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Open study of low-dose amitriptyline in the treatment of patients with idiopathic fecal incontinence.

INTRODUCTION: Amitriptyline, a tricyclic antidepressant agent with anticholinergic and serotoninergic properties has been used empirically in the treatment of idiopathic fecal incontinence with good results. METHODS: An open study was conducted to test the response to amitriptyline 20 mg daily for four weeks by 18 patients (2 males) of median age 66 years with idiopathic fecal incontinence Incontinence scores, number of bowel movements, computerized ambulatory anorectal pressures, and pudendal nerve terminal motor latencies were evaluated before and after four weeks of therapy. Twenty-four control subjects (10 males) of median age 61 years were also assessed RESULTS: Amitriptyline improved incontinence scores (median pretreatment score = 16 vs. median posttreatment score = 3; P < 0.001) and reduced the number of bowel movements per day (P < 0.001). Amitriptyline also decreased the frequency (median pretreatment frequency = 4.5 per hour vs. median immediate posttreatment frequency = 1.2 per hour (P < 0.05); control median frequency = 0.3 per hour) and the amplitude of rectal motor complexes (median pretreatment rectal pressure = 94 cm H2O vs. median immediate posttreatment rectal pressure = 58 cm H2O (P < 0.05); control median rectal pressure = 36 cm H2O) and improved anal pressures during these events (P < 0.001). CONCLUSIONS: Amitriptyline improved symptoms in 89 percent of patients with fecal incontinence. The data support that the major change with amitriptyline is a decrease in the amplitude and frequency of rectal motor complexes. The second conclusion is that drug increases colonic transit time and leads to the formation of a firmer stool that is passed less frequently. These in combination may be the source of the improvement in continence.

Administration, Oral↗

A comparison of moclobemide, amitriptyline and placebo in depression: a Canadian multicentre study.

In a 7-week prospective multicentre study, the efficacy, tolerability and safety of moclobemide were compared to those of amitriptyline and placebo in parallel groups of out-patients (n = 173) fulfilling the DSM III-R criteria for a major depressive episode. Participants were required to have a minimum baseline total score of 18 on the 17-item Hamilton Depression Rating Scale (HAMD). After a 1-week placebo washout, patients were randomly allocated to the three treatment groups. Assessment of efficacy, as judged by the number of responders achieving a 50% reduction in HAMD score by the end of treatment, showed that both moclobemide and amitriptyline were significantly superior to placebo, but that they were not significantly different from each other. Both treatments differed significantly from placebo with respect to the Physician's Global Assessment of Efficacy ('very good' or 'good' response: moclobemide 57%, amitriptyline 60% and placebo 35%). Assessment of tolerance as judged by the spontaneous reporting of adverse events showed a significant superiority of moclobemide over amitriptyline, but there was no significant difference between moclobemide and placebo. At termination of the study, amitriptyline patients showed a significant elevation of heart rate both supine (10.8 beats/min) and standing (15.5 beats/min), as well as significant weight gain (1.7 kg), but no changes were seen in the moclobemide or placebo groups. In conclusion, both moclobemide and amitriptyline were found to be more effective than placebo in the treatment of depression, while moclobemide had fewer side effects.

Adult↗

The effects of amitriptyline, citalopram and reboxetine on autonomic nervous system. A randomised placebo-controlled study on healthy volunteers.

RATIONALE: In therapeutic use, amitriptyline, reboxetine and citalopram have all been associated with apparent anticholinergic-like side effects (dry mouth, constipation, etc.), despite the very low antimuscarinic activity of reboxetine and citalopram in vitro. OBJECTIVES: We hypothesised that the spectral analysis of heart rate variability (HRV) might detect differences between amitriptyline, citalopram and reboxetine in their anticholinergic activities following a single peroral administration. METHODS: In this double-blind, cross-over study, amitriptyline (75 mg), citalopram (20 mg), reboxetine (4 mg) and placebo were randomly given at 1-week intervals to eight healthy male volunteers. Drug and catecholamine concentrations in plasma were determined repeatedly. The drug effect was assessed with periodic recordings of electrocardiogram (ECG) and blood pressure, and with measurements of salivary secretion. The ECG recordings were subjected to spectral analysis of HRV, in which the high frequency (HF) power of R-R interval (RRI) variability was supposed to reflect cardiac parasympathetic tone. RESULTS: Reboxetine increased heart rate and blood pressure and reduced the HF power of RRI and 3,4-dihydroxyphenylglycol (DHPG) plasma concentrations. Amitriptyline diminished salivary secretion and had a prominent sedative action. Measurements after citalopram did not differ significantly from placebo. CONCLUSIONS: Reboxetine, despite its low antimuscarinic activity in vitro, had distinct effects on the HF power of RRI, consistent with anticholinergic activity in vivo. Amitriptyline had a measurable anticholinergic effect in the salivary glands, but, surprisingly, not in the heart. We suggest that the sedative effect of amitriptyline could alter cardiac sympathovagal balance and, therefore, counteract the anticholinergic drug effect.

Adolescent↗

Challenging the neuronal MIBG uptake by pharmacological intervention: effect of a single dose of oral amitriptyline on regional cardiac MIBG uptake.

PURPOSE: Imaging with metaiodobenzylguanidine (MIBG) is used for the assessment of neuronal dysfunction in various cardiovascular disorders. Although valuable information is obtained by resting MIBG imaging, it is conceivable that competitive interference with the re-uptake mechanism would exaggerate MIBG defects and might unmask subclinical neuronal dysfunction. Tricyclic antidepressants, such as amitriptyline, have been reported to significantly increase cardiac MIBG washout and inhibit uptake into presynaptic neurons. This study was undertaken to assess whether a single oral dose of amitriptyline could influence cardiac MIBG distribution. METHODS: Six patients (aged 62-81 years; four males, two females) who had demonstrated a normal cardiac MIBG scan during work-up for movement disorders were studied. The patients underwent a second 123I-MIBG study after oral administration of 25 mg amitriptyline within 1 week. Single-photon emission computed tomography images were acquired at 4 h to assess the regional distribution of MIBG, after generation of polar maps and employing a 20-segment model. Mean percentage of peak activity was calculated for each segment at rest and after amitriptyline administration. RESULTS: After amitriptyline administration, there was a decrease in regional MIBG uptake in 10+/-4 segments per patient [62/120 segments (52%): 37 segments with a 5-10% decrease, 25 segments with a >10% decrease]. This change was statistically significant in lateral (P=0.003), apical (P<0.0001) and inferior (P=0.03) regions. CONCLUSION: A single oral dose of amitriptyline can induce changes in the uptake and retention of cardiac MIBG, indicating the feasibility of use of pharmacological intervention in cardiac neurotransmission imaging.

3-Iodobenzylguanidine↗

Combination of tizanidine and amitriptyline in the prophylaxis of chronic tension-type headache: evaluation of efficacy and impact on quality of life.

Chronic tension type headache (CTTH) has a strong impact on the Quality Of Life (QOL). We carried out an open-label randomized clinical trial on 18 patients with CTTH in order to compare two different regimens of pharmacological prophylaxis: the first provided for the use of amitriptyline 20 mg/d during 3 months, while in the second we combined amitriptyline with tizanidine (4 mg/d) in the first 3 weeks of treatment. Our hypothesis is that the combination therapy may guarantee an improvement of QOL even in the early stages of treatment. In fact, it's as well-known, there is a delay of 2-3 weeks in the prophylactic effect of amitriptyline, with a consequent persistence, in the first phases of therapy, of the headache and its negative impact. We assessed the following outcome measures: frequency, pain intensity, duration of headache and the Headache Impact Test (HIT) score, used as headache-related QOL measure. The combination therapy was effective since the first month of treatment, with a significant reduction of the headache, greater than one obtained with amitriptyline alone, in terms of frequency (-52.3% vs. -40.7%), intensity (-59.51% vs. -20.39%) and duration (-53.17% vs. -36.16%). This trend was confirmed by the HIT. Our data suggest that the combination of tizanidine with amitriptyline is faster than the amitriptyline alone in providing an improvement in the headache pattern and correlated QOL.

Adult↗

Amitriptyline-induced morphological alterations of the rat blood-brain barrier.

Amitriptyline is known to increase the permeability of the blood-brain barrier but the morphological basis of this increase has not been studied. As catecholamines can influence pinocytosis in dog peripheral blood vessels, the effect of amitriptyline on the pinocytotic activity of blood brain microvessels was studied. Amitriptyline, 34 mg.kg-1 i.p., was injected to rats and the parietal cortex of control and treated animals was prepared for ultrastructural study. Pinocytotic vesicles in endothelial cells were quantified. Amitriptyline significantly increased the density of pinocytotic vesicles in capillary endothelial cells. No other morphological changes occurred after amitriptyline treatment. We conclude that the increase in blood-brain barrier permeability due to amitriptyline may be ascribed at least in part to an increase of pinocytotic activity in brain capillary endothelial cells.

Amitriptyline↗

Inhibitory effects of amitriptyline on the stimulation-induced Ca2+ increase in parotid acini.

The present study demonstrates the effects of the antidepressant, amitriptyline, and the acetylcholine antagonist, atropine, on the stimulation-induced rise in cytosolic, free Ca2+ (Cai2+). The changes in Cai2+ of collagenase-isolated rat parotid acini were measured by means of the Ca2(+)-sensitive dye, fura-2. It was found that stimulation by carbachol resulted in a maximal increase of 582 +/- 34 nM (mean +/- S.E.) in Cai2+ with a ks of 5.8 +/- 1.3 microM. Adrenaline caused a rise of 380 +/- 22 nM in Cai2+ with a ks of 0.5 +/- 0.2 microM. Amitriptyline and atropine were found to inhibit the carbachol-induced rise in Cai2+ with dissociation constants (kI) of 105 and 1.25 nM, respectively, in the absence of agonist. The adrenergic-induced rise in Cai2+ was inhibited by amitriptyline with a kI of 45 nM. Amitriptyline was found to inhibit both receptor classes by a competitive or mixed type of inhibition. Similarly, atropine exerted the same type of inhibition on the acetylcholine receptor. Amitriptyline and atropine were found to be mutually exclusive for competing for substrate binding on the receptor. These findings are consistent with a common binding site for amitriptyline and atropine on the acetylcholine receptor, possibly in close proximity with, but different from the substrate binding site. The stimulation-induced cell shrinkage evoked by the loss of electrolytes and water from the acini was measured by a 90 degree light scattering signal. It was found that this method makes possible the detection of autonomic side-effects of antidepressants on acini suspended in protein-containing media.

Amitriptyline↗

Monoamine metabolites in cerebrospinal fluid of depressed patients during treatment with mianserin or amitriptyline.

A group of 20 inpatients with moderate to severe primary affective disorder received 14 days of placebo treatment and were then randomly allocated to receive mianserin 10 mg 3 times daily or identical amitriptyline 25 mg 3 times daily for 1 week followed by 60 mg mianserin or 150 mg amitriptyline daily for a second week. Patients were rated for side-effects and depression (Hamilton Depression Scale) on days 0, 7, 14, 21 and 28. Probenecid 100 mg/kg was administered in 3 divided doses on days 13/14 and on days 27/28 of the trial, followed by collection of CSF. Blood samples for determination of antidepressant levels were collected on day 27. Both mianserin and amitriptyline produced a significant decrease in CSF levels of 3-methoxy-4-hydroxyphenylglycol (MHPG), but only amitriptyline significantly lowered CSF levels of 5-hydroxyindole-3-acetic acid (5-HIAA). Neither drug affected CSF levels of homovanillic acid (HVA). Both mianserin and amitriptyline produced significant but indistinguishable improvement in mean Hamilton scores over 2 weeks of treatment. There was no relationship between therapeutic response and either plasma antidepressant levels or pre-treatment CSF monoamine metabolite levels in his small group of patients. The reductions of CSF levels of metabolites of NA (MHPG) and 5-HT (5-HIAA) are consistent with the known effects of amitriptyline on amine uptake. Mianserin may reduce CSF MHPG levels as a result of its effects upon NA release and/or uptake, but it appears to be devoid of influence upon central 5-HT metabolism.

Adult↗

Comparison of adinazolam, amitriptyline, and placebo in the treatment of melancholic depression.

Adinazolam, a triazolobenzodiazepine, was compared with amitriptyline and placebo in a double-blind protocol involving melancholic depressives. Forty-eight patients entered the study, and 35 completed 6 weeks of evaluation. Patients were well matched in each of the groups. Initially, the adinazolam group showed more improvement than the placebo group, but this trend did not persist beyond day 7. The amitriptyline group tended to show more improvement than either the placebo or adinazolam groups, and final scores were significantly better for amitriptyline. Depressive symptoms in the amitriptyline dropout group appeared improved, whereas in the adinazolam and placebo dropout groups they were unchanged or worse. Both amitriptyline and adinazolam were more frequently associated with complaints of side effects than placebo. Thus, amitriptyline was observed to be superior to adinazolam and placebo in improvement in depressive symptoms while adinazolam had only a brief early advantage over placebo.

Adolescent↗

Amitriptyline selectively disrupts verbal recall from secondary memory of the normal aged.

Amitriptyline, a frequently prescribed tricyclic antidepressant, is reported to produce an age-related impairment in anterograde memory. However, the locus of this adverse effect has never been described within the context of contemporary learning and memory theory. Fifteen normal elderly subjects were treated with 50 mg amitriptyline and placebo in a cross-over study. A computerized stage analysis of memory revealed that sensory and primary memory were not affected while verbal recall from secondary memory was markedly disrupted by amitriptyline. Further examination of secondary memory revealed that amitriptyline impaired recall, but not recognition. The profile of anterograde memory impairments observed with amitriptyline is similar to that previously reported for the antimuscarinic, scopolamine. Since amitriptyline at the dose employed in this study would be expected to exert marked central antimuscarinic effects, it appears likely that it is the pharmacologic blockade of central muscarinic receptors in the aged that results in the selective disruption of verbal recall in secondary memory.

Aged↗

The analgesic effect of amitriptyline on chronic facial pain.

The efficacy of amitriptyline was evaluated in 28 patients with chronic oral-facial pain. Most of the patients had evidence of musculoskeletal pain while some had a history suggesting pain of neurogenic origin. Two patients had mixed elements of neurogenic and musculoskeletal pain. Amitriptyline was more effective than placebo in reducing pain after 4 weeks of treatment. No effect was found after only 1 week of drug administration in either dose range. When the patients were divided into depressed and non-depressed groups based on their Hamilton depression scores, amitriptyline reduced pain in the depressed and in the non-depressed groups as compared to placebo. Amitriptyline reduced the depression scores in the depressed group but had no effect on the depression scores in the non-depressed group. Thus, pain reduction was not associated with a change in mood in the non-depressed group. Amitriptyline had no effect on patients' ratings of the intensity of experimental heat stimuli. We conclude that amitriptyline is effective in the treatment of chronic oral-facial pain and that its efficacy is independent of its effects on depression. It appears that tricyclic antidepressants act in a fashion different from opiate drugs that alter the sensory discriminative component of pain.

Adult↗

High-affinity nicotinic acetylcholine receptors are required for antidepressant effects of amitriptyline on behavior and hippocampal cell proliferation.

BACKGROUND: A wide variety of antidepressants act as noncompetitive antagonists of nicotinic acetylcholine receptors (nAChRs), but the relationship between this antagonism and the therapeutic effects of antidepressants is unknown. METHODS: Antidepressant properties of the noncompetitive nAChR antagonist mecamylamine in the forced swim test were tested alone and in combination with the tricyclic antidepressant amitriptyline. Mice lacking high-affinity nAChRs were tested in three behavioral models to determine whether these receptors are required for behavioral effects of amitriptyline in common models of antidepressant action. Finally, the brains of wild-type and knockout animals treated with amitriptyline were examined to determine whether high-affinity nAChRs are required for antidepressant-induced increases in hippocampal cell proliferation. RESULTS: Inhibition of nAChRs by mecamylamine had antidepressant-like effects in the forced swim test and potentiated the antidepressant activity of amitriptyline when the two drugs were used in combination. Mice lacking high-affinity nAChRs showed no behavioral response to amitriptyline. Finally, after chronic treatment with amitriptyline, nAChR knockout mice did not show the increase in hippocampal cell proliferation seen in wild-type mice. CONCLUSIONS: These data support the hypothesis that antagonism of nAChRs is an essential component of the therapeutic action of antidepressants.

Amitriptyline↗

Oral bioavailability and intestinal secretion of amitriptyline: Role of P-glycoprotein?

The aim of the study was to evaluate the influence of quinidine, a P-glycoprotein inhibitor, on oral bioavailability and on intestinal secretion of amitriptyline, a tricyclic antidepressant. Amitriptyline was administrated intravenously (5 mg/kg) and orally (50 mg/kg) to rabbits, with and without quinidine. Jejunal segments of rats were mounted on diffusions chambers and the permeation of amitriptyline was measured across the tissue in luminal-serosal (LS) and serosal-luminal (SL) directions, with and without quinidine. Finally, an in situ recirculating intestinal perfusion model was performed in rabbits to study amitriptyline permeation in LS direction with and without quinidine. Absolute oral bioavailability (F) of amitriptyline was significantly increased more than three-fold in presence of quinidine (F = 0.6+/-0.4% versus 1.9+/-1.1%). The apparent permeability coefficients in SL direction were significantly higher than in LS direction (P(app (SL))=6.01+/-2.42 versus P(app (LS)) = 4.90+/-2.73 x 10(-4) cm min(-1)). In presence of quinidine, the intestinal absorption was increased (P(app (LS)) = 4.02+/-2.91 versus P(app (LS)) = 5.99+/-2.43 x 10(-4) cm min(-1)) and the intestinal secretion was decreased (P(app (SL)) = 4.58+/-0.54 versus P(app (LS)) = 3.63+/-1.46 x 10(-4) cm min(-1)) but not significantly. In conclusion, P-glycoprotein appears to be involved in oral amitriptyline absorption but other intestinal uptake and efflux transporters maybe implicated.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Blood-brain barrier penetration and pharmacokinetics of amitriptyline and its metabolites in p-glycoprotein (abcb1ab) knock-out mice and controls.

In earlier studies with P-gp (abcb1) knock-out mice, we showed that P-gp exports the antidepressants citalopram, paroxetine, venlafaxine and amitriptyline and its metabolites across the blood-brain barrier, thereby reducing cerebral bioavailability of some substances up to 9 times. The present study investigated the pharmacokinetics of amitriptyline and whether abcb1ab double knock-out mice metabolize amitriptyline and its metabolites differently. P-gp knock-out mice and controls received a s.c. injection of 10mug amitriptyline/g of body weight. The animals were sacrificed after 30, 60, 120 and 240min and concentrations of amitriptyline and its metabolites were measured with HPLC in brain, plasma, liver, kidney, spleen, lung, muscle, fat and ovaries. Cerebral concentrations of amitriptyline and its metabolites were higher in P-gp-deficient mice compared to controls. No significant group effect was found for spleen, liver, lung, kidney and fat tissue. The results of our study indicate that amitriptyline and its metabolites are substrates of P-gp. Overall pharmacokinetics between knock-outs and controls were very similar. This confirms the validity of the P-gp knock-out model and allows for a continued research of the interactions between P-gp, the blood-brain barrier and CNS substances such as antidepressants, neuroleptics and others.

ATP Binding Cassette Transporter, Subfamily B↗

Antinociceptive effects of the antidepressants amitriptyline, duloxetine, mirtazapine and citalopram in animal models of acute, persistent and neuropathic pain.

The effects of acute, systemic administration of amitriptyline, duloxetine and mirtazapine (antidepressant drugs that variously affect extracellular noradrenaline and serotonin levels) and the selective serotonin reuptake inhibitor (SSRI) citalopram were compared in rat models of experimental pain. None of the drugs (all 3-30 mg/kg, i.p.) affected acute nociceptive responses as measured in the tail flick test. In the hot plate test, duloxetine and mirtazapine significantly increased (P<0.05) the nociceptive response latency, whereas amitriptyline and citalopram were ineffective. In the formalin test, duloxetine and citalopram significantly attenuated, whereas amitriptyline and mirtazapine increased, second phase flinching behaviour (all P<0.05). However, amitriptyline and mirtazapine reduced second phase licking behaviour. In the chronic constriction injury model of neuropathic pain, thermal hyperalgesia of the injured hindpaw was significantly attenuated by all four drugs (P<0.05); only amitriptyline and duloxetine fully reversed thermal hypersensitivity. None of the drugs tested attenuated mechanical allodynia. In contrast amitriptyline, duloxetine and mirtazapine significantly reduced mechanical hyperalgesia (P<0.05); citalopram was ineffective. No drug-related effects on motor performance in the rotarod test were observed. These results (a) highlight the difficulty in correlating antinociceptive effects of drugs from different antidepressant classes across a range of animal pain models and (b) suggest that antidepressants that variously affect both noradrenaline and serotonin levels have more potent and efficacious antinociceptive effects than SSRIs (as exemplified by citalopram), against a range of pain-like behaviours in an animal model of neuropathic pain.

Acute Disease↗

Differential block of N-propyl derivatives of amitriptyline and doxepin for sciatic nerve block in rats.

BACKGROUND AND OBJECTIVES: The propyl group of ropivacaine ( N -propyl-2',6'-pipecoloxylidide hydrochloride) could be responsible for conferring some sensory selectivity to this drug. Thus, adding a propyl group to experimental local anesthetics (LAs) (e.g., the tricyclic antidepressants amitriptyline and doxepin) to increase sensory selectivity may be useful. We, therefore, synthesized N -propyl amitriptyline and N -propyl doxepin and investigated a potential predominance of sensory/nociceptive block over motor block (differential block) in a rat sciatic nerve block model. In addition, tetrodotoxin (TTX), a naturally occuring Na + channel blocker, was coinjected to investigate whether it increased block duration. METHODS: A 0.2-mL test dose of N -propyl amitriptyline and N -propyl doxepin, at a concentration of 1, 2.5, 5, and 10 mM, (alone or in combination with TTX at a concentration of 20 microM) was injected by the subfascial sciatic nerve approach. Motor function and sensory function (nociception) were evaluated by the force a rat's hind limb produced when pushing against a balance and the reaction to pinch, respectively. RESULTS: N -propyl amitriptyline and N -propyl doxepin demonstrated prolonged block duration, with N -propyl amitriptyline displaying significant differential block at higher concentrations (5 and 10 mM). The combination of either of these drugs with TTX increased the potency as well as the efficacy. Neurotoxicity commenced at concentrations of 5 to 10 mM. CONCLUSIONS: Detailed histopathologic nerve toxicity evaluations are justified to determine whether N -propyl amitriptyline has potential as a more sensory-selective local anesthetic at lower concentrations or as a predominantly sensory-selective neurolytic agent at higher concentrations.

Amitriptyline↗

Estimation of amitriptyline and its metabolites in serum and urine by GLC using nitrogen-specific detector.

1. A gas-chromatographic procedure for the estimation of amitriptyline and its metabolites in serum and urine using a nitrogen-specific detector is described. Specially cleaned glassware and purified solvents are used for the extraction of serum to further minimize extraneous peaks. Trimethylamine is added to serum before extraction to improve the recovery of drugs. Urine is refluxed at pH approximately 1 to hydrolyze the conjugates and to convert hydroxymetabolites to corresponding dehydro compounds. Serum is not hydrolyzed. 2. Two internal standards, one a tertiary amine similar in structure to amitriptyline and the other a secondary amine similar in structure to nortriptyline, are added to the specimen prior to extraction to obviate the need for accurate measurements of volumes during extraction and analysis. Urine and serum are washed with organic solvents at acidic pH to remove neutral and acidic impurities. Secondary bases are converted to their acetyl derivatives. 3. In the serum of a patient who is on amitriptyline therapy or who has ingested an overdose of amitriptyline, nortriptyline, a pharmacologically active metabolite is also measured. However, detection or estimation of hydroxymetabolites in serum is not clinically relevant. Hydroxylation index of an individual patient is determined by measuring the ratio of nortriptyline to its hydroxymetabolite in urine. 4. Amitriptyline and nortriptyline can be estimated in serum at a lower level of 10 and 20 ng/ml respectively. The procedure is linear over a wide range of amitriptyline and its metabolites. The use of an electronic integrator allows the estimation of different compounds with 100 fold difference in their concentration from the same chromatogram.

Amitriptyline↗

Adherence to treatment regimen in depressed patients treated with amitriptyline or fluoxetine.

OBJECTIVE: Non-compliance presents a constant challenge to effective therapy. Many studies only investigate early treatment discontinuation and not other measures like adherence to treatment regimen. We compared adherence in depressed patients using either a selective serotonin reuptake inhibitor (fluoxetine) or a tricyclic antidepressant (amitriptyline), and examined its clinical relevance through adverse events, drop-out rates, and outcome. Adherence was measured electronically with the MEMS (Medication Event Monitoring System). DESIGN: Nine-week double blind, randomized controlled trial. SETTING: Ambulatory psychiatric care. PATIENTS: Random sample of 66 depressed (DSM-III-R criteria) patients. INTERVENTION: Fluoxetine 20 mg or amitriptyline 150 mg. MAIN OUTCOME MEASURES: Time course of adherence and its relation to severe adverse events, drop-outs and outcome. RESULTS: Non-adherence to the treatment regimen occurred frequently in both treatment groups: 31% of patients had at least one 3-day drug holiday, and 34% of patients had at least one episode of three pills in a 24-h period. Over-consumption occurred more frequently during the early phases of treatment while under-consumption occurred more frequently during the later phases. Patients on amitriptyline (P=0.03) and patients with a higher pill intake (P=0.01) experienced more severe adverse events. Patients on amitriptyline (P=0.009) and patients with a lower adherence to the treatment regimen (P=0.004) discontinued from treatment more frequently. The final Hamilton score was significantly predicted by a longer duration of treatment and by a better adherence, but only in amitriptyline users. CONCLUSIONS: Non-adherence to the treatment regimen has important clinical consequences. Pharmacodynamics and human behavior predict risk for severe adverse events and drop-outs. Moreover, in amitriptyline users but not in fluoxetine users, better adherence predicts a better outcome.

Adult↗