Studies of Plasma Quinidine Content
II. Relation to Toxic Manifestations and Therapeutic Effect
The gastrointestinal symptoms of quinidine toxicity occurred without relation to plasma concentration, suggesting that most examples are due to individual local gastrointestinal sensitivity and some, associated with giddiness, occur only at higher levels and may be due to nervous system effects. Tinnitus, visual disturbances and marked hypotension generally occurred at relatively high plasma quinidine concentrations. It is suggested that hypotension is due to a nervous system effect rather than to myocardial incompetence, but nonetheless warrants cessation of administration.
- © 1950 American Heart Association, Inc.