Effects of cimetidine in control of post operative pain

Pain is the most common complaint of patients and therefore its treatment is the most ancient problem of human being. Since opioids have many side effects, morphine (MOR) are administrated limitedly. Recent studies have shown that cimetidine (CIM) induces analgesia in animals and humans. This study was designed to evaluate the effect of CIM in control of post operative pain. This study was a double-blind clinical trial. Following filling a consent form, one hundred and twenty patients (male & female) were randomly divided to four groups. The first three groups, as CIM groups, were received different doses of CIM (3mg /kg, 6mg /kg and 8mg /kg) and the last group given MOR (o.1 mg/kg). The drugs were injected (IV) in peak of pain during post operation period. Numeric rating pain scale (RPS) method was used for pain scaling. Pain was measured in 30 min, 60 min and 120 min after injection the drug and compared with pain score before injection of the drug. Pain intensity was not significantly different prior to injection, 30, 60 min and 120 min after drug injections in all four groups (MOR and CIM groups), but it was significantly lower when compared with pain score before injection of drug (P< 0.05). In addition, there were no significant differences in duration of analgesia among four groups. The results of this study indicated that the analgesic effects (time and quality) of CIM (each three doses) are compatible with that those induced by MOR. Therefore, It seems that CIM is a safe drug in control of post operative pain.