Continuous monitoring of plasma antiepileptic drug levels.

Quantitative knowledge of the fate of antiepileptic drugs in individual patients is useful in the prevention, explanation, and correction of subtherapeutic and toxicity-causing regimens. Several variables, such as age and co-medication, require adaptation of the regimen. An interactive computer-assisted laboratory reporting service provides a data base with epidemiological options that helps in the daily management of patients and can supply information on pharmacokinetic parameters, local, regional, and national drug utilization, and disease frequency. Some treatment variables are quantitatively predictable, but many others require individual monitoring of clinical, behavioral, and laboratory observations by a multidisciplinary team of experts. Intensive monitoring by an epilepsy team in an institution for mentally retarded patients has allowed conclusions on the value of therapeutic substances, reduction of the number of simultaneously administered drugs, and seizure registration.

Effects of alcohol consumption on pharmacokinetics, efficacy, and safety of fluvastatin.

Alcohol consumption is known to have beneficial effects on cardiac mortality, probably by increasing high density lipoprotein cholesterol (HDL-C). Alcohol also increases triglycerides and, in some studies, total cholesterol and low density lipoprotein cholesterol (LDL-C). Nothing is known, however, of the effects of alcohol on the pharmacokinetics and efficacy of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors. Consequently, 2 studies have been carried out to determine the effects of alcohol consumption on the pharmacokinetics and efficacy of the HMG-CoA reductase inhibitor fluvastatin. Firstly, the effects of acute alcohol consumption on a single, oral 40 mg dose of fluvastatin were examined in a reference-controlled, randomized, crossover study in 10 healthy volunteers. Measurements were made after ingestion of 70 g of ethanol diluted to 20% with lemonade and, following a 7-day period, after ingestion of lemonade alone (reference). The half-life (t1/2) of a single dose of fluvastatin was significantly reduced by acute alcohol consumption compared with reference, whereas the area under the time-concentration curve (AUC), peak concentration (Cmax), and time to peak concentration (tmax) did not differ from the reference group. The lipid profile, measured 8 hr after administration, did not differ significantly from baseline in the reference group, apart from a slight reduction in apolipoprotein (apo)-AI. Triglyceride levels increased with alcohol, probably due to impaired fatty acid oxidation. Surprisingly, total cholesterol and LDL-C fell significantly, possibly due to altered pharmacokinetics, as reflected by the lower t1/2.(ABSTRACT TRUNCATED AT 250 WORDS)

Intermittent cyclophosphamide with prednisone versus placebo for polyneuropathy with IgM monoclonal gammopathy.

BACKGROUND: The best treatment for polyneuropathy associated with IgM monoclonal gammopathy (MGUS) is unknown. Oral cyclophosphamide combined with prednisone showed limited efficacy in a previous open label pilot study. We therefore performed a double-blind, randomized, placebo-controlled study of combined oral cyclophosphamide and prednisone in IgM MGUS polyneuropathy. METHODS: Thirty-five patients with progressive IgM MGUS polyneuropathy were included. After stratification for anti-MAG antibodies patients were randomized to oral cyclophosphamide 500 mg once daily for 4 days combined with oral prednisone 60 mg once daily for 5 days (treatment) (n = 16), or placebo (n = 19), repeated every 28 days for six times. Primary outcome was improvement of the Rivermead Mobility Index (RMI). Secondary outcomes were improvement of the modified Rankin scale, Medical Research Council and sensory sum scores, levels of M protein, EMG, and Short Form-36 scale after treatment. Patients were examined at 0, 6, 12, 18, and 24 months. RESULTS: After 6 months of treatment and at later follow-up, no difference in change of the RMI between the two groups was observed. Change of the Rankin scale was similar in both groups. Other outcome parameters showed more improvement in the treatment group: the MRC sum score improved more from 6 to 24 months after treatment; the sensory sum score improved more at 6 months; the SF 36 mean health change score and physical role score improved more; and the median nerve distal conduction (abductor pollicis brevis muscle) improved more in the treatment group. The most common adverse event was nausea. CONCLUSIONS: Compared with placebo treatment, this first double-blind randomized trial with cyclophosphamide and prednisone in IgM MGUS polyneuropathy showed no beneficial effect on the functional scales, but a beneficial effect on muscle strength and sensation was observed.

Pharmacokinetics of di-n-propylacetate in epileptic patients.

The pharmacokinetics of the anti-epileptic drug di-n-propylacetate (DepakineR) have been studied in 7 patients, in whom plasma concentrations were determined during and following subchronic treatment. Elimination of the drug appeared to follow a monophasic exponential course; biological half lives were 8 to 15 hours. The data supported the assumption that an open one-compartment model can be used to describe the kinetics of dipropylacetate in man. The drug appeared to have a relatively restricted distribution: calculated relative distribution volumes ranged from 0.15 to 0.40 1/kg. There were large interindividual differences in clearance rate. The therapeutic range was considered to be between 50 and 100 mg/1 plasma. Plasma levels of phenobarbital were markedly raised during treatment with dipropylacetate for an unknown reason. Determination of the plasma concentrations of drugs at accurately fixed times appears to be a reliable method for pharmacotherapeutic monitoring of epileptic patients.

Therapeutic monitoring of valproic acid.

Valproic acid, a new type of antiepileptic drug, has developed into one of the drugs of first choice in all types of epilepsy with the exception of infantile spasms and partial seizures. Due to its short biological half-life, a steady-state plasma concentration will be reached rapidly after initiation of therapy. However, no direct relationship between this plasma concentration and the clinical effect can be found. In autoradiography experiments, brain distribution appears to change with time, suggesting a gradual accumulation of the drug or its metabolites in certain brain areas. Two metabolites are detected in monkey and human blood plasma. Valprolactone is also found in brain tissue, but the substance is rapidly eliminated. beta, gamma-Unsaturated valproic acid has the longest half-life and is found in concentrations that can be quantitated by routine gas chromatographic analysis. The therapeutic effect appears to correlate better with dosage per kilogram body weight than with the actual plasma concentrations. Routine monitoring of valproate plasma concentrations in epileptic patients seems to be of limited value.

Outcome measures for the assessment of new antiepileptic drugs.

For the approval of any new medicinal product quality, safety and efficacy are essential requirements. This manuscript focuses on the clinical development programme. For the investigation of antiepileptic drugs some international guidelines are of special importance. They are based on the knowledge of many experts and can be seen as a consensus on minimal requirements; deviations must be thoroughly justified. In phases II and III, usually randomised, double-blind add-on studies versus placebo in patients with therapy-resistant seizures are used to get an impression of the efficacy and certain safety issues. A clear dose-response relationship may be a good indication for efficacy. However, assessment of safety of the new product in add-on studies is difficult. Therefore comparative phase III monotherapy studies versus established antiepileptic drugs are essential to confirm the results obtained in add-on studies and are needed for a proper judgement of the efficacy/safety balance. The percentage of reduction of seizure frequency has played a dominating role as efficacy criterium. Nowadays preference is being given to the percentage responders. Which parameter is the most relevant for the given group of patients and what change is considered clinically relevant must be thoroughly argued. The definition of responder should focus on major benefit for the patients involved.

Preliminary study of pharmacokinetics and metabolism of sodium 2-n-propylpentanoate in pig and human.

The pharmacokinetics of sodium 2-n-propyl-pentanoate have been studied in pig and human. The drug is excreted in the human urine as a mixture of glucuronide and other unidentified conjugates. It appears that no other conjugates can be found in pig's urine. Treatment with sulfatase does not identify sulfate-conjugates in human urine. Coadministration of acetyl salicylic acid (ASA) increases the fraction of glucuronide and other conjugates in human urine. The rate of renal excretion of the drug appears to be increased during concomitant administration of ASA.

Effects of alcohol and fluvastatin on lipid metabolism and hepatic function.

OBJECTIVE: To determine the effects of fluvastatin, a synthetic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, combined with moderate alcohol consumption on lipid profiles and hepatic function in patients with primary hypercholesterolemia. DESIGN: Randomized, placebo-controlled, crossover study. SETTING: Lipid clinic of a university hospital. PATIENTS: 31 patients with primary hypercholesterolemia (low-density lipoprotein cholesterol levels > or = 4.2 mmol/L) who had previously received a lipid-lowering diet. INTERVENTIONS: After a dietary baseline period, 26 patients were randomly assigned to receive 6 weeks of treatment with either 1) fluvastatin, 40 mg/d, added to 20 g of ethanol and diluted to 20% with orange juice or 2) fluvastatin added to orange juice alone. After a 6-week washout period, the two groups crossed over. MAIN OUTCOME MEASURES: Plasma fluvastatin levels, lipid levels, and clinical variables were determined at the end of each treatment period. RESULTS: Six patients left the study prematurely. The remaining patients (15 men, 5 women; mean age +/- SD 49.1 +/- 14.5 years; mean body mass index +/- SD 24.5 +/- 2.2 kg/m2) completed the study. Fluvastatin, alone and combined with alcohol, resulted in similar decreases in levels of total cholesterol (22% and 23%, respectively; P < 0.001 when compared with baseline), low-density lipoprotein cholesterol (28% and 29%, respectively; P < 0.001 compared with baseline), and apolipoprotein B (17% and 20%, respectively; P < 0.001 compared with baseline). High-density lipoprotein cholesterol and triglyceride levels were not changed. Fluvastatin with alcohol resulted in a significantly greater area under the plasma concentration curve (23.4 +/- 4.7 compared with 18.2 +/- 3.2 x 10(3) ng.min/mL) and in a greater time to maximum concentration (187.5 +/- 16.6 min compared with 130.9 +/- 7.0 min) than fluvastatin alone. Terminal half-life tended to increase. No important adverse clinical effects were observed. CONCLUSION: Six weeks of daily, moderate alcohol consumption influenced the metabolism of fluvastatin but did not interfere with its lipid-lowering efficacy and had no adverse effects.