Beta-blocking drugs and anxiety

The role of the locus coeruleus in the generation of pathological anxiety

This review aims to synthesise a large pre-clinical and clinical literature related to a hypothesised role of the locus coeruleus norepinephrine system in responses to acute and chronic threat, as well as the emergence of pathological anxiety. The locus coeruleus has widespread norepinephrine projections throughout the central nervous system, which act to globally modulate arousal states and adaptive behavior, crucially positioned to play a significant role in modulating both ascending visceral and descending cortical neurocognitive information. In response to threat or a stressor, the locus coeruleus–norepinephrine system globally modulates arousal, alerting and orienting functions and can have a powerful effect on the regulation of multiple memory systems. Chronic stress leads to amplification of locus coeruleus reactivity to subsequent stressors, which is coupled with the emergence of pathological anxiety-like behaviors in rodents. While direct in vivo evidence for locus coeruleus dysfunction in humans with pathological anxiety remains limited, recent advances in high-resolution 7-T magnetic resonance imaging and computational modeling approaches are starting to provide new insights into locus coeruleus characteristics.

Protective effect of propranolol and nadolol on social defeat-induced behavioral impairments in rats

Benzodiazepines and SSRIs are considered as standard treatment options for anxiety and depression, hallmarks of Post-Traumatic Stress Disorder (PTSD), although their use is often limited by adverse effects. While promising evidence emerged with β-adrenergic receptor (β-AR) antagonists (or 'β-blockers') and PTSD relief, efficacy issues dampened the excitement. However, we believe it is premature to completely eliminate a beneficial role of β-blockers. Our previous work has suggested that social defeat (SD) results in anxiety-like and depression-like behaviors in rats. Here, using the SD paradigm, we examined the effect of several β-adrenergic receptor antagonists (propranolol, nadolol, bisoprolol) on these behaviors in rats. Following acclimatization, Sprague-Dawley rats received no treatment (for control groups) or treated with ; propranolol (50 mg/kg/day in water), or nadolol (18 mg/kg/day in rats' chow), or bisoprolol (15 mg/kg/day in water). The treatment lasted for 36 days, following which rats were subjected to SD/control exposures (1 week). Later, anxiety-like and depression-like behaviors, social interaction and learning-memory function tests were conducted. SD rats exhibited anxiety- and depression-like behavior as well as learning-memory impairment. Propranolol and nadolol protected SD rats from exhibiting anxiety-or depression-like behaviors. Bisoprolol treatment did not mitigate SD-induced behavioral impairments in rats. Nadolol, propranolol or bisoprolol have no effect in attenuating SD-induced memory function tests. These results suggest that certain 'β-blockers' have the potential to mitigate the negative psychological effects of traumatic events.

Current knowledge of medications for the treatment of childhood anxiety disorders

OBJECTIVE

This report will review the costs, risks, and benefits of potentially useful medications for the treatment of children and adolescents with anxiety disorders and will identify areas where data are limited and additional research is needed.

METHOD

A Medline-assisted review of the literature was performed. Attention was given to dosage, response, and side effects of medications. Wherever possible, blinded, controlled medication trials in children with anxiety disorders (diagnosed by structured criteria) were targeted for use as the primary references. Relatively few systematic studies were found, so information from open trials and case reports also was included, as were controlled trials in adult populations.

RESULTS

The largest body of work supporting the use of medications for childhood anxiety came from studies of obsessive-compulsive disorder, where clomipramine and fluoxetine have been found effective in systematic studies. In other childhood anxiety disorders, there are conflicting data about the efficacy of medications, such as tricyclic antidepressants, benzodiazepines, serotonin reuptake inhibitors, beta-blockers, and monoamine oxidase inhibitors.

CONCLUSIONS

This review of the systematic pharmacological trials for childhood anxiety disorders revealed only 13 controlled studies: 5 for obsessive-compulsive disorder, 4 for school refusal/separation anxiety disorder, and 4 for avoidant/overanxious disorder or mixed diagnostic groups. Medications appear to be helpful for childhood anxiety disorders, although definitive pharmacotherapeutic data are lacking for many conditions. A systematic study of these medications is required to establish safety and efficacy in the pediatric age group. Evolving diagnostic criteria and terminology, the presence of comorbid diagnoses (especially affective disorders), and inadequate medication dosages may be factors hindering research in this field. Until additional research is done, clinicians must carefully consider the relative risk-to-benefit ratio when prescribing these medications.

Panic disorder. Pathophysiology and drug treatment

Advances over the past 2 decades in our understanding of the biology of panic disorder have paralleled a remarkable increase in the development of new pharmacological agents with antipanic effects. Although we can not presently use biological tests to help with our choice of therapeutic agent for individual patients, we can use this biological understanding in the development of overall pharmaco-therapeutic strategies. Current evidence does not support the hypothesis that panic disorder is associated with a primary disorder in one neurotransmitter system. Rather, the data suggest that the biological aetiology of panic disorder is related to abnormalities in the function of a variety of neurotransmitters including serotonin (5-hydroxytyrptamine; 5-HT), noradrenaline (norepinephrine), gamma-aminobutyric acid (GABA), dopamine, and cholecystokinin. It is likely, however, that panic disorder is a biologically heterogeneous condition and that biological subtypes may exist in which the primary abnormality may involve one or a few neurotransmitter systems. Currently, the data best support the hypothesis that pharmacotherapeutic agents with primary action at sites within the GABA and serotonin systems are the most effective in the treatment of panic disorder. Nevertheless, some patients will respond well to drugs with predominant activity in other systems, or may require pharmacotherapy designed to affect the function of more than 1 neurotransmitter. As our understanding of the biological aetiology of panic disorder evolves, the pharmacotherapeutic agents and strategies used in the treatment of this disorder will continue to evolve as well.

Behavioral and autonomic responses to intermittent social stress: differential protection by clonidine and metoprolol

The present study investigated physiological and pharmacological characteristics of socially "stressed" animals. Specifically, we examined (1) to what degree autonomic and behavioral "stress" reactions during intermittent confrontations between an intruder male adult Long-Evans rat with an aggressive resident undergo habituation, and (2) to what extent the defeat-experienced animal can be protected against these "stress" reactions with clonidine or metoprolol, two adrenergic agents with clinical anxiolytic effects. We developed an acute social stress situation that consisted of initially placing an experimental rat as an intruder into the homecage of a resident while the resident was not present, thereafter permitting brief physical agonistic interactions with the reintroduced resident until the intruder was forced into a submissive supine posture and emitted ultrasonic vocalizations (USV), and eventually exposing the intruder to the resident's threats for one hour, while being shielded from potentially injurious attacks ("threat encounter"). Over the course of the initial 4-weekly threat encounters the acute tachycardia but not the hyperthermic stress responses decreased in magnitude. Following the first three threat encounters core temperature (Tc) was significantly elevated for at least 3 h. The Tc was already elevated when the repeatedly defeated intruder was confronted with the olfactory cues of the resident's cage. This conditioned "anticipatory" hyperthermia developed in the course of the first three confrontations and was paralleled by a decrease in exploratory and motor behavior and by an increase in defensive behaviors and in both types of USV emitted in the "low" (20-30 kHz) and the "high" (31-70 kHz) frequency range. Clonidine (0.01-0.1 mg/kg, IP), an alpha 2-adrenergic agonist and metoprolol, a beta-adrenergic blocker (1.0-10.0 mg/kg, IP), dose-dependently prevented the tachycardic response to stress. Only clonidine, but not metoprolol, also attenuated the rise in Tc during the 1-h agonistic interaction. Clonidine decreased those aspects of motor behavior (e.g. rearing, walking) that are of lesser "cost" for the individual but maintained high levels of defensive reactions and increased the duration of "low" USV. The high doses of clonidine (0.06, 0.1 mg/kg) attenuated the homeostatic regulation and sedated the intruder while exposed to threats during a social confrontation. The absence of attenuation of the high level of defensive behavior and the prolonged "low" USV suggest a stress intensification by the higher doses of clonidine. In conclusion, after the fourth encounter, the autonomic, behavioral and vocal response pattern prior to and during repeated weekly confrontations show no evidence for habituation for the following 6 weeks.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of bisoprolol and diazepam in the treatment of cardiac neurosis

In order to compare the beta blockers bisoprolol and diazepam in the treatment of cardiac neurosis, 40 patients (16 males and 24 females, mean age: 39 +/- 11 years) were examined in a double-blind, crossover study. Following a 4-week placebo period, patients were randomized to receive either bisoprolol 10 mg daily or diazepam 5 mg twice daily for 4 weeks. After a second 4-week washout period on placebo, patients were switched to the alternative regimen for a further 4 weeks. At the end of the placebo periods and during each phase of treatment, the following parameters were evaluated: somatic symptoms by self-assessment questionnaire, anxiety state by Hamilton rating scale, reaction time to both acoustic and visual stimuli, blood pressure, and heart rate. Both treatments were effective in reducing somatic symptoms of cardiac neurosis, but bisoprolol was significantly more effective than diazepam (p less than 0.01). On the contrary, diazepam was superior to bisoprolol in improving the Hamilton scale related to psychic symptoms. Only diazepam prolonged reaction times. Both treatments were well tolerated; however, 12 patients complained of drowsiness and nine of sedation under diazepam. In conclusion, bisoprolol appeared to be as effective as diazepam in the treatment of cardiac neurosis, but with better effects on somatic symptoms and without affecting patients' psychomotor performance.

Effect of a beta-adrenergic blocking agent on dental anxiety

The effect of propranolol was studied on 23 dental phobics in a double-blind, placebo-controlled clinical trial involving actual dental treatment. The subjects were selected because they showed high physiological reactivity in the dental situation. Twelve subjects received the test drug and 11 subjects received the placebo at individualized doses of either 80 or 120 mg. A significant difference in self-reported anxiety at the injection phase of treatment and less overall pain intensity and aversiveness were observed for the propranolol as compared with the placebo group. No differences were detected for behavior ratings. Beta-adrenergic blocking agents may have utility for reducing anxiety in individuals fearful of dental treatment.

[Central effects of five beta-adrenergic receptor blockers in healthy volunteers: a quantitative EEG study]

The effects of five beta blockers on the central nervous system of healthy subjects was studied by computerized EEG analysis. All subjects underwent continuous recording with a Holter magnetic type recorder during the experimental period. For 10 consecutive days, five groups of subjects received alternately placebo and the beta blockers acebutolol 600 mg, carteolol 20 mg, metoprolol 200 mg, pindolol 30 mg and sotalol 320 mg. EEG recordings (C4/P4, P4/02 and C3/P3, P3/01) lasting 5 min were made between 8.30 and 9.30 a.m. Subjects were at rest with eyes closed and there was no vigilance control. The signal was recorded on a magnetic tape recorder and then processed by Nicolet MED 80 system. Comparisons of absolute and relative powers and of average frequencies were then made between the different sequences and groups. The possible correlations between the changes observed in the power spectrum and the clinical, pharmacological and pharmacokinetic specific properties of each beta blocker are discussed.

Isoproterenol-induced panic attacks

Eighty-six panic disorder patients and 45 nonpsychiatric controls were infused with isoproterenol at a rate of 1 microgram/min for up to 20 min in a placebo-controlled, double-blind study. Sixty-six percent of panic disorder patients experienced panic attacks during isoproterenol infusions, compared to 16% during placebo infusions. Nine percent of control subjects panicked with isoproterenol, but none panicked with placebo. Patients were more sensitive than controls to the anxiogenic effects of isoproterenol, as measured by subject self-ratings on a panic description scale. The frequency of panic attacks induced in patients was related to the dosage of isoproterenol; 79% of the patients who received a mean of 18.5 ng/min/kg of isoproterenol panicked. The panic attacks experienced by patients during isoproterenol infusions were similar to those experienced during placebo infusions.

Psychiatric and neuropsychological response to propranolol in Graves' disease

We describe the endocrine, psychiatric, and neuropsychological assessments of 10 untreated, newly diagnosed Graves' disease subjects who were studied longitudinally at three stages: hyperthyroid (stage 1), after 2 weeks of propranolol treatment (stage 2), and after 6 months of antithyroid treatment (stage 3). Major depression, generalized anxiety disorder, and hypomania were diagnosed at stage 1. Elevations on psychiatric symptom rating scales and in motor activity monitoring at stage 1 were significantly decreased at stage 2 and again at stage 3. Psychiatric improvements paralleled improvements in endocrine symptoms. Neuropsychological improvements were noted on the more challenging memory and attention tasks at stage 3, whereas propranolol treatment was not associated with changes on attention tests. Results are discussed in relation to catecholamine-thyroid hormone interactions, in particular, the beta-adrenergic system.

Beta-blockers in anxiety disorders

Studies evaluating the antianxiety and antipanic properties of beta-blockers do not support their routine use in treating either generalized anxiety disorder or panic disorder. The use of propranolol for anxiety disorders accompanied by physical symptoms, especially cardiovascular complaints, may be effective in some patients when combined with benzodiazepines or perhaps in some non-responders to conventional treatment. Better designed studies are needed to evaluate the exact role of beta-blocking agents in treating anxiety. The efficacy of propranolol in patients with panic disorder has not been widely researched, but preliminary results have not been encouraging. Propranolol may provide symptomatic relief in some patients with residual somatic complaints (i.e., palpitations and tachycardia), when combined with the patient's ongoing drug regimen. Because beta-blockers may induce depression, they should be used cautiously--if at all--in panic patients with concurrent depressive illness.

The antianxiety effect of beta-blockers on punished responding

Clinically effective anxiolytic drugs generally increase responding that is suppressed by punishment. Although beta-adrenergic antagonists have been reported to reduce anxiety in humans, such effects have not been reported reliably in animal punishment procedures. In the present study, three pigeons were trained to key peck under a multiple schedule. In the presence of a white light every thirtieth response produced grain. In the presence of a red light every thirtieth response produced grain and electric shock which suppressed responding to approximately 10 percent of that occurring in the alternate component. Propranolol (1.0-5.6 mg/kg) and, less reliably, atenolol significantly increased punished responding in a dose-related manner; propranolol effects were approximately twice as large as those of atenolol. Both drugs no more than weakly increased unpunished response rates at doses that increased punished responding. These results suggest that beta-blockers have an antianxiety effect on punished behavior, and that peripheral beta-blockade, the predominant action of beta-blockers regardless of whether they readily penetrate the brain, is likely to be involved in this effect.

Psychophysiological differentiation of two types of anxiety and its pharmacological modification by minor tranquillizer and beta-receptor-blocker

To evaluate the influence of beta-blockers and/or minor tranquillizers on autonomic reactions during brief stress, 48 healthy subjects were randomised into 4 groups: A = 4 mg Pindolol, B = 1.5 mg Cloxazolam, C = Placebo, D = 4 mg Pindolol + 1.5 mg Cloxazolam. Subjects underwent four stress situations: Counting, noise, mental arithmetic and ergometry, each lasting 4 min with rest periods of 8 min in between. Electromyogram, finger pulse amplitude, heart rate, pulse wave velocity and electrodermal activity were recorded simultaneously on-line. Analysis of variance showed that the two drugs had significant main effects in different systems: Pindolol reduced heart rate, mainly during mental arithmetic and ergometry, Cloxazolam reduced electrodermal activity, mainly during noise. It can be concluded that different structured situations with a varying amount and type of anxiety induce different autonomic reactions; these reactions can be differentially modified by the drugs applied.

A comparison of the effects of lorazepam with those of propranolol on experimentally-induced anxiety and performance

In a double-blind cross-over study the effects of propranolol (80 mg) and of lorazepam (1 or 2.5 mg) were assessed in normal student volunteers using a number of performance tests and mood-rating and bodily symptom questionnaires. Drug effects on experimentally-induced anxiety were also studied. The high dose of lorazepam impaired performance in digit-symbol substitution, symbol copying and verbal learning tests, and increased subjects' ratings of dizziness. Both lorazepam and propranolol increased simple reaction time. Lorazepam but not propranolol increased ratings of sedation. Although the stressor increased subjects' ratings of anxiety, neither drug altered anxiety ratings. Propranolol decreased and lorazepam increased subjects' pulse. These changes were not reflected in subjects' self-ratings - lorazepam caused a reduction in ratings of palpitations. The results suggest that if administered acutely, neither drug is beneficial in the treatment of short-term anxiety associated with intellectual stress.

CNS-related (side-)effects of beta-blockers with special reference to mechanisms of action

beta-Adrenoreceptor antagonists are liable to produce behavioural side-effects such as drowsiness, fatigue, lethargy, sleep disorders, nightmares, depressive moods, and hallucinations. These undesirable actions indicate that beta-blockers affect not only peripheral autonomic activity but also some central nervous mechanisms. In experimental animals beta-blockers have been found to reduce spontaneous motor activity, to counteract isolation-, lesion-, stimulation- and amphetamine-induced hyperactivity, and to produce slow-wave and paradoxical sleep disturbances. Furthermore, central effects such as tranquilizing influences are used for the treatment of conditions such as anxiety. Several different mechanisms of action could be responsible for these CNS effects: Centrally mediated specific actions on centrally located beta-adrenergic receptors, known to exist downstream from, and at the terminals of, 'vigilance-enhancing' central noradrenergic pathways. Centrally mediated specific actions on centrally located receptors of the non-adrenergic type; an affinity of some beta-blockers towards 5-HT-receptors is well documented. Centrally mediated non-specific actions on centrally located neurones, owing to the membrane-stabilizing effects of beta-blockers. Peripherally mediated actions whereby beta-blockers induce changes in the autonomic activity in the periphery, which are relayed to the CNS to induce changes in activity of a variety of central systems. It can be assumed that with any one of the beta-blockers all these mechanisms come into play, yet with varying degrees depending on characteristics of the drugs such as lipophilicity and hydrophilicity, the ratio of antagonist versus (partial) agonist properties, affinity to 'alien' receptor sites, strength of membrane-stabilizing activity, stereospecific affinity, and potency.

Brief report: effects of propranolol in Tourette syndrome

Alternate medications for the treatment of Tourette syndrome are required because haloperidol in some patients either may be ineffective or may cause disturbing side effects. Propranolol, a beta-adrenergic blocking agent, has been reported as effective, in uncontrolled trials, in ameliorating symptoms of tic disorder, tardive dyskinesia, and drug-induced extrapyramidal syndrome. Propranolol, in doses up to 120 mg per day, was administered to five patients with Tourette syndrome in a placebo-controlled study and was found ineffective in ameliorating symptoms of Tourette syndrome. Results underscored the importance of placebo-controlled investigation when evaluating the effects of drugs in Tourette syndrome.