Adjuvant analgesics are usually considered when the patient with cancer pain fails to attain a satisfactory balance between analgesia and side effects during opioid therapy, or experiences a comorbid symptom or disorder that may be amenable to one of the adjuvant drugs. When pain is the primary indication, the use of adjuvant analgesics is one strategy that must be evaluated in comparison with other potentially analgesic approaches. The potential costs, inconvenience, and risks associated with polypharmacy must be balanced by demonstrable benefits. To offer the most informed recommendation, the clinician must have a strong working knowledge of the many drugs currently used as adjuvant analgesics and a detailed assessment of the patient and pain syndrome.