Objective
The aim was to test the effect of amantadine, an NMDA antagonist, on tourniquet induced cardiovascular responses under general anesthesia.
Method
In a randomized, double blind, placebo-controlled study; thirty adult male patients with ASA physical status I or II, aged 18–50 years underwent anterior cruciate ligament reconstruction with a tourniquet under general anesthesia, were divided to receive either oral amantadine 200 mg capsule in the evening before surgery and 200 mg capsule 60 min before surgery (group A) or placebo capsules (group P). Heart rate, systolic and diastolic blood pressures were recorded (before induction of anesthesia, every 15 min after tourniquet inflation, before tourniquet deflation, and 10 min after tourniquet deflation). Incidence of tourniquet-induced hypertension, and postoperative tramadol consumption were also recorded.
Results
Systolic and diastolic pressures significantly increased in both groups compared to baseline values ( < 0.05) at 15, 30, 45, 60, 75 min after tourniquet inflation, and before tourniquet deflation with significantly lesser increase with amantadine compared to placebo at 45, 60, and 75 min after tourniquet inflation ( < 0.05). Heart rate significantly increased at 45, 60, and 75 min after tourniquet inflation in both groups compared to baseline values ( < 0.05) with significantly lesser increase with amantadine compared to placebo ( < 0.05). Development of tourniquet induced hypertension was less with amantadine (5 out of 15) than with placebo (8 out of 15).The total tramadol consumed during the first 24 h postoperative was significantly less with amantadine compared to placebo ( < 0.05).
Conclusion
Preoperative oral amantadine reduced tourniquet induced hypertension and postoperative analgesic requirements in anterior cruciate ligament reconstruction surgery under general anesthesia.