B-vitamin mixture improves the analgesic effect of diclofenac in patients with osteoarthritis: a double blind study

Drug Res (Stuttg). 2013 Jun;63(6):289-92. doi: 10.1055/s-0033-1334963. Epub 2013 Mar 22.


According to the high consumption of the mixture of B vitamins and diclofenac in several countries, this combination has constituted a frequently used option in pain therapy from inflammatory origin. Although the evidence obtained from inflammatory pain animal models has shown the existence of analgesic synergy between diclofenac and the B vitamins mixture, the corresponding clinical evidence is scarce. A double-blind, randomized clinical trial study was designed to characterize the analgesic effect and safety of diclofenac and B vitamins against diclofenac alone in patients with severe osteoarthritis. Forty eight patients programmed to total knee arthroplasty with a pain level ≥7 in a 1-10 cm visual analogue scale were allocated to receive a single intramuscular injection of sodium diclofenac (75 mg) alone or combined with thiamine (100 mg), pyridoxine (100 mg) and cyanocobalamin (5 mg), and the pain level was evaluated during 12 h post-injection. Diclofenac+B vitamins mixture showed a superior analgesic effect during the assessed period and also a better assessment of the pain relief perception by patients than diclofenac alone. This study constitutes a clinical support on the improvement of the analgesic effect of diclofenac by B vitamins in patients with osteoarthritis programmed to total knee arthroplasty, as a clinical model of inflammatory pain.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Analgesics / pharmacology*
  • Diclofenac / adverse effects
  • Diclofenac / pharmacology*
  • Double-Blind Method
  • Drug Synergism
  • Female
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis / drug therapy*
  • Vitamin B Complex / pharmacology*


  • Analgesics
  • Vitamin B Complex
  • Diclofenac