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Biomedical subjects

G Honigfeld

Publications and source records attributed to G Honigfeld.

At least 19 recordsLinked to original sources
PubMed1991

Clozapine-related seizures.

Clozapine is an atypical antipsychotic drug with minimal extrapyramidal toxicity recently approved by the Food and Drug Administration for hard-to-treat schizophrenic patients. We reviewed information on 1,418 patients treated with clozapine in the United States between 1972 and 1988. Forty-one of 1,418 (2.8%) patients had generalized tonic-clonic seizures during treatment with clozapine. Life-table analysis predicts a cumulative 10% risk of seizures after 3.8 years of treatment. Clozapine-related seizures appear to be dose-related. High-dose therapy (greater than or equal to 600 mg/day) was associated with a greater risk of seizures (4.4%) than medium (300 to 600 mg/day; 2.7%) or low doses (less than 300 mg/day; 1.0%). Also, rapid upward titration may increase seizure risk. Thirty-one of 41 patients were successfully continued on clozapine despite seizure occurrence, either with reduction of dose or addition of an antiepileptic medication. Recognition and treatment of clozapine-related seizures will become increasingly important as its use grows in the 1990s.

Adult↗
PubMed1990

Single- vs multiple-dose pharmacokinetics of clozapine in psychiatric patients.

Clozapine plasma levels were monitored in 16 patients during a series of three consecutive treatments (single dose-multiple dose-single dose). Each patient received a single 75-mg dose (3 x 25 mg) with clozapine tablets, and serial plasma samples were collected over 48 hr after the dose. At 48 hr, a multiple-dose regimen was started, consisting of an initial dose escalation period followed by dosing at a constant regimen for at least 6 days. After the last dose, serial plasma samples were again obtained over 72 hr. Drug was then withheld for at least 7 days, a final single 75-mg dose was given, and plasma sampling was repeated. A subset of the patient population (N = 7) was used to test for a food effect during the single-dose treatments. The pharmacokinetic parameters between the initial and the final single dose periods were not significantly different. Similarly, there were no differences within patients when given the dose after fasting (fed 1 hr after dose) or with a meal. In contrast, the terminal elimination rate differed between the single-dose and the multiple-dose treatments (t1/2 m3 = 7.9 hr single dose and 14.2 hr multiple dose) (P less than 0.05) and the dose-normalized area under the plasma concentration/time curves increased 27% with multiple dosing. Since a previous study in patients (Choc et al., Pharm. Res. 4:402-405, 1987) showed dose proportionality of clozapine plasma concentrations during multiple-dose regimens, the present results cannot be described by Michaelis-Menten kinetics.

Adult↗
PubMed1990

A two-year clinical and economic follow-up of patients on clozapine.

The long-term efficacy of clozapine therapy and its effect on health care costs were examined over a two-year period. Patients on clozapine showed marked clinical improvement as measured by the Brief Psychiatric Rating Scale. They also had significantly lower rates of rehospitalization and hospitalization costs than a comparison group of schizophrenic patients who received standard neuroleptic treatment and who were considerably less psychotic at hospital admission. By the second year of the study, savings on mental health care costs averaged $20,000 for each patient on clozapine therapy. The savings were due largely to the patients' change in residence from costly inpatient facilities to less expensive settings in the community.

Agranulocytosis↗
PubMed1989

Predictors of response to clozapine therapy.

Multiple regression analysis and discriminant function analyses were applied to the question of prediction of therapeutic success or failure to clozapine therapy, using a non-biological predictor pool of 46 items. This effort was not successful, accounting for less than 25% of outcome variance under optimal conditions. However, it does appear that while clozapine efficacy in treatment-resistant schizophrenic patients in general is superior to such neuroleptics as chlorpromazine or haloperidol, the "paranoid" subgroup appears to benefit most.

Clozapine↗
PubMed1988

Clozapine for the treatment-resistant schizophrenic. A double-blind comparison with chlorpromazine.

The treatment of schizophrenic patients who fail to respond to adequate trials of neuroleptics is a major challenge. Clozapine, an atypical antipsychotic drug, has long been of scientific interest, but its clinical development has been delayed because of an associated risk of agranulocytosis. This report describes a multicenter clinical trial to assess clozapine's efficacy in the treatment of patients who are refractory to neuroleptics. DSM-III schizophrenics who had failed to respond to at least three different neuroleptics underwent a prospective, single-blind trial of haloperidol (mean dosage, 61 +/- 14 mg/d) for six weeks. Patients whose condition remained unimproved were then randomly assigned, in a double-blind manner, to clozapine (up to 900 mg/d) or chlorpromazine (up to 1800 mg/d) for six weeks. Two hundred sixty-eight patients were entered in the double-blind comparison. When a priori criteria were used, 30% of the clozapine-treated patients were categorized as responders compared with 4% of chlorpromazine-treated patients. Clozapine produced significantly greater improvement on the Brief Psychiatric Rating Scale, Clinical Global Impression Scale, and Nurses' Observation Scale for Inpatient Evaluation; this improvement included "negative" as well as positive symptom areas. Although no cases of agranulocytosis occurred during this relatively brief study, in our view, the apparently increased comparative risk requires that the use of clozapine be limited to selected treatment-resistant patients.

Adult↗
PubMed1987

Multiple-dose pharmacokinetics of clozapine in patients.

After a 2-day buildup, patients were dosed continuously with clozapine solution at three ascending dose levels (37.5, 75, and 150 mg bid for 7 days at each dose level). Following the morning administration on the twenty-third day of dosing a drug holiday was instituted which lasted for a minimum of 48 hr. Serial plasma samples were obtained during each of the periods and during the drug holiday for the calculation of the steady-state parameters AUCSS, CSSmax, and CSSmin at each dose level as well as for the assessment of the terminal elimination rate. Mean parameter values for AUCSS, CSSmax, and CSSmin showed a linearly increasing response with the dose, well described by a straight line passing through the origin. The terminal elimination appeared to follow linear kinetics and had a mean half-life of 15.8 hr (range, 5.8-33 hr).

Adolescent↗
PubMed1987

The risks and benefits of clozapine versus chlorpromazine.

Clozapine is an atypical antipsychotic drug with reduced risk of unwanted neurological effects in comparison with other drugs. In this multicenter study, 151 hospitalized schizophrenic patients were randomly assigned to treatment under double-blind conditions to assess the antipsychotic efficacy and safety of clozapine versus chlorpromazine. All patients exhibited tardive dyskinesia or other extrapyramidal side effects associated with at least two prior neuroleptics. Eleven patients were dropped from treatment due to extrapyramidal symptoms while being treated with chlorpromazine; only one clozapine patient's treatment was terminated for this reason. Clozapine patients exhibited clinical improvement superior to that of chlorpromazine patients as assessed by the Brief Psychiatric Rating and Clinical Global Impression scales. These results suggest that clozapine is well tolerated and may be therapeutically superior to chlorpromazine in treating psychotic behavior. Agranulocytosis potential can be minimized by frequent white blood cell counts and removing nonresponding patients from treatment prior to the peak risk period (months 2 through 6).

Adult↗