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Biomedical subjects

L Bertilsson

Publications and source records attributed to L Bertilsson.

At least 181 records · Page 10Linked to original sources
PubMed1985

Alaproclate a novel antidepressant? A biochemical and clinical comparison with zimeldine.

Clinical and biochemical effects of two selective 5-HT uptake inhibitors, zimeldine and alaproclate, were studied in 24 hospitalized patients with endogenous depression. According to a randomized parallel group design 14 patients were treated with zimeldine and 10 with alaproclate. The dosage of both zimeldine and alaproclate was 200 mg daily. For the evaluation of the clinical effect, Montgomery & Asberg Depression Rating Scale (MADRS) was used. Seven of 14 patients treated with zimeldine and seven of 10 treated with alaproclate improved. 5-HT uptake inhibition in patients' platelets and concentration of amine metabolites (5-HIAA, HVA, HMPG) in CSF were studied before and during treatment. After 3 weeks of treatment with zimeldine 5-HIAA and HMPG in CSF decreased significantly while HVA in CSF increased significantly. Zimeldine produced a significant 5-HT uptake inhibition in platelets. During treatment with alaproclate no significant change in amine metabolites concentration in CSF was found and there were no mean changes on 5-HT uptake inhibition in platelets.

Adult↗
PubMed1984

Weak binding of 10-hydroxymetabolites of nortriptyline to rat brain muscarinic acetylcholine receptors.

The relative affinities of nortriptyline (NT) and its 10-hydroxymetabolites to rat brain muscarinic acetylcholine receptors have been determined by competition with 3H-quinuclidinyl benzilate binding. It is shown that the major NT metabolite, E-10-OH-NT, has only 1/18 the affinity of NT for the muscarinic receptor. Since this metabolite is equipotent to NT in inhibiting neuronal noradrenaline uptake, it is suggested that it might be of clinical value as an antidepressant by virtue of having less anticholinergic side-effects than NT itself.

Amitriptyline↗
PubMed1984

Potent therapeutic effect of carbamazepine-10,11-epoxide in trigeminal neuralgia.

The clinical effects of carbamazepine-10,11-epoxide were assessed in six patients with trigeminal neuralgia. The patients were first given an optimal therapeutic dose of carbamazepine. Part of or the entire carbamazepine dose was then exchanged for the metabolite carbamazepine-10,11-epoxide for three to six days. The patients were unaware of changes in the therapeutic regimen (single-blind). Carbamazepine dosages ranged from 400 to 1,400 mg/day and carbamazepine-10,11-epoxide dosages ranged from 300 to 1,000 mg/day. The clinical effects were assessed by the patients' recordings of pain attacks. When carbamazepine-10,11-epoxide and carbamazepine were given in similar doses, the pain control was comparable. On a plasma concentration basis, carbamazepine-10,11-epoxide had a considerably higher pain-relieving potency than carbamazepine. During carbamazepine treatment, the epoxide metabolite contributes to the antineuralgic effect to an extent that might be comparable to that of the parent drug. No side effects were seen during carbamazepine-10,11-epoxide therapy.

Aged↗
PubMed1984

Theophylline metabolism in relation to antipyrine, debrisoquine, and sparteine metabolism.

Theophylline plasma clearance (Clp) and clearance to its metabolites ( Clm ), as well as antipyrine saliva clearance ( Clsal ) and its Clm were compared in a crossover study in 25 healthy subjects. They were selected with regard to smoking status (nine smokers, 16 nonsmokers) and oxidation phenotype of debrisoquine and sparteine (six poor metabolizers [PMs] and 19 extensive metabolizers [EMs]). Clm of theophylline (1,3-dimethyluric acid, 1-methyluric acid, and 3-methylxanthine) correlated (r greater than or equal to 0.92) to each other and to total theophylline Clp (r greater than or equal to 0.97). Smokers had higher Clm to all metabolites, particularly by the N-demethylation pathways. After correction for the effect of smoking, there was no difference between EMs and PMs with regard to theophylline Clp or Clm . Antipyrine clearances by EMs and PMs ( Clsal and Clm of 4-OH-antipyrine, 3-OH- methylantipyrine , or norantipyrine) also did not differ. Antipyrine Clsal and Clm correlated to theophylline Clp (r between 0.50 and 0.69). It is concluded that theophylline metabolism (N-demethylations and C-oxidation) is not under the same genetic control as sparteine and debrisoquine oxidations, and that there may be a partial overlap in factors that regulate the metabolism of theophylline and antipyrine.

Adult↗
PubMed1984

Nortriptyline and debrisoquine hydroxylations in Ghanaian and Swedish subjects.

Eleven Ghanaian and 12 Swedish subjects phenotyped with a debrisoquine (D) hydroxylation test were given a single oral dose of nortriptyline (NT). Much the same percentage of the given NT dose was excreted as 10-hydroxy-NT (10-OH-NT) by Ghanaians (43.1%) and Swedes (49.2%). There was a close correlation between plasma clearance of NT by 10-hydroxylation and the D metabolic ratio (D/4-OH-D in urine) in the Ghanaians (rs = -0.95; P less than 0.01) and Swedes (rs = -0.84; P less than 0.01). The E-isomer of 10-OH-NT is the major isomer in both Ghanaians (76% to 92% of total 10-OH-NT) and Swedes (78% to 95%). It is suggested that the E-10-hydroxylation of NT and the 4-hydroxylation of D are similarly coregulated in Ghanaians and Swedes.

Administration, Oral↗
PubMed1984

CSF monoamine metabolites in melancholia.

The neurotransmitter metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 4-hydroxy-3-methoxyphenyl glycol (HMPG) in cerebrospinal fluid (CSF) were measured by mass fragmentography in 83 patients with melancholia (diagnosed by the Newcastle Inventory and the Research Diagnostic Criteria), and 66 healthy volunteer controls. After adjustment by analysis of covariance for differences between the subject groups in body height, age and sex distribution, significantly (P less than 0.001) lower concentrations of 5-HIAA and HVA were found in the melancholia patients than in the controls. HMPG did not differ between the groups. The differences could not be accounted for by differences in timing or examination techniques, and not by previously administered drugs (all patients were drug-free at the examination, but a minority had taken small amounts of psychotropic drugs prior to the wash-out period). The differences persisted after excluding the suicidal patients. There were no clear-cut differences between unipolar and bipolar patients. It is suggested that the reduced concentrations of 5-HIAA and HVA in the melancholic patients may be due to altered serotonin and/or dopamine functions in the central nervous system, which may be connected with an increased vulnerability to certain types of affective illness.

Adult↗
PubMed1984

CSF monoamine metabolites of depressed patients during illness and after recovery.

Repeated lumbar punctures in 16 healthy volunteers showed reproducible concentrations of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF). In seven depressed patients, studied during two or three illness periods, the metabolite concentrations were also fairly stable. In 11 patients CSF concentrations of 5-HIAA, but not of HVA, were higher after recovery than during depression. This increase of 5-HIAA after recovery was confined to patients whose initial serotonin metabolite levels were low. The finding constitutes further evidence of a biochemical heterogeneity within the depressive disorders, and suggests that patients whose CSF 5-HIAA is low during a depressive episode may have a less stable serotonin system than other patients with depressive illness.

Adult↗
PubMed1984

Clinical pharmacology of antidepressant drugs: pharmacogenetics.

There are marked interindividual differences in Css of tricyclic antidepressants. These are due mainly to corresponding differences in the rate of elimination of the drugs and hence in drug oxidation. Twin, family, and cross-over studies with NT and DMI show that their kinetics (Css, Kel, and Vd) are controlled mainly by genetic factors (in drug-free individuals). Slow hydroxylators are at risk of developing excessive plasma concentrations of NT and DMI when given per se or when formed from the tertiary amines AT and imipramine. Classic antidepressants have fairly well established concentration-effect curves in endogenous depression. Severe toxicity usually occurs at supratherapeutic plasma levels and might be prevented by tailoring the dosage according to the individual's drug hydroxylating capacity. Monitoring drug plasma levels is particularly relevant in slow hydroxylators. There is a strong association between an individual's ability to hydroxylate NT and DMI and his D hydroxylation phenotype. The ratios between D and 4-OH-D in urine after a single oral dose are bimodally distributed in the population (polymorphism), with 3 to 10% being slow hydroxylators and the remainder rapid hydroxylators. Indices of NT-hydroxylation do not sharply distinguish the two phenotypes. The D metabolic index will predict the patient's capacity to hydroxylate NT and DMI and hence Css during therapy. Possibly similar hydroxylases are involved in the 4-hydroxylation of debrisoquine, in the stereospecific E-10-hydroxylation of NT, and in the 2-hydroxylation of DMI. By contrast demethylation of AT (and probably other tertiary tricyclics) does not significantly correlate to debrisoquine hydroxylation. The increasing knowledge of the clinical pharmacokinetics of tricyclic antidepressants is a distinct advantage over that of the new generation of antidepressants, where little is known about concentration-effect relationships and factors governing their rate of metabolism.

Adolescent↗
PubMed1983

Amitriptyline metabolism: relationship to polymorphic debrisoquine hydroxylation.

Amitriptyline AT demethylation to nortriptyline NT was determined in nine healthy subjects who had been phenotyped with respect to debrisoquine D hydroxylation capacity. AT demethylation was calculated from the ratio between the plasma AUCs of NT after single oral doses of AT and NT. Plasma clearance of AT by demethylation did not correlate with the ratio between D and 4-hydroxy-D in urine (rs = -0.55).

Adult↗
PubMed1983

Single-dose kinetics and metabolism of carbamazepine-10,11-epoxide.

Carbamazepine-(CBZ)-10,11-epoxide (CBZ-E) was found to decompose in gastric juice in vitro. An antacid did not affect the bioavailability of single CBZ doses given to three subjects and was therefore used to neutralize gastric juice when administering CBZ-E. CBZ-E was given orally as a suspension in two single doses ranging from 10 to 200 mg to each of four healthy subjects. Plasma concentrations of CBZ and CBZ-E were determined with high-performance liquid chromatography. Plasma concentrations and urinary excretion of the end metabolite trans-10,11-dihydroxy-10,11-dihydro-CBZ (trans-CBZ-diol) were measured by mass fragmentography. After dosing with CBZ-E, peak plasma concentrations of the parent compound were reached within 2 hr. Urinary recovery of trans-CBZ-diol was 90 +/- 11% (mean +/- SD) of the dose, indicating almost complete absorption. Plasma kinetics of the epoxide fitted an open one-compartment model with elimination half-lifes (t 1/2s) of 6.1 +/- 0.9 hr. Clearance was 89 +/- 25 ml x kg-1 x hr-1. The urinary excretion t 1/2 of the trans-CBZ-diol was 12.4 +/- 0.9 hr, which is longer (P less than 0.001) than the epoxide plasma t 1/2. There was no indication of dose-dependent kinetics of the epoxide. After 200 mg CBZ to the same subjects, plasma CBZ t 1/2 was 26.0 +/- 4.6 hr and clearance was 23.4 +/- 4.6 ml x kg -1 x hr -1. Of the CBZ dose, 20.5 +/- 2.9% was excreted as the trans-CBZ-diol, which gives an estimate of the percentage of CBZ that is metabolized by the epoxide-diol pathway in healthy subjects. These observations provide a basis for the administration of CBZ-E in patients to assess its clinical effects.

Absorption↗
PubMed1983

Antipyrine metabolism in relation to polymorphic oxidations of sparteine and debrisoquine.

Thirty-five healthy subjects who had been classified as extensive or poor metabolizers of both sparteine and debrisoquine were given a single oral dose of antipyrine. Saliva concentration of antipyrine and urinary excretion of its three major oxidation metabolites were measured. All the parameters of antipyrine metabolism which were estimated had similar distributions in both the 28 EM and 7 PM genetic phenotypes defined by the metabolism of sparteine and debrisoquine. The clearance of antipyrine by the formation of 4-hydroxy-antipyrine and 3-hydroxy-antipyrine respectively were closely correlated (r = 0.83, P less than 0.001) and both were significantly higher in smokers than in non-smokers. Demethylation of antipyrine also seemed to be influenced by smoking, but not to a statistically significant extent. These findings confirm the influence of the environmental factor of smoking in antipyrine oxidative biotransformations.

Adult↗
PubMed1982

Gradients of monoamine metabolites and cortisol in cerebrospinal fluid of psychiatric patients and healthy controls.

Amine metabolites and cortisol were measured in four consecutive 3 ml samples of lumbar cerebrospinal fluid (CSF). There were pronounced concentration gradients for both 5-hydroxyindoleacetic acid and homovanillic acid, and there was no difference in the gradients of 11 controls and 17 psychiatric patients (10 depressed). As there was a close correlation between the mean of the first two fractions and the mean of all four fractions, a concentration obtained in 6 ml can be used to calculate that in a 12 ml CSF sample. In psychiatric patients there was a slight, but statistically significant concentration gradient for 3-methoxy-4-hydroxyphenylglycol (unconjugated as well as conjugated). No gradient was found for cortisol in CSF.

Body Height↗
PubMed1982

Nortriptyline formation after single oral and intramuscular doses of amitriptyline.

Oral (50 mg) and intramuscular (25 mg) amitriptyline (AT) was given to six normal subjects and the area under the plasma concentration-time curve (AUC) for nortriptyline (NT) formed was calculated. There was no difference between the AUCs (corrected for dose) after the two routes of administration. The ratio between the AUCs (corrected for dose) after the two routes of administration. The ratio between AUCoral and AUCim averaged 0.95 (range 0.69 to 1.13). After intramuscular AT maximum NT plasma concentration was reached after 24 to 48 hr, whereas it was 8 to 24 after oral dosing.

Administration, Oral↗