How effective is caffeine as an analgesic adjuvant for acute pain in adults?
Adding caffeine (at a dose equivalent to a mug of coffee, ie, about
100mg) to a standard dose of common analgesics, such as
paracetamol or ibuprofen, increased the number of people with
acute pain who experience a good level of pain relief (at least
50% of the maximum) by 5 to 10% (NNT* 15). The most common
conditions studied were postoperative dental pain, postpartum
pain, menstrual period pain and headache. One serious adverse
event was reported with caffeine but was considered unrelated to
any study medication.
*NNT = number needed to treat to benefit 1 individual.
Most comparisons individually demonstrated numerical superiority
with caffeine but not statistical superiority.
Caffeine is commonly used as a component in analgesics available
from pharmacies without a prescription in the belief that it
enhances analgesic efficacy.