Pharmacological action:   

  Uses: penicillins are used for different types of bacteria (differ from penicillin group to another).

 

 Adverse effects: 

   Hypersensitivity (most important side effect of penicillins):

 Occur in about 5% of patients mainly due to the penicillins metabolite (penicilloic acid).

 This hypersensitivity is related to the basic structure of penicillin, so if patient has hypersensitivity from any penicillin, we predict that he has hypersensitivity from all groups of penicillins).

 Risk of hypersensitivity increased if patient has sensitivity to multiple allergens.

 

 Penicillin-hypersensitivity ranging from maculo-papular rash (most common with ampicillin) to angio-edema to anaphylaxis (less than 0.05 % of patients).

 Hypersensitivity may be mild and disappear even with continuing of penicillin. Also it may continue for 1-2 weeks or more after stopping therapy.

 Less of 1% of persons who previously received penicillin without incident will have an allergic reaction when given penicillin.