Pauls · Alzheimer's & dementia : the journal of the Alzheimer's Association 2022 · Randomized double-blind placebo-controlled crossover trial · n=55

The PASTIS trial: Testing tadalafil for possible use in vascular cognitive impairment.

Cited 43 times in the scientific literature.

Level 2 - randomized trial

Double-blind, placebo-controlled randomized crossover trial

PubMed 35135037 · doi:10.1002/alz.12559 · record verified 2026-08-31

What was done

Participants with symptomatic small vessel disease (mean age 66.8 ± 8.6 years) were enrolled in a double-blind, placebo-controlled crossover trial. Participants received tadalafil (20 mg) and placebo across two visits at least 7 days apart in randomized order. The primary endpoint was change in subcortical cerebral blood flow measured by arterial spin labelling.

What was found

Among 55 participants, tadalafil increased cerebral blood flow non-significantly across all subcortical areas, with the largest increase observed in white matter hyperintensities (+9.8%, P = .0960). Tadalafil significantly reduced systolic and diastolic blood pressure (-7.8 mmHg and -4.9 mmHg, respectively; P < .001). No serious adverse events were observed.

Why it matters

This trial provides early human evidence testing PDE5 inhibition for vascular cognitive impairment, finding that an acute single dose is insufficient to produce significant subcortical cerebral blood flow increases despite systemic blood pressure reduction.

Limits

The study assessed only a single 20 mg dose rather than chronic or repeated dosing schedules. The sample size was modest (N = 55), and cognitive or long-term clinical outcomes were not evaluated.

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