The Asthma Center

Asthma Medications and Side Effects

While taking medication, you may develop new symptoms which may or may not be related to one of your medications. In general, side effects fit within one of the following categories:

Pharmacological side effect

Most medications have more than one effect on the body. Although the main effect of the medication is used for treatment, other minor effects can lead to specific reactions. Learn about the common side effects of each of your medications before you begin taking them.

Increased sensitivity

You could be highly sensitive to certain classes of medication and therefore have a heightened response to the normal pharmacological action of these medications. You may need to sharply reduce your dose or switch to another drug.

Allergic reaction

You may develop an allergic reaction to medications. This reaction has nothing to do with the pharmacology (action) of the drug, but rather symptoms result from your unique response to the medication. Usually, you need to avoid all medications that are structurally similar. But if no alternative is available, you may undergo drug desensitization therapy.


You may have an underlying medical problem or unique metabolism that may produce unusual effects. For example, if you have a gastric ulcer, you may have major problems taking an oral corticosteroid since this medication may worsen your underlying ulcer disease. Antihistamines and decongestants may inhibit urination if you have an enlarged prostate. In each of these instances, your underlying medical problem or unique metabolism is related to the drug reaction.

Drug interaction

You may have a side effect when two medications are taken at the same time and one of these medications affects the action or metabolism of the other.

A Balancing Act

If you have chronic asthma, you'll probably need to take medication for a long time. Have your doctor periodically evaluate your condition, assess you understanding of the disease process and indepth knowledge of the actions and potential side effects of the medication prescribed.

The physician's task is to recommend the least risky medication which will be effective in controlling and/or preventing asthma symptoms. Because you are unique, it's not always possible to anticipate your precise benefits or exact risk of side effects of a medication. Further, the short- and long-term risks of asthma are often underestimated if you are undertreated. Therefore, your physician must weigh the pros and cons of your prescriptions throuhout your treatment.

If you start a new medication and then experience any unexpected symptoms, call the prescribing doctor to investigate possible side effects.