Effects of the non-selective phosphodiesterase inhibitor pentoxifylline on regional cerebral blood flow and large arteries in healthy subjects

The vasodilating properties of the non‐selective phosphodiesterase (PDE) inhibitor pentoxifylline were evaluated. Pentoxifylline has been reported to increase cerebral blood flow (CBF) and improve recovery rate of stroke patients. Whether these results are due to a dilating effect on arteries or to other mechanisms is not clear. In the present double‐blind crossover study, 10 healthy subjects received pentoxifylline 300 mg or placebo intravenously on separate days. Blood flow velocity in the middle cerebral artery (Vmca) was recorded by transcranial Doppler and rCBF was measured using 133Xenon‐inhalation SPECT. High‐frequency ultrasound was used for measurements of temporal and radial artery diameter. Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) concentrations were assessed in plasma. Except for increased heart rate (P