Pyridostigmine in the treatment of orthostatic intolerance.
OBJECTIVE
To review the efficacy of pyridostigmine bromide for the treatment of orthostatic intolerance.


METHODS
MEDLINE and International Pharmaceutical Abstracts were searched (1966-December 2006) using the terms pyridostigmine, acetylcholinesterase inhibitor, orthostatic intolerance, orthostatic hypotension, neurogenic orthostatic hypotension, postural tachycardia syndrome, tachycardia, and orthostatic tachycardia.


METHODS
Pertinent English-language human clinical trials, case reports, and background material were evaluated for safety and efficacy data. The references of reviewed articles were reviewed and used to identify additional sources.


RESULTS
Pyridostigmine bromide has been associated with improved baroreceptor sensitivity and presents a novel approach to treatment of orthostatic intolerance. Four single-dose trials and a follow-up survey encompassing a total of 106 patients were identified. One open-label and one placebo-controlled single-dose trial in patients with neurogenic orthostatic hypotension (NOH) found statistically significant improvement in standing diastolic blood pressures (DBP). Absolute improvements in standing DBP were 3.7 and 6.4 mm Hg in the open-label and controlled trials, respectively. Long-term data consist of a single survey of patients receiving open-label pyridostigmine bromide. Twenty-nine percent of patients who initiated maintenance pyridostigmine bromide discontinued therapy. Concomitant NOH medications were taken by 75% of patients, and 85% of patients reported receiving benefit from pyridostigmine bromide. When evaluated for postural tachycardia syndrome, pyridostigmine bromide significantly reduced standing heart rate (10%). Pyridostigmine bromide significantly reduced symptom scores when compared with baseline but not placebo. The majority of patients included in these trials did not have supine hypertension.


CONCLUSIONS
Single doses of pyridostigmine bromide produced modest but statistically significant improvements in hemodynamic measurements. At this time, long-term data are insufficient to support recommending the routine use of pyridostigmine bromide for treatment of orthostatic intolerance.
Gales
Barry J
BJ
Department of Pharmacy Practice, College of Pharmacy, Southwestern Oklahoma State University, Oklahoma City, OK, USA. barry.gales@swosu.edu
Gales
Mark A
MA
D001342:Autonomic Nervous System Diseases / Q000188:drug therapy*; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D006801:Humans; D007024:Hypotension, Orthostatic / Q000188:drug therapy*; D011729:Pyridostigmine Bromide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D013610:Tachycardia / Q000188:drug therapy*; D016896:Treatment Outcome
D002800:Cholinesterase Inhibitors; D011729:Pyridostigmine Bromide