Evaluation of amitriptyline use for depression when prescribed by internists and psychiatrists

The efforts involved in structuring and implementing a drug utilization review (DUR) program that was designed to assess the use of amitriptyline for depression when prescribed by internists and psychiatrists is described. In-depth audit criteria were used to identify deviations from the criteria for each group. An immediate goal of this amitriptyline DUR program is to apply the results of the study toward the implementation of a targeted, multifaceted educational program. The design of the DUR program should emphasize the individual needs of each of the two study groups.

Tricyclic-induced electroencephalogram abnormalities and plasma drug concentrations

In a double-blind study of 34 randomly assigned depressed inpatients, antidepressant-induced electroencephalogram (EEG) abnormalities were compared in amitriptyline-treated versus bupropion-treated patients. Drug-free baseline EEGs plus one or more repeat EEGs under pharmacokinetic steady state conditions were obtained. Of the 34 patients, eight developed EEG abnormalities. Seven were on amitriptyline and one was on bupropion (chi 2 = 13.77, df = 3, p less than 0.01). All but one of the amitriptyline-treated patients with EEG abnormalities had plasma concentrations above its therapeutic range (150 to 250 ng/ml), whereas all with normal EEGs were within or below this range.

Mania induced by metoclopramide: case report

A case is reported in which a patient became manic while taking metoclopramide, a drug which affects several neurotransmitter systems. The apparent relationship between the manic symptoms and metoclopramide was strengthened by a placebo period with no such symptoms, followed by recurrence upon rechallenge. Amitriptyline blunted the manic response.

The dexamethasone suppression test in hospitalized prepubertal depressed children

The dexamethasone suppression test was performed on 20 hospitalized prepubertal children who met DSM-III criteria for major depressive disorder. Fourteen children (70%) did not suppress cortisol secretion at either 8:00 a.m. or 4:00 p.m. The 4:00 p.m. value alone predicted 93% of the nonsuppressors.

Cerebromicrocirculatory defects in animal model of depression

In the tetrabenazine (TBZ) model of depression, the cerebromicrocirculation was discovered to respond abnormally to metabolic demand as mimicked by the administration of CO2. Altered responsivity of cerebral blood flow and effective permeability of the blood--brain barrier to changes in PaCO2 were found. These physiologic defects coincided temporally with TBZ-induced depletion of central norepinephrine and dopamine and with the development of the behavioral effects of TBZ (the end points used to test the antidepressant potential of experimental drugs). Pretreatment with amitriptyline (a standard antidepressant and amine reuptake inhibitor) prevented the development of these TBZ-induced abnormalities in the cerebromicrocirculation, just as it prevented the behavioral effects.

Evaluation of bupropion hydrochloride: the first of a new class of atypical antidepressants

Bupropion hydrochloride is a new antidepressant that differs clinically and pharmacologically from the tricyclic antidepressants and the monoamine oxidase inhibitors. Pharmacokinetically, bupropion is an intermediate-lived drug with a half-life of about 12 hours. Its antidepressant activity in man has been demonstrated in double-blind, placebo and active drug-controlled studies. Onset of antidepressant action occurs in one to three weeks. Bupropion has a greater effect on the neuronal reuptake of dopamine than of other biogenic amines. At a recommended dose of 450-600 mg/day, the side effect profile of bupropion also distinguishes it from other antidepressants. It does not bind to cholinergic receptors in vitro at clinically relevant concentrations and does not produce appreciable autonomic side effects. The exception is dry mouth, which is reported in 13% of patients. The mechanism underlying this effect is unclear. Bupropion is devoid of cardiovascular effects (e.g., impaired intracardiac conduction, reduced myocardial contractility, decreased peripheral resistance, orthostatic hypotension) in both human and animal studies. The drug is nonsedating and antagonizes the effects of commonly used sedatives, such as alcohol and diazepam. It does not produce weight gain. In susceptible patients, activating effects can occur. Given this profile, bupropion should be less toxic than conventional antidepressants when taken in overdoses; however overdose experience with the drug is limited.

Plasma levels of imipramine and adverse effects in children

In 22 prepubertal depressed children, the total plasma concentration of imipramine and its major metabolite, desipramine, varied by more than sevenfold. The plasma drug concentrations correlated with slowing of intracardiac conduction, elevation of diastolic blood pressure, and increase in heart rate. These drug-induced changes were uniformly observed when the total tricyclic level exceeded 225 ng/ml. However, subjective reporting of nuisance side effects was not related to plasma drug concentration. These findings suggest that children can be safely treated when their plasma levels are below 225 ng/ml. If higher plasma levels are attained, closer monitoring is warranted.

Antidepressant response and plasma concentrations of bupropion

A double-blind multicenter evaluation compared the antidepressant efficacy of bupropion (Wellbutrin) to both placebo and amitriptyline (Elavil, Endep) in adult patients who met DSM-III criteria for major depressive disorder. Steady-state plasma samples were obtained 11-12 hours and 4 hours after the last dose in 50 and 44 patients, respectively, who were treated for 6 weeks with bupropion. There was a curvilinear relationship between antidepressant efficacy and trough plasma bupropion concentrations, with maximum response observed at 5-100 ng/ml and virtually none below 25 ng/ml. The increase in plasma bupropion concentration from the trough level to the 4 hour postdose peak level was also positively related to antidepressant response.

Ethanol effects on brain concentrations of amitriptyline and the relationship to psychomotor function

The effect of amitriptyline (AMI), ethanol (ETOH), and ETOH followed by AMI on both general activity (open field) and motor performance (two rotorod tasks) was tested in reference to a saline-injected control. The combination (ETOH plus AMI) produced greater impairment on all three tasks than did either drug alone. ETOH pretreatment also produced a 223% increase in the total tricyclic antidepressant (TCA) brain concentration. The decrement in motor performance was logarithmically related to total TCA brain concentrations in both animals treated with AMI alone and those pretreated with ETOH prior to AMI. The concentration which consistently produced behavioral impairment was similar to those previously reported to cause cognitive and electroencephalographic dysfunction in humans.

Role of the central adrenergic system in mediating amitriptyline-induced alteration in the mammalian blood-brain barrier in vivo

All tricyclic antidepressants increase the degree of equilibration of [3H]water across the cerebral capillary (Ew) as measured by a dual-label radioactive tracer technique. By using amitriptyline (AMI) as a prototype, a series of studies was conducted to determine the mechanism for this drug effect. The AMI-induced increase in Ew was blocked by 6-hydroxydopamine ablation of central aminergic neurons and by pretreatment with phenoxybenzamine, an alpha adrenergic antagonist. Pretreatment with propranolol, a beta adrenergic antagonist, did not block the AMI-induced increase. Central serotonergic ablation by p-chloroamphetamine had no effect on the AMI-induced increase. Treatment with atropine and hydroxyzine separately also did not alter Ew. Based on these results, the AMI-induced increase in Ew appears to be mediated by the effect of the drug on central adrenergic neurons. The serotonergic, anticholinergic and antihistaminergic actions of AMI, by themselves, do not appear to play a role in this phenomenon. The results are compatible with the concept that the central adrenergic system functions, in part, to regulate the cerebromicrocirculation.

Depression in children: relationship between plasma imipramine levels and response

The effects of imipramine treatment and plasma drug levels were studied in 20 prepubertal children (16 males, 4 females; age range 7-12 years) hospitalized for major depressive disorder (DSM-III criteria). No change in symptomatology was seen after 2 weeks of individual/group/family psychotherapy, but 12 children experienced a remission within 6 weeks of beginning imipramine. Response to the drug was concentration-dependent; of the children who achieved total tricyclic (imipramine plus desipramine) plasma levels of 125-225 ng/ml, 92% responded, compared with 25% of those outside this range. Antidepressant response was correlated both with total tricyclic plasma levels and with plasma desipramine levels (r = 0.72 and 0.56, respectively), but not with plasma levels of imipramine alone.

A dual label radiotracer technique for the simultaneous measurement of cerebral blood flow and the single-transit cerebral extraction of diffusion-limited compounds in rats

An inexpensive method is described which permits simultaneous quantification of the cerebrovascular extraction (E) of diffusion-limited compounds and cerebral blood flow (CBF) in rats. This method involves the use of two radioisotopic tracers: (a) a diffusion-limited, test tracer such as [3H]water; and (b) a reference tracer. The reference tracer is also used in the measurement of CBF. In the development and validation of this technique, results using two different types of reference tracers were compared. The reference tracers employed were: (a) [14C]butanol, a flow-limited (i.e. freely diffusible) compound; and (b) [141Ce]microspheres which embolize in the cerebromicrocirculation. Inclusion of [3H]water in the injection bolus permitted simultaneous measurement of Ew using both butanol and microspheres as the reference as well as concomitant measurement of CBF. Both tracers provided estimates of these values which behaved physiologically with respect to increasing arterial CO2 content (paCO2). In addition, the simultaneous measurement of Ew and CBF permitted calculation of the effective permeability of water across the blood-brain barrier (PwS) which was discovered to increased with increasing paCO2.

Antidepressants alter cerebrovascular permeability and metabolic rate in primates

External detection of the annihilation radiation produced by water labeled with oxygen-15 was used to measure cerebrovascular permeability and cerebral blood flow in six rhesus monkeys. Use of oxygen-15 also permitted assessment of cerebral metabolic rate in two of the monkeys. Amitriptyline produced a dose-dependent, reversible increase in permeability at plasma drug concentrations which are therapeutic for depressed patients. At the same concentrations the drug also produced a 20 to 30 percent reduction in cerebral metabolic rate. At higher doses normal autoregulation of cerebral blood flow was suspended, but responsivity to arterial carbon dioxide was normal.

Tricyclic-antidepressant-induced delirium and plasma drug concentration

Fourteen patients receiving routine doses of amitriptyline developed plasma drug concentrations above 300 ng/ml. Of the 7 patients with plasma levels above 450 ng/ml, 6 developed a drug-induced delirium as opposed to none of the 7 with levels below 450 ng/ml. Thus, this adverse effect could be avoided by monitoring levels and reducing dosage when appropriate.

Toxicity of tricyclic antidepressants--kinetics, mechanism, intervention: a review

Overdoses of tricyclic antidepressants (TCA's) are frequent and can be life-threatening due primarily to their cardiotoxic effects. These overdoses may be intentional, accidental, or even iatrogenic, with the latter due to the wide interindividual variability in elimination rates. Steady-state TCA plasma levels correlate well with tissue concentrations and permit adjustment of dosage to minimize the risk of iatrogenic poisoning. Other factors increasing the risk of toxicity include age, cardiac status, and concomitant use of drugs. Cardiotoxicity results from direct membrane actions of TCA's at high tissue concentration. Treatment of TCA overdose is first aimed at preventing absorption, then at hastening elimination by interfering with the enterohepatic recirculation. Although drugs can ameliorate certain toxic effects, indiscriminate use of purported antidotes can have deleterious results.

An intravenous technique for the measurement of cerebral vascular extraction fraction in the rat

An intravenous injection method to measure cerebral vascular extraction fractions of highly diffusible substances in the rat is described. The brain extraction fractions of 3H-labeled water (Ew) and ethanol (Ee) were defined as the ratio of either of those tracers to the freely diffusible reference tracer, 14C-butanol, in the brain, divided by the ratio of the tracers available for the extraction during the time between simultaneous intravenous injection of the tracers and decapitation of the rat. Ew and Ee were measured in five regions of brain, including brainstem and cerebellum, under PaCO2 conditions ranging from 15 to 85 mm Hg. The extraction fractions for both test tracers were shown to vary with PaCO2-induced flow changes according to the equation, ln(1 - E) = -PS/F. When PS/F values calculated from regional measurements of Ew and Ee were plotted versus PaCO2, least squares regression equations of the plots could be used to compare permeabilities of both tracers at any given PaCO2 value. Ratios of the permeabilities of water and ethanol varied regionally but were relatively constant in a given region under different flow states. This intravenous injection method allows for accurate measurement of the extraction fractions of even highly diffusible tracers under varied flow conditions in all brain regions regardless of arterial blood supply.

A liquid chromatographic method for quantitating amitriptyline in brain tissue

A previously reported method for measuring tricyclic antidepressants (TCA) in plasma was modified to measure TCA, specifically amitriptyline (AMI) and nortriptyline (NOR) in rat brain tissue. Brains obtained from drug-free and AMI-treated rats were extracted and assayed using a Waters high-performance liquid chromatograph. Drug-free brain tissue contained no substances which interfered with the assay of these TCAs. Drug recovery averaged 90 +/- 3.4% (mean +/- SEM). Seven intra-run assays of a spiked brain tissue sample yielded coefficients of variation of 2.7% for AMI and 1.8% for NOR. Seven inter-run assays of the same sample varied 4.2% for AMI and 3.5% for NOR. Five separate assays of a brain homogenate sample spiked with 50 ng/ml of drug yielded values of 50 +/- 2.1 SEM ng/ml for AMI and 54 +/- 1.1 SEM ng/ml for NOR. Standard curves were linear when constructed from samples in a concentration range of 250--3,000 ng/g wet weight tissue (r = 0.96, P less than 0.001).

Brain concentrations of tricyclic antidepressants: single-dose kinetics and relationship to plasma concentrations in chronically dosed rats

A previously reported method of measuring tricyclic antidepressant concentrations in brain tissue and plasma was used to measure amitriptyline (AMI) in rats following drug administration using different routes, doses, and time intervals. In rats given AMI intraperitoneally (IP), brain concentrations increased during the first 30 min after drug administration and then declined. Brain concentrations increased linearly with changes in IP dosage and increased logarithmically with changes in intravenous dosage. No simple relationship existed between brain and plasma concentrations in acutely dosed rats. However, a linear relationship existed between plasma and brain concentrations in chronically treated animals (r = 0.96, P less than 0.001). The brain:plasma drug ratios observed in chronically treated rats corresponded to ratios reported in man. Thus, conclusions drawn from these studies can probably be extrapolated to the clinical situation. Based on our data, the molar concentration of drug achieved on therapeutic doses is 10(-5)--10(-6) M. This information may aid in understanding the clinical relevance of in vitro drug: receptor binding studies which are typically reported in molar concentrations.

Medical therapies for mood disorders alter the blood-brain barrier

The effects of amitriptyline, lithium, and electroconvulsive shock on cerebral permeability and blood flow were tested. These three treatments share in common (i) the ability to influence the functional activity of central adrenergic neurons by way of effects on the release, reuptake, or metabolism of norepinephrine and (ii) therapeutic efficacy in mood disturbances. Under control conditions, cerebral permeability increases linealy with increasing arterial partial pressure of carbon dioxide and hence cerebral blood flow. All three treatments altered this relationship in a manner consistent with their adrenergic effects. Amitriptyline potentiated this increase in cerebral permeability whereas lithium and electroconvulsive shock blunted this phenomenon. These results support the hypothesis that one function of central adrenergic neurons is regulation of the blood-brain barrier and raise the possibility that a related effect may underlie the clinical usefulness of such treatment.

Measurement of cerebral vascular extraction fractions in the rat using intracarotid injection techniques

A small volume (5 microliters) common carotid arterial injection method is described for the quantitation of cerebral vascular extraction fractions (Et) of diffusion limited tracer molecules in the rat. The method is a modification of a technique introduced by Oldendorf and widely used for the study of blood-brain barrier phenomena. While the Oldendorf technique has proven valuable for estimating the relative permeabilities of substances, it is limited in measuring Et under conditions of physiologically or pharmacologically altered permeability or blood flow. The method described in this paper--using a small volume (5 microliters) common carotid injection, a freely diffusible reference tracer, [14C]butanol, and a 5 sec circulation time--allows for measurements of Et that reflect changes in blood flow and small differences in permeability. The modified method is important for the study of the regulation of cerebral vascular permeability and flow in an inexpensive animal model.

Analgesic abuse and the barbiturate abstinence syndrome

Abstinence syndromes secondary to sedative-hypnotic drugs can occur in a wide range of clinical situations. The first such cases due to a combination analgesic product containing a barbiturate are reported. Cryptic abuse of combination prescription drugs can cause difficult diagnostic problems, such as the abstinence syndromes reported here. Each prescriber should know the individual agents contained in a combination preparation and their potential side effects.

The effect of dibenzazepines (tricyclic antidepressants) on cerebral capillary permeability in the rat in vivo

The degree of equilibration of [3H]water across the cerebral capillary was evaluated by measuring its cerebral extraction fraction (Ew) by using a dual label radioactive tracer technique. All tricyclic antidepressants (125 mumol/kg i.p. at 5 min) increased Ew as compared to base line. The rank order of the drugs in producing this response was doxepin greater than amitriptyline greater than imipramine greater than nortriptyline greater than desmethylimipramine greater than protriptyline. The effect of amitriptyline, the prototype tricyclic for this study, was rapid in onset (maximal effect within 5 min), reversible (duration 15 min), dose-dependent and generalized throughout the brain. Amitriptyline also induced a marked increase in the cerebral extraction fraction of [3H]ethanol. A difference in the time course of the drug effect on these two tracers indicated that the elevation in E was due to the increase in cerebral capillary permeability to both polar and lipid soluble substances. This work demonstrates that tricyclic antidepressants have important central effects on non-neuronal tissue.

Long-term antidepressant treatment: alterations in cerebral capillary permeability

Chronic treatment of rats with amitriptyline (AMI) induced a persistent increase in the diffusibility of water into the brain (EW). This effect was observable 12 h after the last dose. AMI induces this alteration at plasma drug concentrations of 71 +/- 13 ng/ml (the therapeutic range for man is 100--250 ng/ml). Furthermore, chronic treatment potentiated the increase observed after acute drug administration and resulted in a 350% enhancement in the permeability of water across the cerebral capillary. Thus, long-term antidepressant administration can chronically influence cerebral function by affecting capillary permeability.

Prospective use of saliva lithium determinations to monitor lithium therapy

A mathematical equation (y = 2.27x -0.45) relating saliva (y) to plasma (x) lithium concentrations was previously determined by one of the authors. A prospective study is reported here in which the correlation coefficient between the predicted and the observed plasma concentrations in a new group of 25 patients was r = 0.89 (p less than 0.001). The study demonstrates that saliva lithium determinations can be safely used to monitor lithium therapy.

Progressive multifocal leukoencephalopathy: cerebral mass lesions

In 9% of reported cases, progressive multifocal leukoencephalopathy presents clinically and radiographically as a focal cerebral mass lesion. Initial misdiagnosis may occur, leading to surgery for suspected malignancies. The electroencephalographic, radiologic, and histopathologic findings in such cases are discussed.

The effect of tricyclic antidepressants on cerebral fluid dynamics

Tricyclic antidepressants are thought to act primarily via effects on adrenergic neurotransmitters. Recent research supports the concept that a major function of the central adrenergic system is the modulation of cerebral fluid dynamics. Based on this concept, studies in the rat were conducted to assess the effects of these drugs on cerebral capillary permeability and flow by quantitating changes in the extraction fraction of water (Ew). Amitriptyline and nortriptyline produced significant increased in Ew for the total forebrain (from control values of 0.67 to experimental values as high as 0.99) while protriptyline had no effect on Ew. The amitriptyline-induced increase in Ew occurred at doses which produced plasma levels (500 ng/ml) near the range defined as therapeutic in depression studies. The magnitude of the effect was similar for both amitriptyline and nortriptyline representing a 35--40% increase over control values. The effects were uniformly observed throughout the forebrain: rostral telencephalon, caudal telencephalon, and diencephalon.

Use of saliva lithium determinations for monitoring lithium therapy

During acute and chronic administrations of lithium, 25 patients were studied to determine the effect of other psychotropic drugs on the plasma-saliva lithium concentration correlations. Changes, even discontinuation, in either tricyclic antidepressants or neuroleptics did not affect the plasma-saliva ratio which had an overall correlation coefficient of r = 0.79 (p less than 0.01). The relationship using linear regression analysis was described by the equation, y = 2.27x--0.45. Individual patients' plasma-salivary relations were described by this equation in 87% of cases. The study extends the usefulness of these determinations to include patients on lithium and neuroleptics or tricyclic antidepressants.

Dosage schedule and plasma levels of doxepin and desmethyldoxepin

Plasma levels of doxepin and its metabolite desmethyldoxepin were determined in 7 depressed patients treated with doxepin hydrochloride in 3 divided doses at 1000, 1600, and 2200 hours (t.i.d.), and repeated after changing the dosage schedule to a single daily bedtime (h.s.) dose at 2200 hours. Doxepin and its metabolite were measured at 9000, 1200, 1500, and 1800 hours. None of the individual patients showed clinically significant changes in their plasma concentration of tricyclic antidepressant on the 2 dosage schedules. No difference in the clinical condition of the patients was detected on the 2 dosage schedules using the Zung Self Rating Depression Scale, however patients experienced more morning sedation while on the single h.s. dosage. This study provides pharmacological support for the prescription of doxepin on a once daily basis.

Imipramine and desipramine plasma levels: relationship to dosage schedule and sampling time

Tricyclic antidepressant plasma levels were determined after administration if imipramine (11 patients) and desipramine (ten patients) as a single daily bedtime dose or in divided doses. Plasma levels of the tricyclics were relatively stable on both dosage schedules due to the long plasma half-lives of these drugs. No difference was found between the two dosage schedules and the therapeutic effectiveness or the severity of side effects. The majority of patients preferred the single dose schedule. These findings support the use of a single daily dose of imipramine and desipramine.

Pseudohypoparathyroidism and Capgras syndrome

The patient described in this report is the second case in which the Capgras syndrome has occurred in association with pseudohypoparathyroidism (Hay et al, 1974). Her admission was for evaluation and treatment of psychosis, but after detailed metabolic and psychometric testing it was established that pseudohypoparathyroidism and cerebral dysfunction were antecedent conditions. In view of recent reports in the literature, the significance of these conditions in the pathogenesis of the Capgras syndrome will be discussed.

Benzodiazepines and withdrawal psychosis. Report of three cases

Three cases of acute psychotic illness following sudden withdrawal from high daily doses of benzodiazepines were associated with agitation and confusion. Disorientation was prominent in two of the patients. None of the patients had had previous psychotic episodes. The condition of all patients was reversed dramatically with hypnotic drugs. Gradual withdrawal was successfully accomplished without relapse, with a follow-up of as much as one year. To our knowledge, this is the first such series in the literature.

Bilateral altitudinal anopia caused by infarction of the calcarine cortex

The patient reported here had a bilateral inferior altitudinal hemianopia from lesions of the calcarine (striate) cortex of the occipital lobes. The only significant pathologic findings were bilateral calcarine artery occlusive disease, with infarcts of the striate cortex on both sides. The ages of the infarcts appeared compatible with the clinical development of the respective visual field defects. The rest of the visual system was anatomically intact.

Virus-cell interaction in oligodendroglia, astroglia and phagocyte in progressive multifocal leukoencephalopathy. An electron microscopic study

A 46-year-old female, with an 11 year history of malignant lymphoreticular disease, developed a neurological illness clinically manifested by a focal mass lesion in the left frontal lobe. In biopsied tissue, immunofluorescence study revealed the presence of JC antigen in the glial cells. Histologically, the lesion was characteristic of PML consisting of PML consisting of focal necrosis in the subcortical white matter, numerous fat laden macrophages and marked hypertrophy of oligodendrocytes and astrocytes. By electron microscopy, hypertrophic astrocytes contained intranuclear viral particles consistent with papova virions and aggregates of intracytoplasmic viral particles consisting of a single to several virions tightly surrounded by a single membrane. The membrane appeared to have been derived from that of the cellular vesicles. Fusion of the virus-associated membrane to the astroglial plasmalemma occurred when the virions appeared to shift towards extracellular space. The virioncontaining astrocytes showed cytoplasmic "fibrillar hypertrophy" similar to the characteristic gigantic astroglias of PML. This fact would provide an additional evidence that these gigantic cells, although lacking identifiable viral structures, were the result of anaplastic transformation by JC virus. Many virus-bearing astroglias were noted to be in the early stage of cellular necrosis, of "edematous degeneration". This further indicates that the JC virus is capable of inducing both lytic and abortive astroglial infections. Many oligodendroglias were hypertrophic due to the presence of intranuclear viral particles and markedly increased numbers of microtubules and free ribosomes in the cytoplasm. Membrane-bound intracytoplasmic viral particles were also noted in the oligodendroglias. Some fat laden macrophages contained large intracytoplasmic viral bodies, presumably originating from phagocytized virus-bearing cells.