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Biomedical subjects

A Ylinen

Publications and source records attributed to A Ylinen.

60 records · Page 4Linked to original sources

Reduction of dosing frequency of carbamazepine with a slow-release preparation.

The occurrence of side effects and epileptic seizures and the pharmacokinetics of carbamazepine (CBZ) and carbamazepine-10,11-epoxide were studied using a slow-release CBZ preparation, Neurotol slow, and a conventional CBZ preparation, Tegretol. The study was an open, randomized cross-over trial, with a 2 week study period for each preparation. Tegretol was given 3 times and Neurotol slow twice a day. The earlier CBZ dose was kept unchanged. The initial sample consisted of 24 adult epileptic patients receiving CBZ treatment of whom 20 patients were evaluable. The fluctuation in serum CBZ concentrations did not differ significantly between the 2 treatment periods, even though the interdose interval of Neurotol slow was 4 h longer than that of Tegretol. The switch-over from conventional CBZ to the slow-release formulation did not seem to alter the efficacy and side effects of CBZ. By using Neurotol slow instead of a conventional CBZ preparation, Tegretol, it is evidently possible to reduce the dosing frequency from 3 times a day to twice daily administrations.

Adolescent↗

Inhibitory and excitatory amino acids in CSF of patients suffering from complex partial seizures during chronic treatment with gamma-vinyl GABA (vigabatrin).

The effect of chronic administration of gamma-vinyl GABA (GVG; vigabatrin) on levels of neurotransmission-related amino compounds was studied in lumbar cerebrospinal fluid of 65 patients with complex partial epilepsy. The first sample of cerebrospinal fluid was taken before a 3-month period of treatment with 3 g gamma-vinyl GABA/day, and the second was taken afterwards. From patients who showed a greater than 50% reduction in seizures (responders) or marked improvement in global performance, a third sample was taken at the end of the next 3-month phase, during which 3 g or 1.5 g gamma-vinyl GABA had been administered daily. During treatment with 3 g gamma-vinyl GABA/day, 55% of the patients showed more than 50% reduction in complex partial seizures; and at the same time free GABA, total GABA, homocarnosine, and glycine concentrations in the cerebrospinal fluid increased by 104%, 151%, 194% and 16%, respectively. After reduction of the daily dose to 1.5 g, the levels of free GABA, total GABA and homocarnosine were still increased by 65%, 115% and 102%, respectively. gamma-Vinyl GABA correlated with the levels of free GABA (P less than 0.002) and glycine (P less than 0.001). Concentrations of homocarnosine at baseline and homocarnosine and total GABA during gamma-vinyl GABA treatment were lower (P less than 0.005) in the group of non-responders than in the responder group. Glutamic acid, glutamine, aspartic acid, asparagine, and taurine levels did not change during gamma-vinyl GABA treatment. In conclusion, administration of gamma-vinyl GABA reduces epileptic seizures and produces dosage-dependent increases in levels of free GABA, GABA-containing peptides and of glycine in cerebrospinal fluid, without concomitant change in levels of excitatory amino acids.

Adolescent↗

Double-blind dose reduction study of vigabatrin in complex partial epilepsy.

Seventy-five epilepsy patients with at least two complex partial seizures/month were treated with gamma-vinyl GABA (GVG) 3 g/day for 3 months. Forty-one patients (54%) showed a reduction of greater than or equal to 50% in seizures. The median monthly seizure frequency decreased from 11.5 to 4 seizures/month. Twenty percent of patients had an improvement in general performance without a significant reduction in seizures. The responders entered the second phase of the study, in which 28 patients were randomly allocated to 3 g/day and 25 patients to 1.5 g/day GVG under double-blind conditions. The dosage of 3 g/day appeared to be clearly more effective than 1.5 g/day. However, even with 1.5 g/day GVG the seizure frequency was significantly reduced as compared to baseline. Drowsiness was the most commonly observed side effect, and it diminished with continued treatment. In three cases side effects led to the withdrawal of GVG therapy.

Adolescent↗

Double-blind study of Gabapentin in the treatment of partial seizures.

Forty-three patients completed a double-blind, placebo-controlled study of Gabapentin (GBP) as add-on therapy in partial and secondarily generalized seizures. All patients were followed for an initial 3-month baseline period, after which they were randomly allocated to receive either a placebo or 900 or 1,200 mg/day GBP for 3 months. A statistically significant difference in seizure frequency from the baseline to the treatment phase was noted between patients receiving placebo and GBP 1,200 mg, in whom seizure frequency decreased 57%. The GBP dosage of 900 mg appeared to be ineffective. A close relationship was observed between the serum GBP concentrations and the GBP dosage based on the seizure frequency. Serum GBP concentrations greater than 2 micrograms/ml resulted in a lower frequency of seizures. The adverse effects were minor and consisted mainly of transient drowsiness. GBP appears to be effective in the treatment of partial epileptic seizures in a dosage-related manner.

Acetates↗

Gamma-vinyl GABA (vigabatrin) in epilepsy: clinical, neurochemical, and neurophysiologic monitoring in epileptic patients.

We report long-term clinical, neurochemical, and electrophysiologic data of gamma-vinyl GABA (GVG, vigabatrin) in three groups of patients. GVG was started as add-on therapy for 75 patients with refractory complex partial seizures (group A) and for 36 mentally handicapped patients with severe epilepsy (group B). The third group (C) consisted of 20 patients with carbamazepine (CBZ) monotherapy, in half of whom GVG monotherapy was substituted. After 3 months, 55% of patients in group A and 42% in group B were responders (reduction in seizure frequency greater than 50%). After 6 (group A) and 3 years (group B) of follow-up, 27 and 33% of the patients, respectively, still had good response to GVG. Neurochemical measurements showed a twofold increase in CSF GABA concentrations and minimal or no changes in other neurotransmitter-related parameters. In group C, substitution of GVG as medication tended to normalize the lengthened latencies in somatosensory evoked potentials (SEPs) observed during CBZ treatment.

Adult↗