Anaphylactic (Anaphylactoid) Reaction
A group of symptoms which
represent (or resemble) a sometimes
overwhelming and
dangerous allergic reaction due to
extreme hypersensitivity to a drug. Anaphylactic reactions, whether
mild,
moderate, or
severe, often involve several
body systems. Mild symptoms consist of
itching,
hives,
nasal congestion,
nausea,
abdominal cramping and/or
diarrhea. Sometimes these precede more severe symptoms such as choking,
shortness of breath, and sudden loss of
consciousness (usually referred to as
anaphylactic shock).
Characteristic features of
anaphylactic reaction must be kept in mind. It can result from a
very small dose of drug; it can be rapidly progressive and can lead to
fatal collapse in a short time if not reversed by
appropriate treatment. A developing
anaphylactic reaction is a true
medical emergency. Any adverse effect that appears withing 20 minutes after taking a drug should be considered the early
manifestation of a possible
anaphylactic reaction.
Obtain medical attention immediately.
--From The Essential Guide to Prescription Drugs