores the need for care if you take more than a single drug. Many heart attack patients get two clot-busters to ward off another attack, plus a proton pump inhibitor to prevent the stomach upset and bleeding that those meds can cause. But researchers recently reported that adding the stomach-soothing drug undoes some of the clot-busting benefit -- so the risk of a second heart attack jumps about 25 percent. Dangerous interactions are more common than you think, says Todd Semla, PharmD, who heads the board of directors of the American Geriatrics Society. Be cautious about these drug duos:

You Have: An infection
You Take: A quinolone antibiotic (such as levofloxacin) plus an antacid that contains calcium, magnesium, or aluminum (such as Tums, Maalox, and Mylanta)
You Risk: These antacids can decrease the absorption of quinolones by as much as 90 percent.
Do This: Take your antibiotic two hours before or six hours after the antacid.

You Have: High cholesterol
You Take: Certain statin drugs (such as lovastatin) plus a macrolide antibiotic (such as clarithromycin) or an oral azole antifungal (such as ketoconazole)
You Risk: These drugs for bacterial or fungal infection may raise blood levels of many cholesterol meds, increasing the risk of muscle or kidney damage.
Do This: Be alert to symptoms like muscle weakness or pain.

You Have: High blood pressure
You Take: An ACE inhibitor (such as lisinopril) plus potassium supplements
You Risk: The combo can boost potassium levels high enough to cause abnormal heart rhythms.
Do This: If you need both, get your potassium levels checked every few months.