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Biomedical subjects

P J Perry

Publications and source records attributed to P J Perry.

At least 91 records · Page 5Linked to original sources
PubMed1987

Fenfluramine treatment of autism: relationship of treatment response to blood levels of fenfluramine and norfenfluramine.

Nine children meeting DSM-III criteria for infantile autism were treated with fenfluramine hydrochloride or inactive placebo in a double-blind crossover trial that followed the protocol for the fenfluramine multicenter study. Parents of the two children who had had the highest fenfluramine blood levels wished to have their children continue on fenfluramine, although the improvement they saw could not be demonstrated on the various rating instruments employed. The results of the study, while providing minimal support in themselves for the effectiveness of fenfluramine, do raise the possibility that fenfluramine blood levels might be related to treatment response.

Adolescent↗
PubMed1987

The relationship between antidepressant response and tricyclic antidepressant plasma concentrations. A retrospective analysis of the literature using logistic regression analysis.

The relationship between the antidepressant effect of the tricyclic antidepressants and their plasma concentrations was reviewed. Logistic regression was utilised as an analytical tool to facilitate the evaluation. The currently available literature allowed the construction of 4 tricyclic data sets of sufficient size to warrant statistical analysis. Inspection of the distribution of the data and the logistic regression analyses resulted in several conclusions regarding the existence of 'therapeutic windows' for these drugs. Firstly, no relationship between amitriptyline plasma concentrations and therapeutic response was apparent. Secondly, curvilinear relationships were apparent for 2 of the other tricyclic antidepressants studied. The currently recommended therapeutic range of 60 to 150 micrograms/L for nortriptyline was found to be the range most likely to produce a positive antidepressant effect. Desipramine concentrations between 108 and 158 micrograms/L were most commonly associated with beneficial therapeutic responses. Finally, a linear relationship was noted for imipramine in which an imipramine therapeutic plasma concentration threshold of 244 micrograms/L and above was most commonly associated with a beneficial response to the drug.

Animals↗
PubMed1987

Rational use of antidepressants.

The key to the proper treatment of affective illness is a correct diagnosis of the subtype of depressive illness. Thus, primary treatment recommendations include the tricyclic antidepressants for a major depressive episode, electroconvulsive therapy for a major depressive episode with psychotic features, and monoamine oxidase inhibitors for dysthymic disorder and atypical depressive episodes. Nonresponding patients are treated with either lithium augmentation of TCA therapy or ECT. Second-generation antidepressants are recommended in situations where their adverse effect profiles offer significant advantages over TCAs in an individual patient. Maintenance antidepressant treatment may be necessary to prevent recurrent depressive episodes.

Antidepressive Agents↗
PubMed1986

Seizures following the withdrawal of alprazolam.

Seizures were observed following the withdrawal of alprazolam administered in therapeutic dose for 10 weeks. A review of available case reports suggests that seizures, like other withdrawal phenomena, are more apt to occur with short-acting benzodiazepines. To prevent their occurrence these drugs should be discontinued gradually and consideration given to substituting long-acting drugs during the withdrawal period. Physicians should remain alert to the fact that seizures may occur as early as 24 hours after the abrupt withdrawal of short-acting benzodiazepines.

Adult↗
PubMed1986

Effects of smoking on nortriptyline plasma concentrations in depressed patients.

The pharmacokinetic parameters of half-life, volume of distribution, and steady-state nortriptyline plasma concentration normalized to a 100-mg/day maintenance dose were calculated in nine smokers and 15 nonsmokers. The mean normalized total nortriptyline concentration for the smokers of 118 +/- 33 ng/ml was significantly lower than the nonsmokers' mean value of 158 +/- 35 ng/ml. The mean normalized free plasma concentrations for the smokers of 11.4 +/- 3.5 ng/ml was not different from the nonsmokers' mean concentrations of 11.5 +/- 2.6 ng/ml. The smokers had a slightly higher percentage free drug values of 10.2 +/- 4.0% (p = 0.08) as contrasted to 7.4 +/- 1.5% free nortriptyline for the nonsmokers. The nortriptyline half-life figures for both the free and total drug concentrations did not differ. Multiple linear regression analysis utilizing age, smoking status, sex, liver function, and the presence or absence of enzyme-inducing or -inhibiting drugs as the potential independent variables and percentage free nortriptyline or total nortriptyline concentration as the dependent variable, found that smoking status explained 21% of the variation in the percentage free nortriptyline in the patients and 26% of the variation in the total nortriptyline concentrations. These preliminary data suggest that smokers ideally should be dosed at the lower end of the nortriptyline therapeutic range, whereas nonsmokers should be dosed at the upper end to maximize the antidepressant effect and minimize adverse effects.

Adolescent↗
PubMed1986

The utility of a single-point dosing protocol for predicting steady-state lithium levels.

Two methods for predicting steady-state serum lithium level were compared prospectively in in-patients suffering from affective disorder. A single-point prospective administration model that required a single 24-hour serum lithium level, following a test dose produced statistically similar predictions of the observed steady-state lithium levels as did a model that required 12- and 36-hour levels. However, the latter two-point method produced significantly more accurate predictions from clinical interpretation. Although the two-point approach is preferable, the single-point method is clinically acceptable if its limitations of accuracy are taken into consideration.

Adult↗
PubMed1985

Relationship of free nortriptyline levels to therapeutic response.

The relationship between the free plasma concentration of nortriptyline and therapeutic response was examined. Eighteen depressed inpatients were treated for 21 days with steady state total nortriptyline plasma concentrations between 50-150 ng/ml. Steady state free nortriptyline concentrations were measured. The therapeutic nortriptyline response was measured by administering the Hamilton and the Carroll Rating scales at day zero and day 21. Statistical relationships between free levels of drug and clinical response were found to be insignificant. Qualitative assessment of the data suggest that free serum levels of nortriptyline in excess of 10 ng/ml may have an inhibitory effect on clinical response.

Adolescent↗
PubMed1985

Recent psychostimulant use in hospitalized schizophrenics.

The incidence of CNS stimulant use among 300 patients admitted to an acute care psychiatric facility was estimated to be 31% overall; 11% of patients admitted to use within 6 months of the index hospitalization. A number of previously described relationships between stimulant use and schizophrenia were confirmed. Relapsing schizophrenics utilized stimulants prior to hospitalization more often than nonschizophrenic patients; outpatient antipsychotic prophylaxis did not prevent these relapses. It is concluded that stimulants partially contribute to relapse in schizophrenics.

Adult↗
PubMed1985

Theophylline-lithium interaction.

The effect of steady state therapeutic theophylline serum levels on lithium renal clearance was investigated. Group mean lithium renal clearances and serum lithium levels varied in predicted fashion. Individual variability in these parameters was significant. Clinical implications are considered and management suggestions made.

Adult↗
PubMed1984

Theophylline precipitated alterations of lithium clearance.

The effect of steady state therapeutic theophylline serum levels on lithium clearance was investigated. A significant increase in lithium clearance occurred with the administration of theophylline. Despite considerable intersubject variability, a direct lithium clearance estimation method demonstrated a mean increase of 30% with the addition of theophylline. The concomitant use of lithium and theophylline potentially may alter lithium levels sufficiently to result in manic or depressive relapses in patients receiving lithium prophylactically.

Adult↗
PubMed1984

Prospective evaluation of two lithium maintenance dose schedules.

A prospective method for recommending lithium carbonate maintenance doses for patients requiring the drug either prophylactically or for acute mania has been previously described. Of 18 patients who required prophylactic lithium levels between 0.40 and 0.89 mEq/liter, the maintenance dose equation achieved the predefined therapeutic range in 15 (83%) cases. Of 20 patients requiring lithium concentrations between 0.90 and 1.30 mEq/liter for the treatment of acute mania, 17 (85%) attained the therapeutic range after receiving the recommended maintenance dose. The authors discuss the factors that limit the usefulness of this prospective dosing protocol.

Adult↗
PubMed1984

Nortriptyline capacity-limited metabolism: a case report.

A case report of a 62-year-old patient is presented with apparent dose-dependent kinetics for nortriptyline following the administration of therapeutic doses of the drug. Twelve-hour measurements of total plasma nortriptyline following steady state administration of the drug at 10 mg every other day, 10 mg daily, and 25 mg daily were 38, 86, and 647 ng/ml and while free plasma nortriptyline concentrations were 0.37, 0.9, and 6.6 ng/ml, respectively. Half-lives calculated from samples collected at 12, 24, and 36 hours status after administration of steady state 10 mg every other day, 10 mg daily, and 25 mg daily maintenance doses were 30.4, 36.7, and 64 hours, respectively. Toxicity did not occur despite excessive total plasma tricyclic antidepressant concentrations as a result of abnormally increased plasma protein binding of nortriptyline. The case is contrasted to the usual pharmacokinetic characteristics for the tricyclic antidepressants.

Blood Proteins↗
PubMed1983

The impact of psychopharmacology education on prescribing practices.

The authors describe a pharmacology education program on the psychiatry service of a Veterans Administration medical center. The program, directed by a clinical pharmacist, includes weekly lectures to medical students and weekly psychopharmacology review rounds for psychiatric residents that are also attended by staff psychiatrists. To determine the impact of the psychopharmacology review rounds on prescribing practices, the authors conducted a retrospective chart review of psychopharmacologic treatment methods before and after the rounds were instituted. The review compared prescribing practices in the two periods and focused particularly on changes in practices related to multiple daily dosages, polypharmacy, prophylactic anticholinergics, and drug use in alcohol withdrawal. The review demonstrated that the teaching effort resulted in a use of psychotropic medications that was more in line with recommendations in the literature.

Adult↗
PubMed1983

Prediction of lithium maintenance doses using a single point prediction protocol.

Conflicting reports regarding the utility of a previously described single point prediction dosing method for lithium prompted the present study's reexamination of the relationship between a single point lithium concentration and the lithium maintenance dose. Seventeen informed, adult patients with affective illness were studied. The relationship between their 24-hour lithium concentration after a test dose and the maintenance dose was significant, hence confirming earlier reports. In addition, more confident relationships were noted when steady state range concentrations for lithium prophylaxis (0.41 to 0.89 mEq/liter) and for treatment of acute mania (0.9 to 1.27 mEq/liter) were analyzed separately. Maintenance dose predictive equations were generated for these lithium steady state ranges from a 24-hour single point level after a 1200-mg test dose. The clinical usefulness of the new relationships observed for maintenance dose prediction must await prospective testing.

Adult↗
PubMed1982

Treatment of unipolar depression accompanied by delusions. ECT versus tricyclic antidepressant--antipsychotic combinations.

A retrospective chart study conducted to compare the effectiveness of ECT to tricyclic antidepressant--antipsychotic combination therapy in the treatment of psychotic major depressive disorder. A favorable treatment response occurred in 86% of the ECT-treated patients and 42% of the antidepressant--antipsychotic-treated patients. Depressive symptoms showed improvement in all ECT-treated patients but only 50% of the tricyclic antidepressant--antipsychotic-treated patients. It was concluded that a significantly better treatment response can be expected in delusional depressed patients if treated with ECT rather than a tricyclic antidepressant--antipsychotic drug combination.

Adult↗