Subjective, psychomotor, and analgesic effects of oral codeine and morphine in healthy volunteers

Abstract

The subjective, psychomotor, and physiological effects of analgesic doses of oral codeine and morphine were examined in 12 healthy volunteers. Subjects ingested placebo, morphine 20 or 40 mg, or codeine 60 or 120 mg in a randomized, double-blind, crossover design. The smaller and larger doses of each drug were putatively equianalgesic, and the cold-pressor test was included to test this assumption. Codeine and morphine increased ratings of "feel drug effect" but had little effect on other subjective measures, including the Addiction Research Center Inventory, visual analog scales, and adjective checklists. The few subjective effects that were observed were modest and were dose-related for morphine but not for codeine. The drugs did not affect performance on Maddox-Wing, digit-symbol substitution, coordination, auditory reaction, reasoning, and memory tests. Dose-related decreases in pupil size (miosis) were observed following codeine and morphine. Ratings of pain intensity decreased in a dose-related manner for morphine but not for codeine. Plasma codeine and morphine levels varied as an orderly function of dose. These results suggest that oral codeine and morphine are appropriate drugs for outpatient pain relief because they are effective analgesics at doses that have only modest effects on mood, produce few side effects, and do not impair performance. The results also suggest a possible ceiling effect of codeine on analgesia and subjective effects.

Attentional functioning in fibromyalgia, rheumatoid arthritis, and musculoskeletal pain patients

“…The RA and FM groups reported greater use of opioid medications compared with the MSK group. However, although a variety of medications, including opioids, are known to affect cognitive function, recent data have shown that attentional functioning is either not disrupted or improves in individuals, including chronic pain patients, following opioid consumption using both performance and electrophysiological measures (17)(18)(19)(20)(21)(22). In our study, patients who received opioid medications did not perform significantly differently from patients who did not receive opioids.…”

Cognitive and motor function after administration of hydrocodone bitartrate plus ibuprofen, ibuprofen alone, or placebo in healthy subjects with exercise-induced muscle damage: a randomized, repeated-dose, placebo-controlled study

“…Oral codeine has been associated with impaired handeye coordination in some investigations (Bradley and Nicholson 1986) but not others (Walker and Zacny 1998). When found, such deficits have been of small magnitude and short duration (Bradley and Nicholson, 1986).…”

Can Patients Receiving Opioid Maintenance Therapy Safely Drive? A Systematic Review of Epidemiological and Experimental Studies on Driving Ability With a Focus on Concomitant Methadone or Buprenorphine Administration

“…However, some experimental studies have not been able to demonstrate the impairing effects of opioids on either cognitive or psychomotor task performances of relevance to driving (Fishbain et al 2003;Hill and Zacny 2000;Walker and Zacny 1998;Zacny, Lichtor, Thapa, et al 1994). Likewise, some epidemiological studies have not been able to demonstrate an increased risk of traffic accident involvement (Drummer et al 2004;Ray et al 1993).…”