side effect [AS, side + L, effectus] , any reaction to or consequence of a medication or therapy. This can be an effect carried beyond the desired limit, such as hemorrhaging from an anticoagulant, or a reaction unrelated to the primary object of the therapy, such as an anaphylactic reaction to an antibiotic. Usually, although not necessarily, the effect is undesirable and may manifest itself as nausea, dry mouth, dizziness, blood dyscrasias, blurred vision, discolored urine, or tinnitus.
