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Biomedical subjects

F Pisani

Publications and source records attributed to F Pisani.

At least 91 records · Page 5Linked to original sources
PubMed1993

Lamotrigine in resistant childhood epilepsy.

Fourteen children (6 M, 8 F) suffering from refractory epilepsy received LTG as add-on therapy. LTG was administered twice daily at dosages increasing up to 2 mg/kg/day (for patients taking VPA) or to 10 mg/kg/day for patients taking AEDs that induce hepatic metabolism. The drug was withdrawn for side effects in 3 cases (rash: two cases, hirsutism: one), because of increased seizure frequency in 2 cases and because of unchanged seizure frequency in one. One patient died from acute respiratory failure, after repeated respiratory tract infections. A decrease in seizure frequency after one year of treatment with LTG was observed in 6 of the 7 patients who completed the study. The median total seizure frequency decreased from 10.7 +/- 7.3 to 3.8 +/- 4.6 seizures per day. At the end of the study, seizure frequency had decreased by more than 50% in 2 patients, by more than 75% in 2 patients, and 2 patients were seizure-free; in the remaining patient seizure frequency was unchanged. The best results were obtained with plasma LTG concentrations ranging from 0.5 to 5.4 micrograms/ml; no further improvement was observed at higher LTG concentrations.

Adolescent↗
PubMed1993

Carbamazepine coadministration with fluoxetine or fluvoxamine.

To study the potential interaction between carbamazepine (CBZ) and selective serotonin reuptake inhibitors, fluoxetine (20 mg/day) and fluvoxamine (100 mg/day) were administered for 3 weeks to eight and seven epileptic patients, respectively, on chronic CBZ treatment. No significant changes in steady-state plasma concentrations of CBZ and its active metabolite, carbamazepine-10,11-epoxide (CBZ-E) occurred, suggesting that CBZ metabolism is probably not affected by fluoxetine or fluvoxamine administration.

Adult↗
PubMed1993

Vigabatrin-induced decrease in serum phenytoin concentration does not involve a change in phenytoin bioavailability.

The possibility that vigabatrin (VGB) decreases serum phenytoin (PHT) concentration by lowering the oral bioavailability of PHT was investigated in 21 patients with epilepsy. Each patient was switched from oral to intravenous PHT for 5 days before and after combined treatment with VGB. After VGB (2-3.5 g day(-1) for at least 5 weeks), serum PHT concentrations decreased slightly from 87 +/- 25 to 76 +/- 31 micromol l(-1) (means +/- s.d., P < 0.05), but in a subgroup of seven patients the decrease was more prominent (from 72 +/- 22 to 49 +/- 17 micromol l(-1), P < 0.005). At baseline (before VGB), serum PHT remained unaffected (85 +/- 30 micromol l(-1)) after switching PHT dosage to the intravenous route, indicating that the oral availability of the drug was virtually complete. During VGB treatment, serum PHT was also unchanged (74 +/- 34 micromol l(-1)) after switching from oral to intravenous therapy, and this was also true for the subgroup of patients showing a prominent interaction (48 +/- 18 micromol l(-1)). The urinary recoveries of PHT and its metabolites pHPPH and mHPPH remained constant throughout the study. It is concluded that the oral availability of PHT is unaffected by VGB and that the VBG-induced decrease in serum PHT is mediated by alternative mechanisms.

Adolescent↗
PubMed1993

[Surgical complications in renal transplantation].

Technical complications in kidney transplantation are unusual but with a high incidence of graft loss and mortality. The authors report their experience with 89 kidney transplants with an overall incidence of 16.8%. Only early and aggressive surgical procedures can resolve certain of the complications.

Adolescent↗
PubMed1992

Influence of co-medication on the metabolism of valproate.

Valproate is extensively metabolized in the liver and at least six main pathways which produce about 50 metabolites have been identified in man. The enzyme-inducing antiepileptic drugs phenobarbital, primidone, phenytoin and carbamazepine increase total valproate clearance by 30-85%, whereas cimetidine and the new anticonvulsant compound striripentol display a small inhibitory effect (10-20%). Both carbamazepine and phenytoin induce a two-fold increase in the formation of delta 4-valproate and stimulate omega-oxidation and omega-1-oxidation. Acetylsalicylic acid causes a fall of 60-70% in the content in the urine of the metabolites of the beta-oxidative pathway, i.e. delta 2-valproate, 3-OH-valproate and 3-oxo-valproate, and an increase of glucuronidation (approximately 30%) and delta-dehydrogenation (approximately 20%). Stiripentol inhibits the formation clearance of delta 4-valproate by 30%. In the light of the possible therapeutic and toxic effects of some valproate metabolites, drug interactions with valproate at metabolic level may have important clinical implications.

Anticonvulsants↗
PubMed1992

A liquid chromatographic assay using a high-speed column for the determination of lamotrigine, a new antiepileptic drug, in human plasma.

A sensitive, specific and rapid liquid-chromatographic method for the determination of the new antiepileptic drug lamotrigine (LTG) in human plasma is described. The method involves the use of a commercially available 3-microns particle size normal-phase column and a microflow-cell-equipped ultraviolet detector. Extraction is carried out with ethyl acetate after alkalinization on a 100-microliters plasma sample containing LTG and 3,5-diamino-6-(2-methoxyphenyl)-1,2,4-triazine as internal standard. The residue is reconstituted with 50 microliters of ethanol, and 5 microliters of the final solution is injected into the column. Elution is carried out at 35 degrees C using n-hexane/absolute ethanol/35% ammonia (80/20/0.25 by volume) as mobile phase at a flow rate of 2.0 ml/min. Detection is at 313 nm. The chromatographic separation requires < 3 min and the sensitivity limit is < 0.1 mg/L. Recovery is 88-96.2%, whereas within-day and day-to-day coefficients of variation are between 4.1 and 7.7%.

Anticonvulsants↗
PubMed1992

Impairment of carbamazepine-10, 11-epoxide elimination by valnoctamide, a valpromide isomer, in healthy subjects.

The effect of the valpromide isomer valnoctamide (VCD, 200 mg three times daily for 8 days), an over-the-counter tranquillizer, on the elimination kinetics of a single oral dose of carbamazepine-10, 11-epoxide (CBZ-E, 100 mg) was investigated in healthy subjects. During VCD treatment, the half-life of CBZ-E was prolonged significantly compared with control (19.7 +/- 6.7 h vs 6.9 +/- 2.0 h, means +/- s.d., P less than 0.01), and its oral clearance decreased four-fold (from 109.6 +/- 30.7 to 28.8 +/- 11.1 ml h-1 kg-1, P less than 0.01). These findings indicate that VCM, like valpromide, strongly inhibits epoxide hydrolase in vivo.

Administration, Oral↗
PubMed1992

Elevation of plasma phenytoin by viloxazine in epileptic patients: a clinically significant drug interaction.

The effect of viloxazine (150-300 mg daily for 21 days) on plasma phenytoin levels at steady state was examined in 10 epileptic patients stabilised on a fixed phenytoin dosage. After starting viloxazine treatment, plasma phenytoin concentrations increased by 37% on average (range 7-94%) from a mean value of 18.8 micrograms/ml at baseline to a mean value of 25.7 micrograms/ml during the last week of combined therapy. In four patients the rise in plasma phenytoin was associated with the development of signs of phenytoin toxicity. Discontinuation of viloxazine resulted in return of plasma phenytoin towards baseline values and disappearance of the clinical symptoms. The mechanism of interaction probably involves inhibition of phenytoin metabolism by viloxazine. Careful monitoring of plasma phenytoin levels is recommended in patients treated with phenytoin who need to be started on viloxazine therapy.

Adult↗
PubMed1991

Non-Hodgkin lymphomas of the central nervous system.

Non-Hodgkin lymphomas (NHL) of the Central Nervous System (CNS) are rare but they nonetheless constitute a clinical, biological and therapeutic problem of great interest. Primary lymphomas of the CNS account for 2% of all malignant lymphomas and for 0.3-1.5% of all intracranial tumors. Surgery and radiotherapy afford only poor control of the disease. The most satisfactory results have been achieved with combination therapy, surgery + radiotherapy + chemotherapy, but the optimal combination has still to be devised. Secondary neuromeningeal involvement affects a fair number of patients with systemic NHL. The symptoms are broadly the same as in CNS NHL and the treatment as problematic. There have recently been suggestions that the onset of CNS NHL may be exacerbated by immunodeficiency states such as occur in patients who have undergone organ transplantation, in autoimmune disease and, still more recently, in the acquired immunodeficiency syndrome (AIDS). The frequency of these tumors is anyway on the increase and a better insight into the disease in essential.

Acquired Immunodeficiency Syndrome↗