['The introduction of phosphodiesterase-5 inhibitors as sildenafil, tadalafil, or vardenafil, has tremendously improved the treatment of erectile dysfunction. Patients with the common comorbidity of cardiovascular disease and erectile dysfunction, however, are at risk for critical hypotension in case of self-treatment of cardiac angina with nitrates after the intake of a phosphodiesterase-5 inhibitor.', 'We evaluated the safety of 5 mg sublingual nitrendipine after pre-treatment of 8 healthy male volunteers (42.1+/-9.6 yrs) with 20 mg tadalafil. Randomly four different protocols were compared using six hours blood pressure recordings: (1) baseline, (2) 20 mg tadalafil, (3) 5 mg nitrendipine, and (4) 20 mg tadalafil+5 mg nitrendipine.', 'The blood pressure was not significantly affected by tadalafil. Nitrendipine lowered the systolic blood pressure significantly by -1.91 mmHg (p=0.0079). The co-medication of 20 mg tadalafil+5 mg nitrendipine lowered the blood pressure significantly by -2.86 mmHg (p<0.0001). There was no statistically significant difference between tadalafil and nitrendipine (p=0.598). Relevant hypotension (systolic blood pressure of <85 mmHg) was observed in none of the study individuals during the four protocols.'] Does sublingual application of liquid nitrendipine result in critical hypotension in healthy volunteers under phosphodiesterase-5 inhibition?