penicillins (general side-effects)

Last reviewed 02/2020

The principal side-effects of the penicillins are;

  • hypersensitivity resulting in urticaria, fever, joint pains and occasionally anaphylaxis. The hypersensitivity is related to the basic penicillin structure and therefore a patient hypersensitive to one penicillin will be hypersensitive to all. Note that it is important to clarify the history in penicillin hypersensitivity - the patient may have a different understanding of the word allergy to the physician.
  • encephalopathy which occurs with high doses or normal doses in people with renal failure. For this reason the penicillins cannot be given intrathecally.
  • diarrhoea with oral therapy especially with ampicillin and its derivatives which may also cause pseudomembranous colitis.