Caffeine as an analgesic adjuvant
E. M. Laska, A. Sunshine, F. Mueller, W. B. Elvers, C. Siegel and A. Rubin
Thirty clinical studies involving more than 10,000 patients conducted
during the last 20 years have been analyzed to assess the value of caffeine
as an analgesic adjuvant. Although most studies included patients with
postpartum uterine cramping or episiotomy pain, some involved patients with
pain from oral surgery or headache. In 21 of 26 studies, the relative
potency estimates of an analgesic with caffeine to an analgesic without
caffeine is greater than one. The pooled relative potency estimates in each
of several major categories of combination analgesics are significantly
greater than one. The overall pooled relative potency estimate is 1.41,
with 95% confidence limits of 1.23 to 1.63; that is, to obtain the same
amount of response from an analgesic without caffeine requires a dose that
is approximately 40% greater than one with caffeine.
