Type A reaction

Type B reaction

Predictable

Unpredictable

Common, rational

less common, bizarre, not rational

Related to drug pharmacologic actions

Related to individual susceptibility.

Dose dependent

Not dose dependent

Examples:

・ Toxicity: renal failure from aminoglycosides.

・ Side effect: sedation from antihistamines.

・ Secondary effect: diarrhea from antibiotics.

・ Drug-drug Interaction: theophylline toxicity from concomitant erythromycin

Examples:

・ Intolerance: tinnitus from Aspirin

・ Idiosyncratic reaction: hemolysis from Dapsone in G6PD deficiency.

・ DHR: anaphylaxis from penicillin.

・ Pseudo allergic anaphylaxis due to radio contrast media.