Mixing some medications can be fatal

by Joe Graedon and Teresa Graedon, Ph.D.

Most people know not to mix bleach and ammonia. Combining these cleaning products creates deadly chlorine gas. Occasionally an overzealous housecleaner forgets to read a label or overlooks this interaction with tragic results.

Mixing medications can be equally disastrous. A recent analysis in the journal Health Affairs notes that thousands of drugs can interact in a dangerous way. More than $70 billion is spent in the United States each year on treating the complications resulting from interactions and side effects.

Interactions often take people by surprise. The impotence pill Viagra is enormously popular. But more than 100 people have died after taking this medicine, which interacts in a deadly way with many heart medicines.

Other drugs also make Viagra more dangerous. One reader wanted to know if Viagra would be safe with his medicines: “I am taking Coumadin, Norvasc, Lanoxin, Lozol, quinidine, Accupril, Rezulin and insulin. I had a bad interaction with Sporanox and had to be hospitalized. I don’t want to repeat the experience.”

The anti-fungal drug Sporanox can make many medicines more toxic. Two of our reader’s drugs, Coumadin and Lanoxin, are adversely affected. Sporanox is also dangerous in combination with Viagra.

Grapefruit may also make Viagra risky. You won’t find this interaction in the pharmacist’s computer, however.

Many people assume that computer programs designed to catch hazardous combinations will protect them from serious drug interactions. Their confidence is misplaced.

Such programs get most of their information from drug companies, which are often slow to acknowledge interaction problems. It took years before pharmacists were notified that combining grapefruit with the antihistamines Seldane or Hismanal could result in fatal heart rhythm disturbances.

We worry that grapefruit together with the heartburn medicine Propulsid could have the same lethal consequences. Research has shown that grapefruit can have a profound impact on cholesterol-lowering drugs such as Mevacor, likely on Zocor and possibly Lipitor, as well as on blood pressure pills like Plendil, Procardia and Sular.

We are disappointed that pharmaceutical manufacturers and the Food and Drug Administration are slow to investigate potential interactions. When we bring such problems to their attention, they often fail to respond.

For example, there is no warning that Tylenol (acetaminophen) can make Coumadin more dangerous. Nor is there notice that aspirin or other arthritis pain relievers may interact with blood pressure medicines like Vasotec, Capoten, Accupril, Lotensin, and Zestril. Aspirin is a lifesaving medicine and should not be stopped, but people must monitor blood pressure carefully to make sure they are getting the expected benefit.

Someday we hope there will be a unified system for identifying incompatible drug mixtures before patients are harmed. It is long past due.

Joe Graedon is a pharmacologist.

Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their latest book is “The People’s Pharmacy: Completely New and Revised” (St. Martin’s Press).