British journal of clinical pharmacology
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The metabolism of morphine was studied in seven fullterm neonates and five infants receiving a continuous infusion of morphine. All the patients had detectable plasma concentrations of morphine 3-glucuronide (M3G) and 10 had detectable concentrations of morphine 6-glucuronide (M6G). The mean plasma clearance of morphine was 20.1 ml min-1 kg-1 in neonates and 23.4 ml min-1 kg-1 in the group as a whole. The M3G/morphine ratio (7.3) was higher than that previously reported for preterm neonates (5.0) but lower than that reported for children (23.9).
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Br J Clin Pharmacol · Jul 1992
The influence of renal function on the renal clearance of morphine and its glucuronide metabolites in intensive-care patients.
1. The relationships between renal creatinine clearance and the renal clearances of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were studied in fifteen intensive-care patients who were receiving morphine sulphate by constant intravenous infusion and who had diverse renal function. 2. An arterial blood sample was collected before and after a 4-5 h urine collection. ⋯ In ten of the patients who received a constant infusion of morphine for at least 6 h, the dose-normalised plasma concentrations of M3G and M6G increased with decreasing CLCr,pred. Significant (P less than 0.001) relationships were observed between the reciprocal of CLCr,pred and the dose-normalised plasma concentrations of M3G and M6G. 5. The results indicate the importance of renal function in determining the renal clearances and plasma concentrations of M3G and M6G during intravenous infusion with morphine in intensive-care patients.
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Br J Clin Pharmacol · Feb 1992
Randomized Controlled Trial Clinical TrialA comparison of the effect of salmeterol and salbutamol in normal subjects.
1. The effects of salmeterol hydroxynaphthoate (50 micrograms, 8.3 x 10(-8) M) and salbutamol (200 micrograms, 3.5 x 10(-7) M) on sGaw were compared in a double-blind, placebo-controlled, randomised study in 10 normal subjects. 2. ⋯ The mean area under the sGaw-time curve (AUC480) after salmeterol inhalation was 22,500 kPa-1 (10,100-39,500) compared with 14100 kPa-1 (8020-24,500) after salbutamol and 5300 kPa-1 (1500-10,400) after placebo. 4. Salmeterol produced a significantly prolonged bronchodilator effect compared with salbutamol in normals.
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Br J Clin Pharmacol · Dec 1991
Randomized Controlled Trial Comparative Study Clinical TrialGastric emptying in healthy volunteers after multiple doses of levodopa.
1. Oral levodopa frequently produces an episodic delay in gastric emptying which leads to multiple peak concentrations of the drug in plasma. We have studied the effects of multiple dosing of levodopa on gastric emptying and levodopa absorption in eight healthy young volunteers in a randomised two-way cross-over study. 2. ⋯ The area under the plasma concentration-time curves (AUC) for the final dose of levodopa (150.8 +/- 22.0 micrograms ml-1 min) was lower than for the two preceding doses (205.7 +/- 41.8 and 199.5 +/- 51.8 micrograms ml-1 min) but not different from that of the single dose given at the same time of day (141.7 +/- 29.1 micrograms ml-1 min). This indicates that the lower AUC of the final dose of levodopa was related to the time of administration and not a result of the two preceding doses. 4. The absence of any significant effects of preceding doses of levodopa on gastric emptying was confirmed a) by co-administration of soluble paracetamol, as a marker of gastric emptying, with the second dose of levodopa or placebo and b) by co-administration of radiolabelled DTPA and gamma-camera imaging with the final dose of levodopa on the multiple dosing day and the single dose of levodopa on the placebo day.(ABSTRACT TRUNCATED AT 250 WORDS)