Preventing hypersensitivity reactions

There are few screening tests that can identify who might be at risk for drug-induced hypersensitivity. An allergy skin test can detect hypersensitivity to penicillin, but such tests are not available for other drugs.

Genetic tests of susceptibility are not available for most drugs, abacavir is one of the few. Screening does seem to be reliable and cost-efficient.^{1 2 3}

In some cases, starting with a low amount of drug and increasing slowly to the full dose can reduce the risk of drug-induced hypersensitivity. This type of desensitisation protocol is standard for nevirapine (Viramune) and may be used for patients who are sensitive to sulfonamide drugs and have no alternatives.

It is important that patients tell their healthcare providers about any hypersensitivity risk factors before starting a new medication. After starting a new drug, patients should report any adverse reactions or unusual symptoms immediately. Those taking drugs associated with higher rates of hypersensitivity, such as abacavir (Ziagen), should be educated about what types of symptoms to look for and be advised to seek emergency assistance if symptoms are life-threatening.

Patients taking drugs associated with hypersensitivity require careful and frequent monitoring, including assessment of symptoms and laboratory measurements such as liver function tests. Most hypersensitivity occurs within several weeks after starting a new drug and monitoring should happen more often during this period.¹