The antinociceptive efficacy of morphine-ketamine-magnesium combination is influenced by the order of medication administration.

OBJECTIVE: Ketamine and magnesium, both N-methyl-D-aspartate (NMDA) receptor antagonists, enhance the antinociceptive effects of opioid analgesics in different animal models of pain, as well as in humans. This study aimed at evaluating whether magnesium sulphate added to morphine-ketamine combination produces a higher level of analgesia. MATERIALS AND METHODS: Analgesic activity was assessed by tail-immersion test in male Wistar rats (200-250 g). RESULTS: Magnesium sulphate (0.5-60 mg/kg, s.c.) and ketamine (5-30 mg/kg, i.p.) administered alone did not produce any effect. Magnesium sulphate (5 and 60 mg/kg) and ketamine (5 and 30 mg/kg) increased the antinociceptive effect of morphine (2.6 mg/kg, i.p.). Magnesium sulphate (5 mg/kg) increased the antinociceptive effect of the morphine (2.6 mg/kg)-ketamine (2.5 or 5 mg/kg) combination when magnesium sulphate was added to morphine after, and not before ketamine. It is also demonstrated that magnesium sulphate prolonged the duration of the antinociceptive effect of the morphine-ketamine combination. Low dose of morphine (2.6 mg/kg), ketamine (5 mg/kg) and magnesium sulfate (5 mg/kg) given together did not cause motor impairment that could be verified on a rotarod test. The antinociceptive effect of the triple combination was readily antagonized with naloxone (3 mg/kg, s.c.), a nonselective antagonist of opioid receptors, indicating that the effect is mediated via opioid receptors. CONCLUSIONS: This study revealed that the efficacy of the morphine-ketamine-magnesium sulphate combination in tail-immersion test in rats is influenced by the order of medication administration; a higher level of activity is demonstrated only when ketamine is added to morphine before magnesium sulphate.

[Complications on skin and subcutaneous tissue among drug addicts caused by non sterile intra venous injections and burns].

The use of psychoactive substances causes various consequences and is harmful for all organs. Some of the health consequences among intravenous drug users are HIV infections, hepatitis C, local tissue infections after drug injection, family, professional and social consequences. Throught the world various harm reduction programs are established in order to educate drug users about safer drug injecting techniques, with the use of sterile needles and materials for disinfection of the drug injecting area. Authors presented epidemiological data, consequences on extremities after non sterile drug injecting and accidental burns, harm reduction programs as well as other guidelines in this field. In three case reports of intravenous drug addicts with surgical complications on the extremities and burns, surgical and anaesthesiological approaches were described. Special emphasis was given to preoperative preparations and the postoperative treatment as well as social-psychiatric aspect.