Efficacy of analgesics in chronic pain: a series of N-of-1 studies

J Pain Symptom Manage. 1998 Apr;15(4):244-52. doi: 10.1016/s0885-3924(98)00369-8.


Rational drug treatment of chronic musculoskeletal pain remains a challenge. Although commonly prescribed, the true efficacy of opioid analgesics or of nonsteroidal antiinflammatory drugs remains to be established. Using an N-of 1 design, eight patients with regional cervicobrachial pain received ibuprofen 800 mg/day, codeine 120 mg/day, or placebo during six 2 week periods. Clinical outcomes were assessed by pain diary, VAS of pain and change in pain, and uptime/downtime estimates. In none of the five subjects who completed the 12-week trial was analgesic efficacy of either drug shown. Major psychosocial and other medical influences on the subjects' status were encountered. The N-of 1 methodology is appropriated for evaluating true efficacy of pharmacotherapy in patients with regional musculoskeletal pain.

Publication types

  • Case Reports
  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Analgesics, Opioid / therapeutic use*
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Chronic Disease
  • Codeine / therapeutic use*
  • Female
  • Humans
  • Ibuprofen / therapeutic use*
  • Male
  • Middle Aged
  • Pain / drug therapy*


  • Analgesics, Opioid
  • Anti-Inflammatory Agents, Non-Steroidal
  • Codeine
  • Ibuprofen