Dictionary of Evidence-based Medicine.pdf

Dictionary of Evidence-based Medicine 155
relevant health authority. This activity is being transferred to primary care
groups (DoH (1997) The new NHS. Cmd 3807. HMSO, London).
Treatment guidelines (see under Practice guidelines)
Treatment received analysis (see Intention to treat analysis)
True negative ratio (see Specificity)
True positive ratio (see Sensitivity)
Type A adverse reaction
A type A (augmented effect) adverse drug reaction is one which is predictable
from the pharmacology of the drug (e.g. hypotension caused by
antihypertensive drugs and anticholinergic adverse effects of Hj antihistamines).
Such adverse reactions can usually be managed through appropriate
dose titration. In theory, everyone is susceptible to type A reactions
if the offending drug dose is increased sufficiently (Park K, Pirmohamed
M, Kitteringham NR (1992) Idiosyncratic drug reactions: a mechanistic
evaluation of risk factors. British Journal of Clinical Pharmacology and Therapeutics.
34: 377-95).
Type B adverse reaction
A type B (bizarre) reaction is one which is idiosyncratic and usually appears
to be independent of both dose and pharmacology of the drug. It
is difficult to predict and is often serious. Examples are penicillin allergy
and blood dyscrasias associated with some drugs (Park K, Pirmohamed M,
Kitteringham NR (1992) Idiosyncratic drug reactions: a mechanistic evaluation
of risk factors. British Journal of Clinical Pharmacology and Therapeutics.
34: 377-95).
Type C adverse reaction
A type C adverse reaction is one associated with long-term therapy.
Although the mechanism may be unclear, because such reactions (e.g.
benzodiazepine dependence) are well described and are characteristic of