TREATMENT WITH ENALAPRIL MODIFIES THE PAIN PERCEPTION PATTERN IN HYPERTENSIVE PATIENTS

The cardiovascular system shares numerous anatomic and functional path ways with the antinociceptive network. The aim of this study was to in vestigate whether angiotensin-converting enzyme (ACE) inhibitor treatm ent could affect hypertension-related hypalgesia, Twenty-five untreate d hypertensive patients, together with a control group of 14 normotens ive subjects, underwent dental pain perception evaluation by means of a pulpar test (graded increase of test current applied to healthy teet h). After the evaluation of the dental pain threshold (occurrence of p ulp sensation) and tolerance (time when the subjects asked for the tes t to be stopped), all the subjects underwent a 24-hour ambulatory bloo d pressure monitoring. The hypertensive group then was treated with 20 mg/d enalapril, whereas the normotensive subjects remained without an y treatment. After a time interval of 6+/-2 months, the dental pain se nsitivity was retested in all the subjects, and ambulatory blood press ure was recorded during treatment in the hypertensive patients. At the first assessment, hypertensive patients showed a higher pain threshol d than normotensive subjects (P<.001). On retesting of pain sensitivit y in hypertensive patients, a significant decrease of both pain thresh old and tolerance, leading to their normalization, was observed during treatment (P<.001 and P<.005, respectively), in the presence of reduc ed 24-hour and office blood pressure values. A slight, though signific ant, correlation was observed between variations in pain tolerance and baseline blood pressure changes occurring during treatment. During fo llow-up, the normotensive subjects did not show any significant pain p erception or office blood pressure changes. Hypertension-related hypal gesia was confirmed. Mechanisms acting both through lowering of blood pressure and specific pharmacodynamic properties may account for the n ormalization of pain sensitivity observed in hypertensive patients dur ing treatment with ACE inhibitors.