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Effects of methyldopa on psychometric performance

B Johnson1, K Hoch, A Errichetti

  • 1Division of Clinical Pharmacology, University of Massachusetts Medical Center, Worcester 01655.

Journal of Clinical Pharmacology
|December 1, 1990
PubMed

Insights

Methyldopa, an antihypertensive drug, reduced blood pressure but impaired cognitive function in patients. Practice effects confounded results, highlighting limitations in simple crossover study designs for assessing drug impacts on cognition.

Area of Science:

  • Pharmacology
  • Neuroscience
  • Clinical Trials

Background:

  • Hypertension management often involves medications with potential cognitive side effects.
  • Assessing the cognitive impact of antihypertensive drugs requires rigorous study designs.

Purpose of the Study:

  • To evaluate the cognitive effects of methyldopa in patients with mild to moderate hypertension.
  • To compare the efficacy of methyldopa against a placebo in a controlled setting.

Main Methods:

  • A double-blind, crossover study involving 16 hypertensive patients.
  • Patients received methyldopa (250 mg three times daily) or placebo for 14 days.
  • Cognitive performance was assessed using psychometric tests, including card sorting and digital symbol substitution.

Main Results:

  • Methyldopa significantly reduced blood pressure compared to placebo.
  • Methyldopa treatment led to impairments in card-sorting time and digital symbol substitution scores.
  • Practice effects on cognitive tests were substantial and, in most cases, greater than treatment effects.

Conclusions:

  • While methyldopa effectively lowers blood pressure, it can negatively impact cognitive performance.
  • Practice effects represent a significant confounder in crossover studies assessing drug-induced cognitive changes.
  • Simple crossover designs may be insufficient to detect moderate cognitive effects of medications.

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