Pharmacology of Analgesics: Clinical Considerations
Adjuvant Drugs to Enhance the Efficacy of Analgesics

Adjuvant drugs enhance the efficacy of analgesics or have analgesic activity of their own.⁵⁵ Caffeine in doses greater than 100 mg enhances the analgesic effect of NSAIDs and APAP. Hydroxyzine, a first generation antihistamine, in doses of 25 to 50 mg enhances the analgesic effect of opioids and reduces the incidence of opioid-induced nausea and vomiting. Corticosteroids, through their phospholipase-inhibitory effects, enhance analgesia in patients with pain of inflammatory origin.