Abstract
We observed a patient at 33 weeks' gestation who was administered exceptionally large doses of quinidine to treat a fetal supraventricular tachycardia. The patient had clinical evidence of quinidine toxicity at low to mid-therapeutic levels of quinidine, but markedly elevated levels of the metabolite 3(S)-3-hydroxyquinidine (3-hydroxyquinidine). This pattern is consistent with a 'fast metabolism' of quinidine. There is substantial evidence that 3-hydroxyquinidine has pharmacologic activity. We conclude that elevated levels of 3-hydroxyquinidine can be associated with a clinically significant quinidine toxicity. This can occur in the presence of a nontoxic serum quinidine level. We also measured the levels of quinidine and 3-hydroxyquinidine in the amniotic fluid and cord blood. The levels in the cord blood were 31 and 27%, respectively, of those in a simultaneously drawn maternal blood sample.
Original language | English (US) |
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Pages (from-to) | 445-449 |
Number of pages | 5 |
Journal | Obstetrics and gynecology |
Volume | 70 |
Issue number | 3 PART II |
State | Published - 1987 |