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At least 19 recordsLinked to original sources

Interactions of codeine-7,8-oxide (codeine-epoxide), as a new metabolite of codeine, with multiple opiate receptors.

Interactions of codeine-epoxide, a new metabolite of codeine, with multiple opiate receptors were studied using radioligand binding assay. The ability of codeine-epoxide to displace [3H]dihydromorphine binding was the most effective among three labeled ligands, that is, [3H]dihydromorphine, [3H]-D-Ala2-D-Leu5-enkephalin and [3H]ethylketocyclazocine, suggesting that codeine-epoxide had a selectively high affinity to mu-receptors, despite the fact the affinities of codeine-epoxide to opiate receptors were slightly less potent than its parent compound, codeine. Since "sodium ratio" and "GTP ratio" on codeine-epoxide binding lay between those of codeine and naloxone, the interaction of codeine-epoxide with opiate receptors may be slightly different from that of codeine.

Animals↗

Human pharmacokinetic study of immediate-release (codeine phosphate) and sustained-release (codeine Contin) codeine.

The authors compared, in a double-blind, randomized, crossover study in 13 healthy adult volunteers, the single- and multiple-dose pharmacokinetics, relative bioavailability, and side effects of a new oral sustained-release formulation of codeine (SRC) containing 150 mg codeine base, with oral immediate-release codeine phosphate (IRC). Sustained-release codeine was given at a dose of 150 mg every 12 hours for 5 doses; IRC was given at a dose of 60 mg (2 x 30 mg) every 4 hours for the first 3 doses, and 30 mg every 4 hours thereafter for 12 doses. Plasma codeine levels were determined using a sensitive and specific high-performance liquid chromatography method and corrected for dose administered and codeine base equivalent. Mean values for single-dose pharmacokinetic parameters for SRC and IRC, respectively, were: Cmax of 217.8 and 138.8 ng/mL; Tmax of 2.3 and 1.1 hours; AUC0-inf of 1202.3 and 1262.4 ng.mL-1.hour-1; and t1/2el of 2.6 hours for both formulations. Their respective mean steady-state pharmacokinetic parameters were: Cmax of 263.8 and 222.9 ng/mL; Tmax of 3.2 and 1.1 hours; AUC0-12h of 1576.4 and 1379.1 ng.mL-1.hour-1; and t1/2el of 2.8 and 2.3 hours. These results indicate comparable bioavailability between both formulations with SRC providing delayed peak plasma levels. The sustained-release character of SRC can be explained by a delayed absorption, which is not limiting to drug elimination. Sustained-release codeine provides higher plasma codeine levels over a broader time interval and is expected to improve pain management.

Adult↗

Pharmacogenetic determinants of codeine induction by rifampin: the impact on codeine's respiratory, psychomotor and miotic effects.

Our objective was to examine the effect of rifampin on codeine's pharmacodynamics and pharmacokinetics in extensive (EMs) and poor (PMs) metabolizers of debrisoquin. Fifteen healthy, nonsmoking males, 9 EMs and 6 PMs of debrisoquin, received codeine (120 mg) before and after rifampin (600 mg/d) for 3 weeks. The effects of codeine on respiration, pupil diameter and psychomotor performance were measured before codeine administration and during each study day. The pharmacokinetics of codeine were determined from the respective plasma and urine concentrations. Before the administration of rifampin, the pharmacodynamic effects of codeine were more prominent in the EMs (P < .01). Rifampin significantly enhanced codeine oral clearance by increasing its metabolic clearances through N-demethylation and glucuronidation in both phenotypes, but its O-demethylation was induced only in EMs. Relative to base-line values, codeine N-demethylation was induced to a greater extent, resulting in a marked reduction in the plasma concentrations of codeine and codeine metabolites and elevated plasma concentrations of norcodeine, norcodeine-glucuronide, and normorphine. The reduction in morphine plasma concentration was associated in the EMs with a significant attenuation of codeine's respiratory and psychomotor effects, whereas its miotic effect was unaltered. In PMs, codeine's respiratory and psychomotor effects were unaltered by rifampin, but its pupillary effect was reduced. Codeine O-demethylation to produce morphine can be significantly induced by rifampin, but this induction is phenotypically determined. However, because (relative to base-line values) rifampin enhanced codeine N-demethylation more than codeine O-demethylation, morphine plasma concentrations were reduced-and hence codeine's pharmacodynamic effects were attenuated-in EMs of debrisoquin.

Adult↗

Analgesic effect and plasma concentrations of codeine and morphine after two dose levels of codeine following oral surgery.

A double blind randomised cross over investigation was carried out in 25 male patients undergoing two oral surgical extractions, one for each lower wisdom tooth. The two extractions were performed about 6 weeks apart and were carried out under local anaesthesia. One hour after each extraction the patients randomly received 90 or 45 mg codeine. During the following 5 h the patients rated the intensity of their pain on a visual analogue scale. Blood was simultaneously sampled and assayed for codeine and its metabolite morphine. Mean pain intensity difference was just significantly higher after 90 mg codeine compared to 45 mg. The mean plasma concentrations of codeine and morphine were significantly higher after the 90 mg dose. However, for the two dose levels of codeine there was no obvious relationship between the difference in analgesic effect and the difference in the plasma concentration of codeine or morphine. The plasma concentrations of morphine were 2-3% of those of codeine and the levels were relatively low. Local formation of morphine from codeine within the human brain should therefore be investigated. Four patients were unable to demethylate codeine to a detectable plasma concentration of morphine after 90 mg codeine. In those patients the analgesic effect during the first hours was better after 90 mg codeine than after 45 mg. This suggests some analgesic effect of codeine itself.

Administration, Oral↗

Correlation of saliva codeine concentrations with plasma concentrations after oral codeine administration.

A clinical study was designed to determine if there was a predictable relationship between saliva and plasma codeine concentrations. Drug-free volunteers (n = 17) were administered a 30-mg dose of liquid codeine phosphate. Plasma and saliva specimens were collected at various times for 24 h after administration. Plasma and saliva were analyzed for codeine and morphine by positive-ion chemical ionization gas chromatography-mass spectrometry. The plasma codeine concentrations peaked between 30 min and 2 h after administration and ranged from 19 to 74 ng/mL with a mean of 46 ng/mL. Despite decontamination procedures, elevated saliva codeine concentrations were detected at the early collection times because of contamination of the oral cavity from the liquid codeine. Codeine concentrations in the 15 min specimens ranged from 690 ng/mL to over 15,000 ng/mL. After the initial 2-h period, the mean codeine saliva concentrations declined at a rate similar to that observed in the plasma, but remained 3 to 4 times greater than the plasma concentrations. During the elimination phase, half-life estimates for codeine in plasma and saliva were found to be equivalent, 2.6 and 2.9 h, respectively. However, the area under the curve (AUC) estimate for codeine in saliva was 13 times greater than the plasma AUC. Contamination of the saliva resulted in elevated saliva/plasma (S/P) concentration ratios for the first 1 to 2 h after drug administration. Consequently, S/P ratios in specimens collected in the first 15 to 30 min ranged from 75 to 2580. However, after the absorption phase, a significant correlation between saliva and plasma concentrations was observed (r = 0.809, p < 0.05) and mean S/P ratios remained constant (mean = 3.7). Although small changes in saliva pH were predicted to produce profound changes in the S/P ratios for codeine, this was not observed in the current study. Therefore, saliva codeine concentrations could be used to estimate plasma concentrations through the use of the S/P ratio once the oral contamination has been eliminated. However, these estimates should be made cautiously. One must ensure that oral contamination is not a factor. Also, as with blood-drug concentrations, considerable intersubject variability was observed.

Administration, Oral↗

Plasma codeine and morphine concentrations after therapeutic oral doses of codeine-containing analgesics.

Plasma concentrations of codeine and morphine were determined by specific radioimmunoassays in healthy human subjects at various times following oral administration of analgesic preparations containing therapeutic doses of codeine phosphate. Following administration of codeine phosphate (60 mg) in combination with aspirin (650 mg) or acetaminophen (600 mg) to two separate groups, mean peak codeine plasma concentrations and beta-phase elimination half-lives were 159 ng/ml and 2.9 hr or 138 ng/ml and 2.4 hr, respectively. Mean maximum concentrations of metabolically produced morphine were 6.8 ng/ml (aspirin-codeine phosphate administration) and 7.4 ng/ml (acetaminophen-codeine phosphate). Following drug administration, the mean ratio of the areas under the respective plasma concentration-time curves for morphine and codeine was 0.095 for the aspirin-codeine phosphate study and 0.12 for the acetaminophen-codeine phosphate study. Thus, free morphine represented about 10% of the free codeine area in each case. These results support the hypothesis that metabolically produced morphine may influence or be responsible for the analgesic efficacy of codeine.

Acetaminophen↗

Urinary concentrations of codeine and morphine after the administration of different codeine preparations in relation to doping analysis.

A capillary GC method with nitrogen-specific detection is described for the analysis of codeine and morphine in urine. Both drugs were determined after enzymatic hydrolysis of the urine. Morphine was derivatized with trifluoroacetic anhydride. For 5-ml samples of urine, the lower detection limits for accurate quantitation were 50 ng ml-1 and 100 ng ml-1 for morphine and codeine, respectively. Both codeine and morphine were already detectable in urine 1 h after the intake of the analgesic preparation Perdolan. Codeine excretion and concentration peaked 2 h after administration of a dose. The percentage of the dose excreted as codeine was 3.0-6.2%. Administration of the antitussive preparation Bisolvon Griblettes resulted in detectable codeine and morphine levels for at least one day; 5.6-9% was excreted as total codeine over 24 h, the conjugated metabolite morphine accounting for 1.7-7.4% of the dose. Nearly the same amounts of codeine and morphine were excreted after administration of the antitussive syrup Bronchodine. The maximum excretion rate of codeine occurred after 1 h. Generally codeine and morphine remained detectable for 12 h. The results of these administration studies are discussed in relation to the codeine and morphine threshold levels recently introduced by the International Cyclist Union.

Chromatography, Gas↗

The dose-response relationship of controlled-release codeine (Codeine Contin) in chronic cancer pain.

The improved pain control provided by regular dosing of opioid analgesics in patients with severe cancer pain has been well established. However, the treatment of mild-to-moderate cancer pain is often limited to "as needed" dosing with fixed combinations of codeine or oxycodone plus a nonopioid analgesic, which do not allow optimal titration of the individual components. This randomized double-blind study was designed to evaluate the efficacy of controlled-release codeine (Codeine Contin) in patients with cancer pain, and to estimate its dose equivalence to a standard combination of acetaminophen plus codeine. Twenty-four patients with at least moderate cancer pain were randomized to Codeine Contin 100, 200, or 300 mg every 12 hr or acetaminophen plus codeine (600 mg/60 mg) every 6 hr. On days 1 and 4 of dosing, pain intensity and pain relief were assessed hourly for 12 hr. The sum of pain intensity differences (SPID) from baseline and the total pain relief (TOTPAR) scores demonstrated a dose-response relationship for Codeine Contin on days 1 and 4 that was statistically significant on day 1 and suggested greater analgesic efficacy on day 4, compared with day 1. Codeine Contin 150 mg every 12 hr was estimated to be equianalgesic to acetaminophen plus codeine (600 mg/60 mg) given every 6 hr. Because a similar equivalence was also demonstrated from analysis of adverse event data, it is concluded that Codeine Contin 150 mg produces analgesia and a side-effect profile similar to a 40% lower dose of codeine provided by the combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

[Study of urinary excretion of codeine and morphine after oral ingestion of codeine].

Results of an investigation on the urinary excretion of codeine and morphine after oral ingestion of 1 mg.kg-1 b.w codeine are reported. The investigation run on seven clinically healthy subjects showed: low digestive absorption of codeine (# 20%); rapid biotransformation of codeine into morphine (first urines excreted after absorption); rapid disappearance of codeine from urines (#30 hrs); persistence of morphine alone (#68 hrs); rapid evolution of the codeine/morphine ratio (inversion of the ratio after #18 hrs); total elimination of morphine which can be greater than for codeine; very different half-life periods for codeine and morphine (5.1 and 13.6 hrs); no other codeine metabolites (nor-codeine and nor-morphine); very high individual variations; one subject with low activity of cytochrome P 450 dbl/buFL. Finally, in an epidemiological survey of drug addict behaviors and detection of drug addiction, it seems very difficult, may be even illusory and hazardous, to try and justify morphine found in urines (morphine, heroin, codeine, codethyline, pholcodine...) except in the very legitimate case where the ratio of urine concentrations of codeine and morphine is greater than one.

Administration, Oral↗

Abuse of codeine separated from over-the-counter drugs containing acetylsalicylic acid and codeine.

In Denmark a new trend concerning the abuse of codeine has been observed. Danish drug abusers have discovered that codeine is easily separated from certain drugs containing acetylsalicylic acid and codeine. When separated the codeine can be used either orally or intravenously. Three different drugs combining acetylsalicylic acid and codeine are available in Denmark, but codeine is only easily separable from one of these. Applying the same procedure to the two other drugs produces unpredictable or unfavourable ratios of codeine to acetylsalicylic acid. In several countries, however, similar drugs combining acetylsalicylic acid and codeine are available. It is not possible from a list of constituents to predict how easily codeine can be separated from a particular drug. Therefore it is strongly recommended that relevant drugs are tested at local forensic laboratories. In case codeine is found to be very easily separated from a product appropriate action should be taken.

Aspirin↗

Distribution of codeine and morphine into rat hair after long-term daily dosing with codeine.

Hair analysis for drugs of abuse provides a possible long-term measure of drug use not possible with urinalysis. Many drugs and their metabolites have been detected in hair; however, the factors influencing the incorporation of chemicals into hair are poorly understood. An animal model for chemical uptake into hair utilizing controlled drug administration was developed to ascertain if increasing doses of codeine are reflected in the concentrations of codeine and its metabolites found in hair. Male Sprague-Dawley rats were administered codeine at 5, 10, or 20 mg/kg (intraperitoneally; n = 6) daily for 21 days. At various times during and after the dosing protocol, approximately 50 mg of hair was shaved from a different area of the animals' backs and analyzed for codeine and morphine concentrations by ion-trap gas chromatography-mass spectrometry. Peak hair codeine concentrations for the 5-, 10-, and 20-mg/kg groups occurred 20 days after beginning the dosing protocol and were 0.57 +/- 0.13, 0.80 +/- 0.10, and 1.95 +/- 0.35 ng/mg hair, respectively. Morphine peak concentrations occurred at the same time and were 1.08 +/- 0.28, 1.21 +/- 0.09, and 2.10 +/- 0.26 ng/mg hair for the 5-, 10-, and 20-mg/kg groups, respectively. Long-term dosing in the rat resulted in similar or greater hair concentrations of morphine (metabolite) than codeine. The plasma pharmacokinetics of codeine and morphine were also obtained after a single, intraperitoneal codeine administration of 20 mg/kg. An experiment involving washing the rat hair with methanol or phosphate buffer (pH 9.0) did not reduce the concentration of codeine or morphine measured in hair as compared with nonwashed control hair. Data obtained in this study indicate that after controlled administration the incorporation of codeine and its metabolite, morphine, into rat hair occurs in a distinct dose-proportional manner.

Animals↗

Double-blind comparison of meclofenamate sodium plus codeine, meclofenamate sodium, codeine, and placebo for relief of pain following surgical removal of third molars.

A single-dose, randomized, double-blind, parallel-treatment study was performed in 200 outpatients with acute pain caused by the surgical removal of impacted third molars. Meclofenamate 100 mg plus codeine 60 mg, meclofenamate 50 mg plus codeine 30 mg, meclofenamate 100 mg, codeine 60 mg, and placebo treatment groups were compared for sum of pain intensity differences, peak pain intensity difference, sum of pain relief scores, peak pain relief, number of observations at which pain was half relieved, overall evaluation of effectiveness, and time to remedication with a backup analgesic. Meclofenamate 100 mg plus codeine 60 mg was significantly more effective (P less than .005) than codeine 60 mg for all variables except number of observations at which pain was half relieved. Both meclofenamate-codeine combinations and meclofenamate 100 mg alone were significantly more effective (P less than .005) than placebo for all variables. Eleven adverse experiences were reported in 7 patients (3.5%); the most common was somnolence in 1 patient receiving meclofenamate 100 mg plus codeine 60 mg, in 2 treated with meclofenamate 50 mg plus codeine 30 mg, and in 1 treated with codeine 60 mg.

Adolescent↗

A double-blind study of diflunisal and codeine compared with codeine or diflunisal alone in postoperative pain.

A double-blind, randomized, parallel-group study compared the analgesic efficacy of a single oral dose of 500 mg diflunisal, 60 mg codeine, 500 mg diflunisal plus 60 mg codeine given as separate agents, and placebo in 161 patients with moderate to severe postoperative pain. Standard subjective measures were used to evaluate analgesia. Eight-hour sum of pain intensity differences and total pain relief scores for all active treatments were significantly better than were those for placebo (p less than 0.05). Diflunisal plus codeine performed the best followed by diflunisal, codeine, and placebo. Diflunisal plus codeine was better than placebo from 1 1/2 to 8 hours (p less than 0.01), better than codeine from 1 1/2 to 6 hours (p less than 0.05), and better than diflunisal alone from 1/2 to 1 1/2 hours (p less than 0.05) for most measures of analgesia. Factorial analysis demonstrated a significant early codeine effect and a significant diflunisal effect throughout. No significant treatment group differences were observed regarding adverse effects. Our data demonstrate that diflunisal plus codeine is generally well tolerated and provides analgesia superior to that of diflunisal or codeine alone in the treatment of moderate to severe postoperative pain.

Adult↗

Plasma codeine and morphine concentrations after a single oral dose of codeine phosphate.

Plasma concentrations of codeine and its O-demethylated metabolite morphine were determined, by a sensitive and specific high performance liquid chromatography (HPLC) method, following a single oral dose of 60 mg codeine phosphate. Ten healthy volunteers received a single dose of 60 mg codeine phosphate. The plasma concentrations were analyzed for codeine and morphine at the 0.5, 1, 3, and 6 hours postdosing. The mean peak codeine plasma concentrations and tmax (time to reach maximum plasma codeine concentrations) were 88.1 ng/mL and 1.2 hours. Mean maximum concentrations of metabolically produced morphine was 2.7 +/- 0.6 ng/mL. The mean ratio of areas under the plasma concentration-time curves for morphine and codeine was 0.027. Thus, free morphine represented only about 2.7 +/- 1.8% of the free codeine area in each case.

Administration, Oral↗

Effects of morphine, codeine and codeine-epoxide on calcium uptake into the synaptosomes isolated from naive and tolerant rats.

We studied the effects of morphine, codeine and codeine-7,8-oxide (codeine-epoxide) on the stimuli-induced 45Ca2+ uptake into the synaptosomes isolated from naive and tolerant rats and clarified the relationship between pharmacological responses of opiates and synaptosomal 45Ca2+ uptake. In vitro additions of morphine and codeine-epoxide inhibited the synaptosomal 45Ca2+ uptakes induced by two stimuli, that is, high KCl and veratrine in a concentration-dependent manner; and the inhibitions could be reversed by naloxone. However, the inhibitory action of codeine was less than that of morphine and codeine-epoxide. Since the potency ratios of the anti-nociceptive action of opiates are higher in the order of morphine greater than codeine-epoxide greater than codeine, the inhibitory effect of opiates on synaptosomal 45Ca2+ uptake may partly relate to their antinociceptive action. On the other hand, opiates significantly increased synaptosomal 45Ca2+ uptake when animals were rendered tolerant to their antinociceptive action, and data showed that the elevation of stimuli-induced 45Ca2+ uptake into the synaptosomes isolated from tolerant animals may reflect the degree of antinociceptive tolerance. Our results support the hypothesis that some of the pharmacological effects of opiates may be attributable to its ability to affect calcium accumulation in synaptosomes.

Analgesics↗

Ratios of total morphine to total codeine in urine of subjects consuming medicinal preparations containing morphine or codeine and in drug abusers.

Urinary total morphine: total codeine ratios were studied in two groups of people. Group A consisted of 76 subjects receiving three different medicinal preparations containing morphine or codeine, while Group B consisted of 33 drug abusers detected at urinary mass screening. Distinct differences in these ratios were observed. In Group A, total morphine: codeine ratios of 1:2.6 and below were obtained for subjects consuming either Tablet Codeine Co or Syrup Phensedyl. Subjects consuming Kaolin et Morphine mixture did not excrete any codeine in the urine. In Group B, total morphine: total codeine ratios of 1.9:1 and above were obtained. In addition all subjects in Group B excreted both morphine and codeine. The clear separation of the morphine: codeine ratios makes this a possible index to differentiate between these groups.

Codeine↗

Tramadol hydrochloride: analgesic efficacy compared with codeine, aspirin with codeine, and placebo after dental extraction.

Tramadol hydrochloride is a novel, centrally acting analgesic with two complementary mechanisms of action: opioid and aminergic. Relative to codeine, tramadol has similar analgesic properties but may have fewer constipating, euphoric, and respiratory depressant effects. A two-center randomized double-blind controlled clinical trial was performed to assess the analgesic efficacy and reported side effects of tramadol 100 mg, tramadol 50 mg, codeine 60 mg, aspirin (ASA) 650 mg with codeine 60 mg, and placebo. Using a third molar extraction pain model, 200 healthy subjects were enrolled in a 6-hour evaluation after a single dose of drug. Of the 200 patients enrolled, seven provided incomplete efficacy data or discontinued prematurely and one was lost to follow-up. Using standard measures of analgesia, including total pain relief score (TOTPAR), maximum pain relief score (MaxPAR), sum of pain intensity difference scores (SPID), peak pain intensity difference (Peak PID), remedication, and global evaluations, all active treatments were found to be numerically superior to placebo. ASA/codeine was found to be statistically superior to placebo for all measures of efficacy. Tramadol 100 mg was statistically superior to placebo for TOTPAR, SPID, and time of remedication, whereas tramadol 50 mg was statistically superior to placebo onlyfor remedication time. Codeine was not found to be statistically superior to placebo for any efficacy measure. A greater TOTPAR response compared with all other active measures was seen for ASA/codeine during the first 3 hours of study. The 6-hour TOTPAR scores for the tramadol groups and ASA/ codeine group were not significantly different. Gastrointestinal side effects (nausea, dysphagia, vomiting) were reported more frequently with tramadol 100 mg, ASA/ codeine, and codeine 60 mg than with placebo.

Adolescent↗