(276) - Does opioid-induced nausea and vomiting (OINV) interfere with pain control?

Abstract

Nausea and vomiting are distressing symptoms. Among other emetogenic medications, opioids are well-known pharmacologic causes of nausea and vomiting (i.e., OINV). Common sense suggests that OINV would interfere with pain control. Does it? What effect does OINV have on pain relief when patients are treated with a standard opioid-containing medication such as hydrocodone 7.5 mg/acetaminophen 325 mg (HC/APAP)? We had the opportunity to address this question in a randomized, double-blind, placebo-controlled trial by comparing pain reduction in patients treated with HC/APAP who developed OINV to pain reduction in patients treated with HC/APAP who did not. After unilateral first metatarsal bunionectomy with osteotomy and internal fixation without collateral procedures, adult patients were randomized under double-blind conditions to HC/APAP or placebo when they reported moderate-to-severe pain on a 0–10 numerical pain intensity rating scale. At specified intervals over the initial 48-hour post-op treatment observation period they rated the intensity of pain and nausea and documented episodes of vomiting and uses of antiemetics while taking study medication every 4–6 hours. Summed pain intensity differences were calculated over 48 hours (SPID48), in particular, to determine pain reduction in HC/APAP-treated patients with and without OINV. There were no significant clinical or demographic differences at baseline among 300 patients who were randomized to HC/APAP or placebo. OINV occurred in 45% of HC/APAP-treated patients. Mean SPID48 scores significantly differentiated HC/APAP treatment from placebo for all patients, for patients with OINV, and for patients without OINV. Mean SPID48 scores were approximately 40% lower for HC/APAP-treated patients who had OINV than for HC/APAP-treated patients who did not have OINV (P < .001). This study demonstrates that a commonly used opioid medication is significantly less effective as an analgesic for patients with OINV than patients without OINV. We conclude that OINV interferes with pain relief. Sponsored by Charleston Laboratories, Inc.