Pindolol potentiates the antidepressant effect of venlafaxine by inhibiting 5-HT1A receptor in DRN neurons of mice.

INTRODUCTION: Antidepressants increase the level of 5-HT in the somatodendritic region of the serotonergic dorsal raphe nucleus (DRN) neurons in the first few days of their usage, which, in turn, inhibits the serotonergic neurons locally. Pindolol may eliminate this inhibition when used in combination with antidepressants. MATERIAL AND METHODS: We aimed to determine the effect of pindolol on 5-HT1A receptor response in the DRN neurons, using voltage clamp recordings and prove the potentiation of antidepressant effect of venlafaxine by pindolol through behavior experiments. Balb/c mice, 28-35 days-old were used. RESULTS: 5-HT application (25 µM) induced an outward current by 23.36 ± 3.79 pA at the neurons in the dorsal subnucleus of DRN. This effect was inhibited by pre-administration of WAY-100135 (21 µM) and pindolol (10 µM) separately. The current induced by 5-HT and 8-OHDPAT have no statistically significance. 8-OHDPAT (30 µM) induced a 5-HT-like outward current, which was inhibited by pre-administration of pindolol (10 µM). Combination of venlafaxine (20 mg/kg/day) and pindolol (15 mg/kg/day) significantly reduced immobilization time when compared to the control group in tail suspension test and forced swim test without any significant change in locomotor activity. Administration of venlafaxine (20 mg/kg/day) alone or pindolol (15 mg/kg/day) alone did not significantly reduce immobilization time. CONCLUSION: Pindolol has the potential to prevent the inhibition of serotonergic neurons after antidepressant use. Hence, we, for the first time, demonstrated that pindolol can potentiate antidepressant effect of venlafaxine. In the mood disorders, pindolol is likely to increase the effectiveness of antidepressant drugs when given in combination.

The anxiolytic effect of a promising quinoline containing selenium with the contribution of the serotonergic and GABAergic pathways: Modulation of parameters associated with anxiety in mice.

Recently, we demonstrated the promising anxiolytic action of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) in mice. For this reason, the objective of this study was to expand our previous findings by investigating the contribution of serotoninergic and GABAergic systems to the anxiolytic action of this compound. Pretreatment with different serotoninergic antagonists (pindolol, WAY100635 and ketanserin) blocked the anxiolytic effect caused by 4-PSQ (50 mg/kg, per oral) in the elevated plus maze (EPM) test. The contribution of the GABAergic system was investigated by pretreatment with pentylenetetrazole (a GABAA receptor antagonist) (PTZ). 4-PSQ diminished the PTZ-induced anxiety, and did not modify the locomotor, exploratory and motor activities of mice. Later, this group of animals was euthanized and the blood was removed to determine the levels of corticosterone, and cerebral cortex and hippocampus to determine the mRNA expression levels of cAMP response element binding protein (CREB), brain derived neurotrophic factor (BDNF) and nuclear factor kappa B (NF-κB), as well as the Na+, K+ ATPase activity and reactive species (RS) levels. 4-PSQ was able to significantly reverse the increase in RS and corticosterone levels, as well as the decrease of CREB and BDNF expression in the cerebral structures and increase of NF-κB expression in the hippocampus. Finally, 4-PSQ restored the Na+, K+ ATPase activity in the cerebral structures evaluated. Here, we showed that the modulation of serotonergic and GABAergic systems, factors related to neurogenesis, oxidative status and Na+, K+ ATPase activity contributes to the anxiolytic effect of 4-PSQ and reinforces the therapeutical potential of this compound for the treatment of anxiety.

Is pindolol augmentation effective in depressed patients resistant to selective serotonin reuptake inhibitors? A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis was conducted to assess the use of pindolol augmentation in depressed patients resistant to selective serotonin reuptake inhibitor (SSRI) therapy. METHODS: A comprehensive search of PubMed, Cochrane, Embase, Web of Science, and PsychINFO databases from 1970 through December 2013 was conducted. Only randomized controlled trials (RCTs) studied on unipolar SSRI-resistant depressed adults were included. The primary outcome was mean change scores of depressive symptom on the depression rating scales, assessed with standardized mean differences. RESULTS: Five RCTs consisting of 154 patients met all inclusion and exclusion criteria. The overall pooled effect size in the primary and secondary efficacy analysis showed no significant effects of pindolol plus SSRI therapy (standardized mean difference = -0.43, p = 0.24; OR = 1.92, p = 0.39, respectively). In terms of acceptability, there was no statistical difference in either tolerability or safety between the two groups (OR = 0.46, p = 0.40; OR = 0.90, p = 0.94, respectively). These estimates remained robust through several sensitivity and subgroup analyses, except 7.5 mg-qd pindolol augmentation did show a significant benefit over 2.5-mg tid pindolol augmentation. CONCLUSIONS: Pindolol augmentation may not be suitable for treatment-resistant depression patients with SSRI-resistant depression. However, once-daily high-dose pindolol (7.5 mg qd) appears to show a promising benefit in these patients.

A Randomized Controlled Trial comparing the efficacy of low-dose amitriptyline, amitriptyline with pindolol and surrogate placebo in the treatment of chronic tension-type facial pain.

BACKGROUND: Patients often present to otolaryngologists with chronic facial pain, presumed to be of sinus origin despite normal nasal endoscopy and sinus CT. This pain has increasingly been recognized as being of neurological origin with one of the commonest underlying causes being mid-facial segmental tension-type pain (MFP) which is a version of tension-type headache affecting the midface. PRIMARY OUTCOME MEASURES: 1. To determine whether low-dose amitriptyline reduces pain scores compared to surrogate placebo in patients with chronic MFP. 2. To determine whether the addition of pindolol, a beta blocker with serotonin receptor blocking properties hastens onset of action or improves efficacy of amitriptyline. SECONDARY OUTCOME MEASURE: to determine whether amitriptyline or amitriptyline with pindolol significantly reduces analgesic consumption. METHODOLOGY: Sixty two patients were randomized to three treatment groups (a) amitriptyline 10mg daily (b) amitriptyline 10mg daily with pindolol 5mg twice daily and (c) loratadine 10mg daily. Daily pain scores using a facial pain diary were recorded over eight weeks. RESULTS: At 8 weeks, pain frequency and intensity were significantly reduced in patients treated with amitriptyline and in those receiving amitriptyline with pindolol compared to surrogate placebo. Patients on the combination therapy showed significantly improved clinical outcome and significantly reduced analgesic intake compared to those on amitriptyline alone. CONCLUSION: Low dose amitriptyline is effective in the management of MFP and is enhanced by the addition of pindolol.

Both acute and subchronic treatments with pindolol, a 5-HT(1A) and ß1 and ß2 adrenoceptor antagonist, elevate regional serotonin synthesis in the rat brain: an autoradiographic study.

Antidepressant treatments, including those that increase serotonin (5-HT) neurotransmission, require several weeks or months until the onset of the therapeutic effect in depressed patients. The negative feedback on 5-HT transmission exhibited by the 5-HT(1A) and 5-HT(1B) autoreceptors has been postulated as a possible delaying factor. The aim of the present study was to assess the effect of the acute and subchronic treatment with pindolol, a 5-HT(1A/1B,) ß1 and ß2 adrenoceptor antagonist, on 5-HT synthesis, one of the key parameters of 5-HT neurotransmission. Male Sprague-Dawley (SPD) rats (180-220 g) were treated with pindolol or an adequate volume of saline, administered either acutely (15 mg/kg i.p.; SPD-AC-SAL, SPD-AC-TR) or subchronically (15 mg/kg day i.p. for 7 days; SPD-SUBCHR-SAL, SPD-SUBCHR-TR). Thirty minutes following the single i.p. injection (acute experiment) or at the 8th day following the commencement of the subchronic treatment (subchronic experiment), 5-HT synthesis was measured using α-[¹4C]methyl-L-tryptophan autoradiography. The analysis of variance (ANOVA), followed by the Benjamini-Hochberg correction for multiple comparisons, revealed: (1) a significant increase of 5-HT synthesis in the SPD-AC-TR rats, relative to the SPD-AC-SAL rats in all brain regions examined except the substantia nigra--pars reticularis, dorsal subiculum, inferior olive, raphe magnus and raphe obscurus and (2) a significant increase of 5-HT synthesis in the SPD-SUBCHR-TR rats, relative to the SPD-SUBCHR-SAL rats in all brain regions except the median raphe, hypothalamus and raphe pontine. On the basis of these results, we hypothesized that the antagonism of the 5-HT(1A/1B) receptors prevents the negative feedback mediated by these receptors on 5-HT synthesis, resulting in a persistent increase of 5-HT synthesis. The results accord with clinical reports on the utility of pindolol in the augmentation of antidepressant treatment.

Can we really accelerate and enhance the selective serotonin reuptake inhibitor antidepressant effect? A randomized clinical trial and a meta-analysis of pindolol in nonresistant depression.

OBJECTIVE: Since depression entails not only dramatic personal disruption but also a huge amount of medical and socioeconomic burden, slowness of antidepressant action and difficulties to attain remission are entangled issues to be solved. Given the controversial previous findings with enhancing strategies such as pindolol, we examined whether the speed of selective serotonin reuptake inhibitor (SSRI) action can be truly accelerated with optimized pindolol dosage. Additionally, we aimed at elucidating whether pindolol benefits emerge, particularly in a population with nonresistant depression. METHOD: Thirty outpatients with major depressive disorder (DSM-IV criteria) recruited between December 2002 and November 2005 were randomly assigned to receive citalopram + pindolol (5 mg tid) or citalopram + placebo for 6 weeks in a double-blind randomized clinical trial. A meta-analysis of randomized controlled trials of pindolol augmentation in patients with nonresistant depression was also performed. Outcome criteria were based on the 17-item Hamilton Depression Rating Scale. For the meta-analysis, efficacy was assessed by the number of treatment responders at 2 weeks and 4-6 weeks. RESULTS: Clinical trial outcomes: Repeated-measures analysis of variance showed a significant group-by-time interaction (P = .01). Cumulative percentage showed a trend for sustained response (odds ratio [OR] = 2.09; 95% CI, 0.914-4.780; P = .08) and a well-defined increased likelihood of sustaining remission (OR = 5.00; 95% CI, 1.191-20.989; P = .03) in pindolol receivers. Median survival time until first response was 65% less in the pindolol group (22 days vs 30 days; P = .03). The negative binomial regression model yielded different rates of response per person-day for pindolol and placebo groups (7.6% vs 4.7%, respectively; P = .03). Meta-analysis: Outcome favored pindolol at 2 weeks' time (relative risk [RR] = 1.68; 95% CI, 1.18-2.39; P = .004) and also at 4-6 weeks' time (RR = 1.11; 95% CI, 1.02-1.20; P = .02). CONCLUSIONS: Present findings represent further evidence of the acceleration and enhancement of efficacy with pindolol administered together with SSRIs, displaying a quicker and more pronounced decrease of symptoms in patients with nonresistant major depressive disorder. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00931775.

Pindolol potentiates the panicolytic effect of paroxetine in the elevated T-maze.

AIMS: the ß-adrenergic and 5-HT(1A) receptor antagonist pindolol has been used in combination with antidepressant drugs, to shorten the time of onset of clinical efficacy and/or increase the proportion of responders in depressive and anxiety disorders. The aim of this study was to examine the interaction between pindolol and the selective serotonin reuptake inhibitor (SSRI), paroxetine in rats submitted to the elevated T-maze (ETM). MAIN METHODS: for assessing the drug combination effect, rats were administered with pindolol before paroxetine, using oral or intraperitoneal (i.p.) routes of acute administration, and were submitted to the ETM model. KEY FINDINGS: the highest dose of pindolol used (15.0mg/kg, i.p.) increased both inhibitory avoidance and escape latencies in the ETM, probably due to nonspecific motor deficit, since locomotion in a circular arena was also significantly decreased. The highest dose of paroxetine (3.0mg/kg, i.p.) selectively impaired escape, considered a panicolytic effect. Combination of pindolol (5.0mg/kg, i.p.) with an ineffective dose of paroxetine (1.5mg/kg, i.p.) impaired escape, indicating a potentiation of the panicolytic effect of paroxetine. By the oral route, neither paroxetine (3.0mg/kg) nor pindolol (5.0mg/kg) alone were effective, but the combination treatment had a marked panicolytic effect, again indicating drug potentiation. SIGNIFICANCE: the present results show that the combination of the ineffective doses of pindolol and paroxetine significantly increased escape latency, indicating a selective panicolytic effect. These findings give preclinical support for the use of this drug combination in the treatment of panic disorder (PD).

Glomerular filtration rate after tramadol, parecoxib and pindolol following anaesthesia and analgesia in comparison with morphine in dogs.

OBJECTIVE: To compare the effects of morphine, parecoxib, tramadol and a combination of parecoxib, tramadol and pindolol on nociceptive thresholds in awake animals and their effect on glomerular filtration rate (GFR) in dogs subjected to 30 minutes of anesthesia. ANIMALS: Eight adult mixed breed experimental dogs. STUDY DESIGN: Randomized, controlled trial. METHODS: Dogs received 0.05 mg kg(-1) acepromazine subcutaneously (SC) as anaesthetic pre-medication. Thirty to sixty minutes later, they received either tramadol 3 mg kg(-1) intravenously, (IV), parecoxib (1 mg kg(-1) IV), a combination of tramadol 3 mg kg(-1) (IV), parecoxib 1 mg kg(-1) (IV) and pindolol 5 microg kg(-1) (SC), morphine (0.1 mg kg(-1) (IV) or 0.9% saline (2 mL). Anaesthesia was then induced with IV propofol to effect (2.9 +/- 0.8 mg kg(-1)) and maintained with halothane in oxygen for 30 minutes. Systolic arterial blood pressure was maintained above 90 mmHg with IV fluids and by adjusting the inspired halothane concentration. Post-treatment nociceptive thresholds to mechanical stimuli, expressed as percent of pre-treatment values, were compared between the treatments to assess the analgesic efficacy of the drugs. Plasma iohexol clearance (ICL), a measure of GFR, was estimated both before and 24 hours after induction of anaesthesia to study the drugs' effects on renal perfusion. Nociceptive threshold and GFR data were compared using mixed model analysis in SAS 9.1. RESULTS: Both tramadol and parecoxib produced similar analgesia, which was less than that of morphine. Their combination with pindolol produced analgesia comparable with morphine. None of the test drugs, either alone or in combination, reduced GFR. CONCLUSION: Tramadol and parecoxib (either alone or in combination) can increase nociceptive thresholds in awake dogs and have minimal effects on renal perfusion in normotensive dogs subjected to anaesthesia.

Once-daily high-dose pindolol for paroxetine-refractory premature ejaculation: a double-blind, placebo-controlled and randomized study.

PURPOSE: To evaluate the efficacy and safety of pindolol 7.5 mg/d in delaying of ejaculation in paroxetine-refractory patients. MATERIALS AND METHODS: Eighty-six married men (mean age, 33 years) with premature ejaculation unresponsive to paroxetine 20 mg/d given for 2 months or longer were randomized to receive 7.5 mg pindolol (n = 44) (group 1) (PXT + POL) or placebo (n = 42) (group 2) (PXT + PBO) for 6 weeks, while continuing paroxetine. After 6 weeks, all patients received paroxetine and placebo and were followed for 3 further weeks in a single-blind manner. Pretreatment evaluation included history and physical examination, mean intravaginal ejaculatory latency time (IELT), International Index of Erectile Function (IIEF), and Meares-Stamey test. The efficacy of 2 treatments was assessed every 1 week during treatment and, at the end of study, using responses to IIEF, IELT evaluation, mean intercourse satisfaction domain, mean weekly coitus episodes, and adverse drug effects. RESULTS: Seventy-seven (89.5%) completed the whole treatment schedule. At the end of 6-week treatment period, the IELT after paroxetine-pindolol and paroxetine-placebo gradually increased from mean 48 and 41 seconds to approximately 188 and 58 seconds, respectively (P = 0.001). The mean weekly intercourse episodes increased from pretreatment values of 1.5 and 1.5 to 2.7 and 1.7, for groups PXT + POL and PXT + PBO, respectively (P = 0.01). Baseline mean intercourse satisfaction domain values of IIEF 12 and 11 reached to 16 and 11 at 6-week treatment in PXT + POL and PXT + PBO groups, respectively (P = 0.01). Upon discontinuing pindolol, all outcome measures returned to baseline values rapidly. The incidence of side effects with paroxetine-pindolol was significantly higher (P = 0.04). CONCLUSIONS: These findings support that a single high dose of pindolol (7.5 mg) is an effective augmentation strategy in paroxetine-refractory patients.

Selective verbal and spatial memory impairment after 5-HT1A and 5-HT2A receptor blockade in healthy volunteers pre-treated with an SSRI.

Serotonergic neurotransmission has been implicated in memory impairment. It is unclear however if memory performance is mediated through general 5-HT availability, through specific 5-HT receptors or both. The aim of the present study was to assess the contribution of 5-HT reuptake inhibition and specific blockade of 5-HT(1A) and 5-HT(2A) receptors to memory impairment. The study was conducted according to a randomized, double-blind, placebo-controlled, four-way cross-over design including 16 healthy volunteers. The treatment consisted of oral administration of escitalopram 20 mg + placebo, escitalopram 20 mg + ketanserin 50 mg, escitalopram 20 mg + pindolol 10 mg and placebo on 4 separate days with a washout period of minimum 7 days. Different memory tasks were performed including verbal memory, spatial working memory and reversal learning. Escitalopram showed an impairing effect on immediate verbal recall which nearly reached statistical significance. No effects of escitalopram were found on other types of memory. In combination with pindolol, immediate verbal recall was significantly impaired. Escitalopram in combination with ketanserin impaired spatial working memory significantly. No effects were found on reversal learning. Selective impairment of immediate verbal recall after a 5-HT(1A) partial agonist and selective impairment of spatial working memory performance after 5-HT(2A) receptor antagonist, both in combination with a selective serotonergic reuptake inhibitor (escitalopram), suggests that 5-HT(1A) and 5-HT(2A) receptors are distinctly involved in verbal and spatial memory.

The role of 5-HT1a and 5-HT2a receptors in attention and motor control: a mechanistic study in healthy volunteers.

RATIONALE: Various studies have demonstrated a modulating role for serotonin in attention. Selective serotonin inhibitors have repeatedly been shown to impair performance in sustained attention tasks. OBJECTIVES: To assess the contribution of serotonin reuptake inhibition and specific blockade of the pre-synaptic 5-HT(1a) receptor and the 5-HT(2a) receptor to deficits in attention. MATERIALS AND METHODS: The study was conducted according to a randomized, double-blind, placebo controlled, four-way crossover design including 16 healthy volunteers. Treatments consisted of oral administration of the selective serotonin reuptake inhibitor (SSRI) escitalopram 20 mg + placebo; escitalopram 20 mg + ketanserin (5-HT(2a) antagonist), 50 mg; escitalopram 20 mg + pindolol (5-HT(1a) antagonist) 10 mg; and placebo + placebo on four separate days. A range of performance tasks were conducted to assess the subjects' attention and motor functions. RESULTS: Escitalopram administered alone impaired tracking performance in a divided attention task. The combination of escitalopram and pindolol and escitalopram and ketanserin impaired divided attention as compared to placebo. In addition, escitalopram and ketanserin impaired sustained attention. Divided attention impairment observed after combined treatments did not significantly differ from impairments after escitalopram alone. Sustained attention impairment observed after combined escitalopram and ketanserin significantly differed from escitalopram alone. CONCLUSIONS: 5HT(1a) blockade hardly affected SSRI effects on attention. Additional 5HT(2a) blockade, however, produced impairments of sustained attention and motor impulse control.

Pindolol augmentation of antidepressant response.

Pindolol, a partial beta-adrenoceptor/5-HT1A receptor antagonist was first used to accelerate the onset of action of antidepressant drugs in 1994. Since then, it has been used in more than a dozen controlled trials to examine whether it can reduce the lag to clinical improvement, and/or improve the clinical response in treatment-resistant patients. A recent metaanalysis concluded that pindolol accelerates the antidepressant response but does not increase the effectiveness of SSRIs in unresponsive patients. Several studies have examined the pharmacology of pindolol to clarify the neurobiological basis of its clinical action. Pindolol was initially used due to its ability to block 5-HT1A receptor-mediated responses and to enhance the neurochemical effects of SSRIs. In transfected cells, however, pindolol is a weak (20-25%) partial agonist at 5-HT1A receptors and, as such, its actions greatly depend on the system used. In line with this, other reports have also shown that pindolol can reduce serotonergic cell firing when given alone. Positron emission tomography (PET) scan studies have shown that pindolol displays a preferential occupancy of pre- vs. postsynaptic 5-HT1A receptors, although the overall occupancy is lower than desirable, which suggests that higher doses (e.g., 15 mg/day) may be more effective than the currently used 7.5 mg daily dosage. However, given the complex pharmacology of pindolol, it is hoped that new developments in this field can proceed through the use of a) selective and silent 5-HT1A receptor antagonists in combination with SSRIs, or b) dual action agents (SSRI+5-HT1A receptor blockers).

Positron emission tomography studies of human airways using an inhaled beta-adrenoceptor antagonist, S-11C-CGP 12388.

OBJECTIVES: Positron emission tomography (PET) scanning may provide information on changes in the density and affinity of airway beta-adrenoceptors in lung diseases. However, the injection of a radiolabeled beta-blocker results in a pulmonary PET signal that reflects the binding of the ligand in the alveoli and not in the airways. Better discrimination between alveolar and airway beta-adrenoceptors may be possible with an inhaled radioligand. DESIGN: A nebulizer was used to administer the antagonist S-11C-CGP12388 in aerosol form. Eight volunteers inhaled the tracer twice, at baseline and after pretreatment with a beta-adrenergic drug. In both PET scan studies, a dynamic scan of the lungs was followed by a whole-body scan to assess the inhaled dose. Pulmonary uptake was quantified using a region-of-interest-based analysis. SETTING: University hospital. PARTICIPANTS: Healthy volunteers. INTERVENTIONS: Pretreatment consisted either of inhaled salbutamol (400 microg, 20 min before the scan), or orally administered pindolol (3 x 5 mg during a period of 16 h before PET scanning). RESULTS: Drug pretreatment did not affect pulmonary deposition of the radioligand. The agonist salbutamol accelerated the monoexponential washout of 11C not only in the peripheral lung (mainly alveoli), but also in the central lung (mainly airways) and in the main bronchi. An even larger increase of the washout rate was induced by the antagonist pindolol. CONCLUSION: The similar effects of pindolol and salbutamol on tracer kinetics suggest that accelerated washout is due to the blockade of beta-adrenoceptors. Thus, the interaction of drugs with airway beta-adrenoceptors can be visualized using PET scanning and an inhaled radioligand.

Pindolol augmentation of selective serotonin reuptake inhibitors: accounting for the variability of results of placebo-controlled double-blind studies in patients with major depression.

Co-administration of pindolol with SSRIs in patients with depression has been suggested as a way to both hasten and augment antidepressant response. Clinical trials have examined the efficacy of this treatment regime and conflicting results have been reported. The present review briefly presents the results of placebo-controlled double-blind trials of pindolol augmentation of SSRIs in patients with major depression, and focuses on factors that may account for the variability of findings. Additionally, a profile of the subset of patients who may most benefit from pindolol augmentation is outlined. Methodological factors such as qualitative differences in definitions of antidepressant response, the timing of pindolol administration and heterogeneous clinical characteristics of patient samples may contribute to the variability in the results of clinical trials to date. Similarly, individual differences in neuropathology, neurophysiology and genotype may also account for some of the inconsistencies in the findings. Finally, the results of recent neuroimaging studies suggest that the 2.5 mg t.i.d. dose of pindolol that has been used in all but one of these investigations may be suboptimal for achieving reliable and significant occupancy of 5-HT1A autoreceptors and may explain the contradictory nature of the results of investigations of pindolol augmentation.

Noradrenergic activity is associated with response to pindolol in aggressive Alzheimer's disease patients.

Loss of noradrenergic (NE) neurones in the locus ceruleus and compensatory changes in NE activity have been described in Alzheimer's disease (AD), but have never been linked to treatment. The hypothesis of this study was that central NE responsivity would predict aggression response to treatment with a NE medication, pindolol. Fifteen institutionalized AD subjects [Mini-Mental State Examination (MMSE), mean 3.3 +/- 4.6] with significant behavioural disturbances (Neuropsychiatric Inventory Score, mean 30.6 +/- 14.6) were studied. Growth hormone (GH) response to clonidine challenge (5 microg/kg) was used as a measure of central NE responsivity. Subjects were then randomized to 7 weeks of treatment with pindolol, maximum dose 20 mg b.i.d., or an identical placebo capsule in a cross-over design. The primary outcome measure was change on the retrospective Overt Aggression Scale (r-OAS). Five of 11 completers (45%) had decreased total r-OAS scores. There was significant improvement noted on the r-OAS verbal aggression subscale (paired t = -2.5, p = 0.03) compared to placebo, but not r-OAS total. Higher baseline aggression, higher MMSE and lower GH response predicted improvement in aggression, accounting for 82% of the variance (r = 0.91, F = 10.5, p = 0.006). Changes in NE responsivity, as reflected by a blunted GH response to clonidine challenge and more severe aggression, were associated with better response to the NE agent pindolol. Individual patient characteristics, including underlying neurotransmitter changes, may be useful for predicting response to therapy.

Once-daily high-dose pindolol for SSRI-refractory depression.

Selective serotonin reuptake inhibitor (SSRI) augmentation with the 5-HT1A antagonist pindolol has met with mixed results. Recent studies using positron emission tomography (PET) suggest that pindolol doses used in these studies were too low to effect 5-HT1A autoreceptor blockade. To test the hypothesis that a single higher dose of pindolol would effectively augment antidepressant responses in SSRI-refractory patients, nine subjects with major depression unresponsive to paroxetine 40 mg/day given for 2 months or more were randomized to AM pindolol 7.5 mg (n=4) or placebo (n=5). Subjects were administered the Hamilton Depression Scale (HAM-D), the Hamilton Anxiety Scale (HAM-A), the Bech-Rafaelsen Melancholia Scale, and the Zung Depression Inventory at baseline and weeks 1, 2, 3, and 4. Subjects receiving pindolol exhibited significant improvements in all ratings beginning at week 2 which continued through week 4. Aside from transient dizziness and a five-point decrease in systolic/diastolic blood pressure associated with pindolol, no adverse effects were reported. Although results must be verified in a larger sample, these findings support previous studies indicating that pindolol can accelerate antidepressant responses during SSRI therapy. In addition, results reported here suggest that a single high dose of pindolol (7.5 mg) is a more effective augmentation strategy in SSRI-refractory patients compared with the same total dose given at 2.5 mg tid.

Pindolol augmentation in depressed patients resistant to selective serotonin reuptake inhibitors: a double-blind, randomized, controlled trial.

BACKGROUND: Studies of pindolol augmentation of antidepressants in major depressive disorder have produced mixed results, and data in treatment-resistant patients are limited. Here, we report on a double-blind, randomized, controlled 6-week study of pindolol augmentation of selective serotonin reuptake inhibitors (SSRIs) in depressed outpatients resistant to SSRI monotherapy. METHOD: Forty-two outpatients with DSM-IV major depressive disorder who had an insufficient response to an adequate trial of an SSRI (fluoxetine, paroxetine, or sertraline) were randomly assigned to pindolol, 2.5 mg t.i.d., or sham augmentation, in addition to continued SSRI administration. For separate analysis, the control group underwent a single-blinded switch to pindolol, 2.5 mg t.i.d., from week 4 through week 6, while the active group was continued on pindolol augmentation (hemi-crossover design). Change in Hamilton Rating Scale for Depression (HAM-D) score from baseline to the end of week 3 was the primary outcome measure. Data were gathered from February 1994 to August 1998. RESULTS: Thirty-eight patients completed at least 1 week on protocol, with 21 and 17 randomly assigned to the pindolol and control groups, respectively. After 3 weeks on protocol, partial response rates (i.e., minimum 50% decrease from baseline in HAM-D score and maximum absolute score of 15) for the pindolol (19% [4/21]) and control (24% [4/17]) groups were comparable. At 3 weeks, the pindolol and control groups demonstrated mean +/- SD decreases in HAM-D scores of 6.5 +/- 9.8 and 9.7 +/- 7.2, respectively. There were no significant differences in antidepressant response or side effects between the 2 groups. CONCLUSION: These results do not support the efficacy of pindolol in augmenting clinical response to SSRIs in treatment-resistant depressed patients.