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Therapeutic drug monitoring (TDM) of tricyclic antidepressants (TCA) is established in the treatment of depression to optimize outcome and safety. However, there are few reports on TDM under naturalistic clinical conditions. In the present study, we investigated a TDM group (TDM) and a randomly assigned parallel group without TDM (no-TDM) while on TCA treatment. Serum levels were analyzed in both cohorts, but feedback and dose recommendation were only provided for the TDM group. Serum levels of TCA were assessed by high-performance liquid chromatography (HPLC). The outcome was measured weekly using the Hamilton Depression Rating Scale (HAMD), the Clinical Global Impressions Scale (CGI), and the UKU side-effect scale. 84 patients with depressive disorder according to DSM-IV were recruited in three centers (TDM, n = 43; no-TDM, n = 41; mean age 49.9 +/- 13.2 years, 63.1 % female). Patients were treated with either amitriptyline (n = 69) or doxepin (n = 15); the mean dosage at endpoint was 126 +/- 35 mg and 155 +/- 47 mg, respectively. The mean study duration was 21 +/- 8 days. Both groups improved according to HAMD (from 25.2 +/- 8.4 at baseline to 12.0 +/- 7.4 at endpoint) and CGI scores (68 % responders). Moderately severe or severe side effects occurred in 16 % of patients. Adequate dose adjustment was significantly higher in the TDM group (60 % vs. 46 %, p < 0.05); this led to a significantly higher rate of therapeutic serum levels in the TDM group (58 % vs. 44 %, p < 0.05). Direct effects of TDM were not found for effectiveness. Therapeutic TCA serum levels over weeks one to three, however, were associated with significantly better outcome at endpoint (p < 0.05) as measured with changes in the HAMD or CGI response rates from baseline to endpoint. Finally, considerable side effects occurred significantly more often when serum levels were above the therapeutic range (27 % vs. 11 %; p < 0.01). We conclude that treating depression with TCA can be optimized by early TDM, which is superior to clinical judgment on its own. Since the psychiatrists in charge were less than completely "compliant" to the recommendations provided together with serum levels, the effect could be more pronounced than this study shows. The results encourage further studies in order to optimize antidepressant pharmacotherapy when using TDM appropriately.

Unlabelled: 34 patients with diagnosis of depressive episode (ICD-10) were treated for 8 weeks with tricyclic antidepressants (TCA) 22 patients were treated with clomipramine 75-175 mg daily, 11 with imipramine 75-150 mg and 1 with amitriptyline 150 mg. Following parameters were analysed: plasma concentration (FPIA, HPLC), pharmaco-EEG (spectrum power for delta, theta, alfa1, 2, beta 1, 2, 3 by the use of FFT), clinical improvement (HAMD, HARS, SGI, SERS). 50% reduction in HAMD was regarded as improvement., Results: No relationship between mental state and plasma concentration of TCA was found, initial results in SERS were prognostic for the course of treatment, pharmaco-EEG was typical for antidepressants after two weeks of treatment and reflects clinical improvement and stabilization of plasma concentration. Comparing the plasma concentration of TCA measured by the use of FPIA and HPLC method may be useful for the implementation of monitoring therapy.

In a prospective, open clinical study, the relationship between serum levels of amitriptyline (At) and nortriptyline (Nt) and the therapeutic effect after 6 weeks of treatment was investigated. Serum levels were measured by gas-liquid chromatography and the therapeutic effect was assessed by the Hamilton Depression Rating Scale (HAMD) and the Clinical Global Impression Scale (CGI). A number of 25 non-delusional, moderate to severely depressed inpatients were included. A therapeutic window relationship was detected by means of regression analysis (quadratic model). Low and high serum levels were associated with low therapeutic effect. In an intermediate range, the probability of good therapeutic effect was increased. This relationship reached significance for the serum levels of At (p < 0.05) and a trend for the sum of serum levels of At and Nt (p < 0.1). As expressed by the regression coefficient r2, about 25% to 35% of the variability of therapeutic effect was explained by serum levels. Dichotomized data sets according to limits of final values of HAMD and CGI as well as limits of a therapeutic window of 70 ng/ml and 200 ng/ml (sum of At and Nt) revealed significant differences by means of Fisher's exact test (p < 0.05). Furthermore, increased ratios of serum level of Nt per serum level of At were found to be associated with decreased therapeutic effect. Thus, the present data support the existence of a therapeutic window of serum levels of At in depression. Also taking into account other reports, this therapeutic window can be defined as being between about 70 and 220 ng/ml. The assay of serum levels of At can be used to lower the risk of unsatisfactory therapeutic outcome.

Modern pharmacotherapy is based on precise adjustment of a dosage schedule to individual requirements of patient. Therapeutic drug monitoring is a method that allows for a more effective treatment approach, especially in the case of a narrow therapeutic index of a drug. Tricyclic antidepressant drugs are characterised by narrow therapeutic index as well as relationship between serum drug concentration and side effects. It was demonstrated that interindividual variability of blood concentrations of tricyclic antidepressant drugs is related to genetic polymorphism of oxidating enzymes participating in metabolism of these drugs. The aim of the study was to estimate the impact of therapeutic drug monitoring of tricyclic antidepressant drugs as well as genotyping on efficacy and safety of endogenous depression therapy. The study included 9 patients with established diagnosis of endogenous depression. Blood serum concentrations of amitryptyline was measured by fluorescence polarisation immune assay (FPIA, Abbott system). Genotype of cytochrome P450 isoenzyme CYP2D6 was determined using PCR-RFLP method. It was demonstrated that monitoring therapy of tricyclic antidepressant drugs in combination with determination of the genotype seems to be more safe and effective. Monitoring therapy and genotyping may be less expensive than the costs of prolonged hospitalisation and risk of side effects.

The clinical significance of monitoring the plasma levels of amitriptyline and its metabolites in prediction of the clinical outcome of depressive episode was investigated in 49 inpatients. Discriminant analysis of drug concentrations (at two weeks after initiation of drug treatment) and clinical outcome revealed that increasing the plasma levels of amitriptyline, cis-isomers of hydroxylated metabolites (Z-10-hydroxyamitriptyline and Z-10-hydroxynortriptyline) predicted a better clinical outcome, while increasing of plasma levels of nortriptyline and trans-isomers of hydroxylated metabolites (E-10-hydroxyamitriptyline and E-10-hydroxynortriptyline) were shown to predict a poor clinical outcome in the depressive episode of the subjects, and that clinical outcome of approximately 73% of the subjects could be correctly predicted.

Although many attempts have been made, to date no convincing evidence exists of a relationship between plasma concentrations of amitriptyline (AT), its active metabolite nortriptyline (NT) and clinical response. Fifteen patients with primary depression (according to DSM-IV) were divided in two groups according to given doses: (I) 6 patients received 3 x 50 mg of AT daily; and (II) 9 patients received 3 x 25 mg of AT daily, for 6 weeks. The clinical status was determined with Hamilton Depression Rating Scale. Both investigated doses were therapeutically effective. AT and NT plasma concentrations were assayed by high performance liquid chromatography. Following administration of 3 x 50 mg of AT daily, the correlation of concentrations of AT, NT, total AT + NT and clinical response were rAT = -0.702 (P < 0.1), rNT = -0.761 (P < 0.1), rAT + NT = -0.741 (P < 0.1). The linear and very high correlation were also present with concentrations of AT, NT, total AT + NT and clinical response in depressive patients on 3 x 25 mg AT daily: rAT = -0.785 (P < 0.02), rNT = -0.811 (P < 0.01), rAT + NT = -0.848 (P < 0.01). Our results support a high correlation between AT/NT plasma concentrations and clinical response indicating that therapeutic monitoring of AT and its metabolite, NT, can provide eventual clinical response.

Nonresponse to tricyclic antidepressant (TCA) treatment is observed in about one-third of depressed patients. The cause(s) for nonresponse - apart from disease-specific effects - might be the failure to build up sufficiently high serum TCA levels due to noncompliance, substance abuse, rapid metabolism, or low dose. We carried out a retrospective analysis relating antidepressant serum levels to patient data obtained in the naturalistic setting of the Psychiatric Hospital of the Bonn University during the introductory phase of drug-monitoring. Case reports of 110 depressed inpatients who were treated with amitriptyline or doxepin were analyzed with respect to the following: medication and comedication, daily dose, type and duration of treatment, serum TCA concentrations (analyzed by the fluorescence polarization immunoassay), age, sex, body weight, abuse of nicotine or alcohol intake, serum transaminases (ALT, alanine aminotransferase, and AST, aspartate amino transferase), gamma-glutamyltranspeptidase (gamma-GT) and creatinine, compliance, and response. The salient findings were: 1. Serum TCA concentrations increased linearly with the daily amitriptyline dose but not with that of doxepin. 2. Interindividually, there was an eight to ten-fold difference in serum TCA concentrations at steady-state with 150 mg/day of either drug; longitudinally, we observed intraindividually a coefficient of variation of 8% and 12% for amitriptyline and doxepin respectively. 3. With amitriptyline (150 mg/day), the correlation between age and serum TCA concentrations was low (r = 0.33, p < 0.055) and no correlation was found after the administration of doxepin (150 mg/day), nor was there any correlation between age and dose-adjusted serum TCA concentrations after the administration of either drug. 4. Nonresponders had significantly lower serum levels than responders. These results suggest that patients should not qualify as nonresponders unless it can be demonstrated (and it is clinically applicable) that the steady-state serum TCA levels are stable within the upper limit of the recommended therapeutic range and serum level.

Steady-state plasma levels of mianserin, amitriptyline, and nortriptyline were determined by HPLC in two groups of elderly depressed patients who underwent a 5-week treatment with mianserin (60 mg/day in three oral doses) or amitriptyline (75 mg/day in three oral doses). Both treatments proved to be effective in reducing depressive symptoms. In the mianserin group, responder patients had steady-state plasma concentrations of mianserin higher than nonresponders. No relationship was found between amitriptyline, nortriptyline, or amitriptyline+nortriptyline plasma levels and clinical response in amitriptyline treated patients.

Electroencephalograms recorded before and after 4 weeks treatment of depressed patients with fluoxetine or amitriptyline were assessed visually and by power spectrum analysis blind to patient, treatment and whether the recordings were carried out before or after treatment. No significant between-group differences in alpha, beta or theta activity were found on visual assessment. Power spectrum analysis revealed a significant decrease in the amount of beta activity at week 4. There was no EEG evidence of drowsiness or epileptiform activity in either of the treatment groups.

The serum concentrations of amitriptyline and its 3 metabolites--nortriptyline, 10-hydroxy-amitriptyline and 10-hydroxy-nortriptyline were determined in 18 depressive patients treated with amitriptyline for 6 weeks. The relationships between the serum concentrations and the clinical effects were statistically analyzed and showed significant correlations. The authors suggest that the total TAD serum concentration (280 ng/ml) can be used as the index for clinical efficacy, so far as the above data are concerned.

Background: This study identifies eight patients who during routine therapy with conventional doses of tricyclic antidepressants (TCAs) experienced elevated plasma concentrations and suffered a grand mal seizure. We correlate the incidence of TCA-induced seizures with TCA plasma level and suggest that the incidence of TCA-induced seizures can be significantly reduced with the judicious use of therapeutic drug monitoring., Method: Seven of the eight cases of TCA-induced seizures during routine pharmacotherapy represent all the cases known to the authors during their careers. Histories were evaluated for factors that would predispose patients to suffer seizures. The following data were also recorded: (1) duration of treatment with the dose that was associated with the seizure, (2) the time between last dose and the seizure, (3) a plasma TCA level obtained at the time of seizure, and (4) presence or absence of other manifestations of TCA toxicity. In addition, a MEDLINE search was conducted using the key phrases "tricyclic antidepressants" and "seizures" to obtain all English language articles published since 1966 on the occurrence of TCA-induced seizures., Results: The mean +/- SD daily TCA dose was 250 +/- 80 mg/day. The mean +/- SD total plasma TCA concentration was 734 +/- 249 ng/mL (range, 438-1200 ng/mL). The only risk factor that emerged for experiencing seizures was an elevated plasma TCA concentration. Three patients presented with no other manifestations of TCA toxicity prior to seizure., Conclusion: The incidence of TCA-induced seizures for our inpatient population in which therapeutic drug monitoring is routinely used is 0.4%. This incidence is less than that reported in earlier inpatient series (1% to 4%). Our finding is consistent with the conclusion that therapeutic drug monitoring reduces the incidence of TCA-induced seizures by allowing for rational dose adjustment.

Monitored treatment of a depressed phase of unipolar affective disorder was conducted in 11 female patients receiving imipramine and in 12 females taking amitriptyline. Patients were randomly assigned to one of the drug and in 6 patients the drugs were switched because of the lack of response to the first used compound. In the imipramine treated group a satisfactory response after 4 weeks of management (less than 6 points on Hamilton's depression scale) was observed in 6 patients and in amitriptyline treated group in 5 patients. Patients displaying a satisfactory response to amitryptyline had significantly higher--as compared to remaining patients in the group--plasma levels of the drug after two and four weeks of treatment. Such an association was not observed in patients treated wtih imipramine. Severity of depression and motor retardation before the treatment was similar both in patients with satisfactory and with poor response to imipramine as well as to amitriptyline. However the intensity of anxiety symptoms was higher in patients exhibiting poor response to treatment with amitriptyline and imipramine as well.

57 patients treated with amitriptyline because of depressive syndrome in the course of affective disorder were studied. The drug level in plasma was measured weakly using a gas chromatograph. A non-linear correlation between the amitriptyline level in plasma and the clinical effect of the treatment was substantiated. The range of therapeutic effectiveness was determined between 68.0 and 185.0 ng/ml.

Fifty-nine depressed female inpatients were treated with 100 mg amitriptyline (AMT) IM for 4 weeks. Depression ratings and determinations of the parent drug and nortriptyline (NT) were performed weekly. No direct relationship between plasma AMT + NT concentrations and therapeutic response was apparent, but beneficial therapeutic responses and significantly lower side-effect scores were more frequently noted in subjects with concentrations in the 100-200 ng/ml range. AMT + NT concentrations were significantly correlated with age. No significant difference was found in the number of responders between younger and older subjects with two clinical improvement criteria; however, a significant difference emerged when a third more restrictive clinical outcome criterion was adopted. The implications of the present findings for patient treatment and for the interpretation of previous studies are discussed. The data collected point to a possible usefulness of monitoring AMT and NT plasma levels, even if further investigations are needed.

The apparent resistance to tricyclic antidepressant treatment of many depressed patients often may be a result of an inadequate therapeutic trial. Several potentially important variables which may contribute to apparent treatment resistance are discussed, including interpatient pharmacokinetic variability, noncompliance, and inadequate duration of treatment. The current status of the relationship of clinical response and plasma levels of tricyclics and the use of therapeutic blood monitoring to reduce the failure rate in tricyclic antidepressant treatment are also discussed.

Amitriptyline (AT) and the noradrenaline reuptake inhibiting antidepressant oxaprotiline (OT = hydroxymaprotiline) were compared in 59 primary depressive inpatients in a 4-week double blind parallel group design. In the Hamilton Depression Rating Scale and 2 self-rating scales AT proved to be more efficient than OT, mainly with respect to disturbances of appetite and sleep. Agitated patients receiving OT needed more additional tranquilizing medication. The number of side-effects did not differ. Both drugs increased heart rate and skin resistance level (SRL) to about the same degree and did not influence the number of spontaneous fluctuations of SRL, habituation of SRL orienting responses (OR), frequencies of respiration and blinking. Salivation was temporarily more impaired by AT. All physiological variables differed between patients and 30 healthy controls during the whole 4-week trial. Clinical outcome showed a linear relation to OT plasma levels. For AT a therapeutic window was confirmed for concentrations of AT and its metabolite nortriptyline between 125 and 200 ng/ml. Patients whose SRL-OR habituated rapidly had a better outcome than slow habituators. Urinary excretion of 3-methoxy-4-hydroxyphenylglycol was lower in patients than in controls but could not predict outcome with either drug.

Thirty-eight depressed female inpatients, treated intramuscularly with 100 mg/day amitriptyline (AMT), were monitored to investigate the relationships between plasma levels of the drug and its metabolite nortriptyline (NT), the urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG), side effects and clinical response. Considering the whole group, the clinical improvement was better within an intermediate range of AMT plus NT plasma concentrations (100-200 ng/ml). A more favorable outcome was also observed at NT plasma levels below 55 ng/ml. No significantly different percent clinical response among the patient clinical subgroups was observed as well as no significant correlations between MHPG decrease and drug plasma levels.

1. Noradrenaline plasma levels and cardiovascular function modifications with orthostatic challenge during therapy were studied in 59 female depressed inpatients treated with 100 mg amitriptyline daily by intramuscular route for 4 weeks. 2. Therapy induced an increase in pulse rate in supine and upright positions, a decrease of noradrenaline levels and modified standing systolic and (partially) diastolic blood pressure, particularly in elderly subjects. 3. No correlation between neurotransmitter or functional changes and drug plasma levels was noted. 4. The supposed lower noradrenergic output together with blood pressure drop in both positions suggests a reduced sympathetic tone.

Twenty-nine inpatients with primary affective disorder were treated with 150 mg amitriptyline (AT) daily for 28 days. Pretreatment urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was measured in two or three 24-h urine samples. Plasma levels of AT and nortriptyline (NT) were determined after 14, 21, and 28 days of treatment. MHPG excretion was significantly correlated with clinical response to treatment. Responders defined by two different methods showed higher pretreatment MHPG excretion than nonresponders. Correspondingly, high MHPG excretors (median split) showed significantly more improvement than low excretors. These relationships were even more apparent when possibly incomplete urine samples (creatinine excretion below 1000 mg/24h) were excluded. The high and low MHPG subgroups did not significantly differ from each other in their plasma levels of AT, NT, or AT plus NT. A significant rank correlation between clinical response and plasma levels of AT and/or NT did not exist, but there was a trend towards lower levels in responders.

Paroxetine is a new antidepressant drug with potent serotonin (5HT) uptake inhibitory properties. In this double-blind comparative study, the antidepressant effect of paroxetine and amitriptyline has been compared in 44 patients with depressive illnesses of an endogenous nature. Each drug was given for 6 weeks. The 17-item Hamilton Depression Scale was used to measure the antidepressant effect. Reported events were assessed applying a 22-item check list. Non-parametric statistical analyses were applied in the evaluation of treatment outcome for the 30 patients who completed the study. The results showed no significant differences in overall antidepressant efficacy between paroxetine and amitriptyline and that paroxetine displayed significantly fewer instances of dry mouth and orthostatic dizziness than amitriptyline. No obvious relationship was demonstrated between the plasma levels of the drugs and their clinical effects.

Amitriptyline and nortriptyline plasma levels were measured in depressed outpatients 24 hours after a single dose of amitriptyline and following chronic dosing to steady state. Plasma levels of amitriptyline and nortriptyline measured after the single dose correlated highly with steady state plasma levels. Full use as a test to rapidly place patients on a "therapeutic" dosage of drug will need to await a clear delineation of the relationship between blood levels and clinical response for amitriptyline.

In a study of 99 patients receiving amitriptyline or nortriptyline alone and 60 patients receiving one of these antidepressants in combination with perphenazine, the patients receiving the combination medication had up to 70% higher antidepressant plasma levels than patients receiving the antidepressant alone. The groups did not differ significantly in sex, age, smoking behavior, or antidepressant dose level. Due to the possibility of side effects from such combination medication, the authors recommend that depressed patients not responding to the tertiary amine tricyclic antidepressants receive a trial of high doses of the drugs before antidepressant-neuroleptic combinations are administered.

To assess prospectively the predictability of therapeutic dosage based on tricyclic antidepressant (TCA) concentrations after a single dose, 30 subjects were given amitriptyline. In the first 11 subjects maintained on a fixed amitriptyline dose regimen, predictive capacities of 18- and 24-hr single-dose levels were assessed and confirmed in relation to steady-state levels. For the other 19 subjects, the dose that would achieve a therapeutic steady-state concentration of 200 ng/ml was predicted from the 18-hr single-dose level and was rapidly instituted. Subjects achieved a mean steady-state TCA level of 204 ng/ml, with approximately 90% of the levels falling within the therapeutic range. There was clinical improvement within 2 wk in 84% of the subjects. Our results suggest that dose prediction based on TCA levels after a single dose is reliable and useful.

To compare the electrocardiographic effects of therapeutic doses of desipramine and amitriptyline, weekly electrocardiograms (ECGs) were obtained from 46 depressed outpatients treated blindly for 3 weeks to a maximum of 200 mg/day. There was no difference in mean weekly plasma tricyclic antidepressant levels achieved for the two drugs. Compared to baseline measures, treatment with both drugs was associated with an increase in heart rate and a reduction in T wave amplitude, whereas prolongation of the QRS and QTc intervals was significant only for desipramine patients. Comparisons between drugs revealed a greater prolongation of QRS interval duration with desipramine treatment. Changes in ECG measures were not correlated with plasma tricyclic antidepressant levels. The absence of QRS interval prolongation among amitriptyline patients is additional evidence for the importance of distinguishing between the ECG effects of therapeutic and toxic doses of the tricyclic antidepressant.

Serum levels of amitriptyline plus nortriptyline were measured by radioimmunoassay at 1 and 6 weeks in depressed out-patients treated with amitriptyline for 6 weeks. Serum concentrations at 6 weeks were higher in older patients. Serum levels showed no relationship to clinical response at 6 weeks, and a week inverse relationship with response at 2 weeks. Routine monitoring of serum levels appears to be of little value in depressed out-patients treated with amitriptyline.

The authors treated 18 rigorously diagnosed depressed patients with amitriptyline after baseline urine samples were collected for the measurement of 3-methoxy-4-hydroxphenylglycol (MHPG). Neither age nor severity of depression before treatment correlated with MHPG excretion. There was also no significant correlation between baseline MHPG excretion and clinical response at the end of at least 25 days' treatment with amitriptyline. The authors discuss the relevance of amitriptyline and nortriptyline plasma levels to MHPG and the noradrenergic/serotonergic theories of depression.

Amoxapine, a new antidepressant of the dibenzoxazepine class, was compared with amitriptyline in 80 patients with primary unipolar depressive disorders. In a four-week double-blind trial, the two medications were equally effective and had similar onsets of therapeutic action. The range of side effects was similar, although there was a trend for fewer side effects in the amoxapine group. Serum levels were not related to therapeutic response for either medication.

The treatment of depressed patients with a fixed dose of amitriptyline is compared to treatment with an individualized dose calculated by means of a simple pharmacokinetic test. Clinical response and the development of side-effects are compared between the two groups of patients. Although the numbers in the groups were small, the clinical results lend little support to the concept of a therapeutic range of plasma drug concentrations for amitriptyline, and none of the plasma concentrations was high enough to produce serious toxic effects. No obvious clinical advantage was observed in the predicted dose treatment group as assessed by a reduction in depression ratings. The dose prediction test did however more than halve the variance in blood drug concentrations, and its usefulness in preventing high and potentially toxic concentrations is indisputable.

Six women and 6 men who were treated in double-blind fashion major depressive illness did not respond to imipramine or amitriptyline, 150-300 mg/day, during periods of 26-112 days. After the addition of 25 micrograms/day (10 patients) or 50 micrograms/day (2 patients) of L-triiodothyronine (T3), 9 patients showed statistically significant improvement in depression scores; in 8 patients the response was marked. Improvement generally began within 1-3 days and was noted in all aspects of the depressive syndrome; side effects were minimal. T3 did not change plasma levels of imipramine or desipramine or their ratio but did suppress serum thyroxine.

Conflicting results on the correlation of tricyclic levels in plasma and saliva have raised doubts about the clinical usefulness of monitoring these drugs in the latter body fluid. However, saliva drug levels may reflect the free plasma concentration, which possibly determines its level in the brain. In two groups of depressive patients, the evolution was studied of the levels of amitriptyline and nortriptyline in plasma (as free and total) and in saliva, after the administration of amitriptyline. The results show a poor correlation between total plasma and saliva concentration of amitriptyline and nortriptyline, respectively. Levels of both tricyclics in saliva exceed by far those measured in plasma dialysate. However, the relationship is such that free plasma concentrations may be predicted from those measured in saliva, if one takes into account saliva pH at the moment of collecting the sample.

In the course of a double-blind study, 29 depressed patients received amitriptyline 150 mg/day for 4 weeks. Scores on the Hamilton Depression Rating Scale were assessed before treatment and after 2 and 4 weeks, and plasma levels of amitriptyline, nortriptyline, and (E)-10-hydroxynortriptyline were monitored weekly. Response reflected by percent reduction of Hamilton Depression Rating Scale score and by final score was better at steady-state amitriptyline + nortriptyline concentrations of 125-210 ng/ml than at lower and higher plasma levels. This applied to the total group and to the subgroup of 22 female patients. The data confirm the results of a previous study performed in the same hospital. An influence of the (E)-10-hydroxynortriptyline concentration in plasma on therapeutic outcome was not discernible. The results suggest that plasma level monitoring may be helpful when patients do not respond to conventional amitriptyline doses.

A simultaneous analytical method was reported for measuring the plasma levels of amitriptyline, imipramine, clomipramine, maprotiline, nortriptyline, desipramine, desmethylclomipramine, desmethylmaprotiline and amoxapine by high performance liquid chromatography (HPLC). The total plasma levels of each parent drug plus its desmethyl metabolite were monitored in 29 depressed patients administered with amitriptyline, maprotiline or amoxapine using the present analytical method. There were significant linear correlations between the dose per kg body weight and the total plasma levels with amitriptyline and maprotiline, but no such correlation was found with amoxapine. The ratios of total plasma levels to dose per kg body weight of these three drugs were lower in outpatients than in inpatients. These results indicate that the monitoring of plasma levels of antidepressants is useful in treating depression.

Plasma drug concentrations and clinical response were measured in two groups of hospitalised depressed patients, who received amitriptyline or imipramine double-blind, in a dosage of 250 mg for four weeks. Virtually no significant linear or curvilinear relationships were found between any plasma measure and any measure of clinical response. Modest but significant direct relationships were found between age and concentration of parent drugs but not demethylated metabolites. Blood drug level measurement therefore appears to be of little value in monitoring drug treatment of depressed in-patients.

Thirty-five delusional depressed patients were treated for either 28 or 35 days with amitriptyline. The 12 responders could not be differentiated from the nonresponders on a variety of demographic and clinical characteristics. Patients with amitriptyline+nortriptyline plasma levels above 250 ng/ml were significantly more likely to be responders than were patients with levels below that value (p less than .05). A review of the relevant literature revealed that, although some delusional depressives do respond to treatment with tricyclic antidepressants, the presence of delusions is a predictor of poor response to tricyclic antidepressants.

The major sleep characteristics of depression are summarized and new EEG sleep studies of antidepressants, including preliminary data on desipramine and zimelidine, are described. The relationship of steady-state plasma amitriptyline levels to REM sleep and the use of EEG sleep measures as predictors of clinical response to tricyclics will also be discussed. The effects of antidepressant agents on sleep are immediate and pronounced, and studies of these drug-induced effects may also represent a rational method for drug classification.

In 27 inpatients with primary affective disorder the urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was measured prior to a 4-week treatment with 150 mg amitriptyline (AT)/day. Ratings according to the Hamilton depression scale were performed before therapy and repeated after 2 and 4 weeks. Plasma levels of AT, nortriptyline (NT), and E-10-hydroxynortriptyline (OHNT) were assayed weekly, and binding of AT to plasma proteins was determined in one sample. Better therapeutic results were obtained at intermediate, as compared to low and high concentrations of AT or AT plus NT. Independent evaluation of AT and metabolite levels revealed that patients with AT of 50--125 ng/ml responded particularly well when NT did not exceed 95 ng/ml or when NT plus OHNT was below 150 ng/ml. Outside this "therapeutic window' the outcome was markedly poorer. Interindividual variation of AT binding was much smaller than variation of total concentrations. Evaluation of free, instead of total levels did not help to clarify the relationship between clinical and pharmacokinetic variables. Plasma levels within the optimal ranges were found in more patients with high than with low MHPG excretion. The free fraction of OHNT in plasma of healthy subjects was about 35%.

In an attempt to find diagnostic predictors of treatment response, 45 inpatients with major depression in a randomized trial received amitriptyline or imipramine for 23 days after a washout period of 16 days. A polydiagnostic approach was applied to the classification of endogenous depression. Only a minority of diagnostic schedules for endogenous depression proved predictive of a more favorable course during antidepressant treatment: the criteria of D. F. Klein, the Newcastle Scale II, and the Vienna Research Criteria. The symptoms of nonreactivity of mood and diurnal variation were the only endogenous symptoms with predictive ability. In addition, psychotic features and secondary depression predicted an unfavorable course, whereas characteristics of previous course (bipolarity, recurrence) were not predictive.

Fluoxetine, a specific serotonin reuptake inhibitor, was compared to amitriptyline in the treatment of 51 outpatients with primary major depressive disorder. After a 1-week placebo washout, patients were randomly assigned to 5 weeks of treatment with fluoxetine or amitriptyline. Fluoxetine was found to have a therapeutic effect comparable to that of amitriptyline; however, the fluoxetine treatment group had a better Efficacy Index-Side Effects rating and a lower incidence of anticholinergic autonomic side effects. Four amitriptyline-treated patients had to discontinue the study because of serious side effects, while in the fluoxetine treatment group there were no terminations due to side effects. The amitriptyline-treated patients gained significantly more weight than the fluoxetine-treated patients.

A case of altered kinetics of amitriptyline in a patient with porto-caval anastomosis and liver cirrhosis who showed an unusually strong sedative response to the drug, is presented. Therapy with tricyclic antidepressants should be initiated with lower doses and adjusted by plasma level monitoring in patients with liver by-pass.

The practical utilization of clinical pharmacokinetics data are fundamentally different for benzodiazepines and antidepressants. This difference is a consequence of the difference in time-course of action of the two types of drugs. The anxiolytic, sedative or hypnotic effect of benzodiazepines is usually immediate, and the dose can be titrated on the basis of effect measurements. Pharmacokinetic data on benzodiazepines thus in particular are important for design of dose, dose intervals and prediction (warning) about possible accumulation after repeated doses. Different benzodiazepines differ in pharmacokinetic properties, and the clinician should be aware of these differences in order to select the proper drug for a given purpose. Antidepressants are characterized by exerting their effect gradually ovec weeks. It has been shown that the therapeutic effect is related to the steady state plasma concentration which may vary considerably among patients on a standard dose. A major significance of pharmacokinetics of antidepressants thus is, that therapy guided by monitoring of plasma levels of active compounds will improve both safety and efficacy of the treatment. For antidepressants and for benzodiazepines knowledge of the pharmacokinetics is the basis of designing rational dose schedules that take influencing factors such as age, disease, concurrent treatment, etc. into account.