Tramadol hydrochloride--not just another opioid agonist

Tramadol and acetaminophen combination tablets in the treatment of fibromyalgia pain: a double-blind, randomized, placebo-controlled study

PURPOSE

To evaluate the efficacy and safety of a combination analgesic tablet (37.5 mg tramadol/325 mg acetaminophen) for the treatment of fibromyalgia pain.

METHODS

This 91-day, multicenter, double-blind, randomized, placebo-controlled study compared tramadol/acetaminophen combination tablets with placebo. The primary outcome variable was cumulative time to discontinuation (Kaplan-Meier analysis). Secondary measures at the end of the study included pain, pain relief, total tender points, myalgia, health status, and Fibromyalgia Impact Questionnaire scores.

RESULTS

Of the 315 subjects who were enrolled in the study, 313 (294 women [94%], mean [+/- SD] age, 50 +/- 10 years) completed at least one postrandomization efficacy assessment (tramadol/acetaminophen: n = 156; placebo: n = 157). Discontinuation of treatment for any reason was less common in those treated with tramadol/acetaminophen compared with placebo (48% vs. 62%, P = 0.004). Tramadol/acetaminophen-treated subjects also had significantly less pain at the end of the study (53 +/- 32 vs. 65 +/- 29 on a visual analog scale of 0 to 100, P <0.001), and better pain relief (1.7 +/- 1.4 vs. 0.8 +/- 1.3 on a scale of -1 to 4, P <0.001) and Fibromyalgia Impact Questionnaire scores (P = 0.008). Indexes of physical functioning, role-physical, body pain, health transition, and physical component summary all improved significantly in the tramadol/acetaminophen-treated subjects. Discontinuation due to adverse events occurred in 19% (n = 29) of tramadol/acetaminophen-treated subjects and 12% (n = 18) of placebo-treated subjects (P = 0.09). The mean dose of tramadol/acetaminophen was 4.0 +/- 1.8 tablets per day.

CONCLUSION

A tramadol/acetaminophen combination tablet was effective for the treatment of fibromyalgia pain without any serious adverse effects.

Newer analgesics. Nonsteroid anti-inflammatory drugs, opioids, and combinations

Analgesia is an intrinsic part of anesthesia, and the use of opioids for premedication, supplementation of anesthesia, and postoperative analgesia is not new. Development of new potent and less toxic NSAIDs has now resulted in this type of analgesic, also playing a major role in perioperative analgesia. Weak cyclo-oxygenase inhibitors, and NSAIDs with high COX2 activity, are proving successful in the provision of analgesia in dogs and cats. Some newer opioids developed for man have potential for use in dogs and cats, and buprenorphine, a partial agonist, deserves further evaluation. Some novel analgesics have potential for use in animals, but the specific analgesic role of old friends ketamine and the alpha 2 adrenoceptor agonists is worthy of closer scrutiny.