Opposite changes in blood pressure and pulse rate in two patients with distigmine and rivastigmine intoxication.

Background: Cholinergic crisis caused by cholinesterase inhibitors is rare but life-threatening. Clinical manifestations are thought to be similar to those caused by organophosphates.

Case Presentation: A 77-year-old woman on a standard dose of distigmine presented with impaired consciousness, blood pressure (BP) of 69/40 mmHg, a pulse rate (PR) of 60 beats/min, miosis, bronchorrhea, and serum cholinesterase (ChE) of 8 IU/L. After discontinuation of distigmine, altered mental status and pupil miosis were gradually resolved in 5 days with a concomitant increase of serum ChE. A 91-year-old woman presented with a headache, BP of 202/86 mmHg, PR of 83 beats/min, miosis, 9 rivastigmine patches on her knees, and ChE of 22 IU/L. The day after close observation without rivastigmine use, her symptoms were almost resolved with a concomitant increase of serum ChE.

Conclusion: Our cases and a literature review suggested that, in contrast to distigmine, rivastigmine-induced cholinergic crisis caused hypertension and tachycardia.