Treatments and drugs

By Mayo Clinic Staff

Interventions for a penicillin allergy can be divided into two general strategies:

  • Treatment for the present allergy symptoms
  • Desensitization to penicillin

Treating current symptoms

The following interventions may be used to treat the symptoms of an allergic reaction to penicillin:

  • Withdrawal of the drug. If your doctor determines that you have a penicillin allergy — or likely allergy — discontinuing the drug is the first step in treatment.
  • Antihistamines. Your doctor may prescribe an antihistamine or recommend an over-the-counter antihistamine such as diphenhydramine (Benadryl) that can block immune system chemicals activated during an allergic reaction.
  • Corticosteroids. Either oral or injected corticosteroids may be used to treat inflammation associated with more-serious reactions.
  • Treatment of anaphylaxis. Anaphylaxis requires an immediate epinephrine injection as well as hospital care to maintain blood pressure and support breathing.

Drug desensitization

If there are no other antibiotic treatment options available, your doctor may recommend a treatment called drug desensitization that would enable you to take a course of penicillin to treat an infection. With this treatment, you receive a very small dose and then progressively larger doses every 15 to 30 minutes over the course of several hours or a few days. If you can reach the desired dosage with no reaction, then you can continue the treatment.

You're carefully monitored during the intervention, and supportive care is available to treat reactions. Desensitization is rarely used if penicillin has caused a severe, life-threatening reaction in the past.

Nov. 22, 2014

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