The comparative bioavailability of an extended-release niacin and lovastatin fixed dose combination tablet versus extended-release niacin tablet, lovastatin tablet and a combination of extended-release niacin tablet and lovastatin tablet

Lovastatin and extended-release (ER) niacin in a fixed dose combination (Advicor) is approved for the treatment of dyslipidemia. Since both drugs are extensively metabolized, this study investigated the bioavailability and pharmacokinetics of their co-administration following single-dose administration. In a 4-way crossover study 40 subjects received: two 1000/20 Advicor tablets (ADV), two 1000 mg niacin ER tablets (NSP), two 20mg lovastatin tablets (Mevacor; MEV), and two niacin ER 1000 mg tablets with two lovastatin 20mg tablets (NSP+MEV). Plasma was assayed for niacin, nicotinuric acid (NUA), lovastatin, lovastatin acid and HMGCoA reductase inhibition. Urine was assayed for niacin and its metabolites, NUA, N-methylnicotinamide and N-methyl-2pyridone-5-carboxamide. Least square mean ratios and 90% confidence intervals for C(max) and AUC((0-t)) were determined for NSP+MEV versus MEV or NSP, ADV versus MEV or NSP, and ADV versus NSP+MEV. Co-administration of niacin and lovastatin did not significantly influence C(max) and AUC((0-t)) of lovastatin, niacin, NUA and total urinary recovery of niacin and metabolites. A 22 to 25% decrease in lovastatin acid C(max) was observed while lovastatin acid AUC((0-t)) was not affected. The HMGCoA reductase inhibition C(max) and AUC((0-t)) were not affected indicating that the difference in lovastatin acid C(max) was not clinically relevant.

N-0923, a novel soluble dopamine D2 agonist in the treatment of parkinsonism

N-0923, a novel aminotetralin dopamine D2 agonist, was shown to effectively reverse parkinsonian symptoms in nine dopa/agonist-responsive Parkinson's disease patients. The drug was given up to 4.5 hours by continuous intravenous (i.v.) infusion using an i.v. pump. The onset of anti-parkinsonian effect was seen within minutes of the initiation of the infusion and was absent within 90 minutes of cessation of the infusion. The short elimination half-life of N-0923 (90 min) would allow for the rapid initiation of drug effect when necessary and at the same time permit the effect to be terminated quickly if necessary. The drug would be useful in situations where oral medication is not feasible or is associated with erratic absorption. The patients tolerated the drug well. Dose escalation load was limited by nausea and vomiting. It should be noted that the doses were increased until these symptoms occurred, but therapeutic effects were noted well before the side effects occurred. Using a modified Columbia scale, maximum improvement consisted of a 27-95% drop in score. Maximum response was obtained at infusion rates varying from 2-16 microg/kg per hour and at blood levels of 0.11-1.49 microg/mL.

Pharmacokinetics of procainamide in continuous ambulatory peritoneal dialysis

Procainamide (PA) and N-acetylprocainamide (NAPA) pharmacokinetics were examined in six patients undergoing continuous ambulatory peritoneal dialysis (CAPD) following a single oral dose of 625 mg of procainamide HCl. Peak serum PA concentrations occurred between 1 and 3 h after drug administration whereas peak NAPA levels were reached 14 to 48 h following the administration of PA. NAPA levels 1.2 mcg/ml or greater were present for 72 h and in four of the six subjects little further decline occurred at 96 h. PA total body clearance (TBC) averaged 143 ml/min; TBC for NAPA was 29.8 ml/min. PA and NAPA half-lives were considerably prolonged averaging 26.0 and 42.8 h, respectively. V beta for PA was 4.1 l/kg and for NAPA was 1.46 l/kg. PA and NAPA dialysance varied from 0.28 to 5.55 ml/min and from 1.74 to 7.20 ml/min, respectively. This, in turn, represented less than 5 and 25% of the TBC for each drug.