Antidepressant-related erectile dysfunction: management via avoidance, switching antidepressants, antidotes, and adaptation

The ideal antidepressant would control depression with no adverse effect on sexual function. Erectile dysfunction and other sexual dysfunction associated with antidepressant medication treatment are problems with many antidepressants and can lead to patient dissatisfaction and decreased compliance with treatment. A computerized MEDLINE search (English language, 1966-2003) was performed using the terms antidepressive agents, erectile dysfunction, and sexual dysfunction. Emphasis was placed on studies with specific sexual function measurements taken before and after treatment and placebo control. Mixed mediator, nonserotonergic antidepressants that block postsynaptic serotonin type 2 receptors (nefazodone, mirtazapine) or that primarily increase dopamine or norepinephrine levels (bupropion) were thought to be good choices for avoiding antidepressant-associated sexual dysfunction or for switching patients in whom antidepressant-associated sexual dysfunction emerged. Comparisons with serotonin reuptake inhibitors (SRIs) have revealed less desire and orgasm dysfunction with nonserotonergic bupropion, less orgasm dysfunction with nefazodone, and superior overall satisfaction with sexual functioning with bupropion or nefazodone. However, most of these studies have design flaws that make evidence-based claims of efficacy difficult to substantiate. Agents proposed for antidote use in antidepressant-associated sexual dysfunction have either not been studied in men or not proved efficacious in randomized placebo-controlled trials. Switching to and augmentation with bupropion or nefazodone have also not clearly shown efficacy in controlled trials and require care and monitoring to avoid SRI discontinuation symptoms and loss of antidepressant efficacy. Few proposed treatment options, apart from avoidance, have proved effective for antidepressant-associated sexual dysfunction, which can have negative consequences on depression management.

Sexual dysfunction induced by serotonin reuptake antidepressants

Serotonin reuptake inhibitor (SRI) antidepressants have been associated with sexual dysfunction, though there have been few prospective reports specifically examining this problem. The purpose of this study was to determine if three SRIs affected sexual function in patients with an anxiety disorder or major depressive disorder over a 3-month period. Sixty-one patients were evaluated for at least 2 months in a prospective study of the effects of fluoxetine, sertraline, and paroxetine on five aspects of sexual function: libido, erection/lubrication, orgasm quality, orgasm delay, and sexual frequency. Measurements were made at baseline and at each month on visual analog scales. For men and women, orgasm quality was lower and orgasm delay longer at Months 1, 2, and 3 compared with baseline (p < .001). Erection scores were lower over time (p < .02) but this change was less dramatic. Lubrication, libido, and sexual frequency were not appreciably changed over 3 months. Anorgasmia was significantly more common in women than men at Months 1 and 2. Orgasm appears to be a primary sexual function affected by SRIs.

Tardive dyskinesia in older out-patients: a follow-up study

Tardive dyskinesia (TD) is a long-term potential adverse effect of neuroleptic treatment, and older age has been correlated with the development of TD. We conducted a chart review of current out-patients and examined annual Abnormal Inventory Movement Scale (AIMS) evaluations for the period 1987-1995 for 43 patients who started neuroleptic treatment after the age of 35 years. Patients (mean age 67 years) began neuroleptic treatment at a mean age of 46 years and were taking neuroleptics for 18 years on average. A total of 18 patients (42%) met the research criteria for TD, of whom all cases were mild except for three, which were moderate. Although TD was common, it rarely progressed in this naturalistic setting, suggesting that even for older patients maintenance neuroleptic treatment may be feasible for chronic psychosis.

Dynorphin A-induced rat spinal cord injury: evidence for excitatory amino acid involvement in a pharmacological model of ischemic spinal cord injury

Dynorphin A reduced lumbosacral blood flow, elevated cerebrospinal fluid lactic acid concentrations and caused flaccid hindlimb paralysis and striking neuropathological changes after its injection into the spinal subarachnoid space in rats. Coadministration of the vasodilator hydralazine substantially eliminated the paralytic, anaerobic metabolic and neuropathological responses to dynorphin A. In contrast, in concentrations up to 1 mM, dynorphin A did not alter the viability of cultured rat spinal cord neurons. Thus, it appears that this peptide lacks direct neurotoxic effects and that neuronal injuries in vivo result primarily from ischemia associated with dynorphin A-induced blood flow reductions. NMDA receptor antagonists significantly improved recovery from dynorphin A-induced hindlimb paralysis, and substantially eliminated neuropathological changes without attenuating the acute blood flow reductions or lactic acid elevations. Additionally, glutamate and aspartate concentrations were increased significantly in spinal cord cerebrospinal fluid samples removed during the time that peptide-induced spinal cord blood flow reductions were observed. In contrast, neither amino acid concentration was elevated in media removed after 1-hr exposure of spinal cord neuronal cell cultures to 100 microM concentrations of dynorphin A. These results indicate that the paralysis and spinal cord injuries produced in rats after spinal subarachnoid injection of dynorphin A result predominantly from spinal cord ischemia, and further identify excitatory amino acids and N-methyl-D-aspartate receptor mechanisms as important mediators in this injury model.

Procainamide-induced myasthenia-like weakness and dysphagia

A 64-year-old man with chronic renal insufficiency was hospitalized with dysphagia and inability to keep his head erect 11 months after beginning procainamide hydrochloride (PA) for control of atrial flutter. Evaluation revealed esophageal dysmotility, worsening renal function, and elevated serum PA and N-acetylprocainamide (NAPA) concentrations. No evidence of autoimmune myasthenia gravis was found. PA was discontinued and normalization of PA and NAPA concentrations was associated with a decrease in muscle weakness and resolution of dysphagia. The correlation between clinical findings and serum concentrations of PA and NAPA suggests that drug excess due to impaired clearance was the basis for this unusual adverse drug reaction.

Physiologic benefits of a stress reduction program for healthy middle-aged Army officers

Stress reduction programs (SRPs) can reduce morbidity and mortality in patients with coronary artery disease (CAD). This study evaluated the effect of an SRP on metabolic and hormonal risk factors for CAD. Twenty army officers participating in an SRP, Group I, and a comparison group of seventeen SRP nonparticipants, Group C, volunteered to undergo measurement of dehydroepiandrosterone-sulfate (DHEA-S), cortisol, DHEA-S/cortisol ratio, testosterone, apolipoprotein-A1, apolipoprotein-B, triglycerides, cholesterol, fibrinogen, and leukocyte count both before and after the SRP period. No differences in the changes in biochemical risk factors for CAD were found between participant and nonparticipant except for DHEA-S. While Group C had a marked reduction in DHEA-S levels, Group I had a small increase. Previous studies indicate DHEA-S is inversely associated with extent of CAD and age-adjusted DHEA-S levels below 3.78 mumol/l confer an increased risk for CAD mortality. SRP participation appears to effect DHEA-S levels, possibly partially accounting for the benefits observed in SRPs among CAD patients.

The influence of fitness on neuroendocrine responses to exhaustive treadmill exercise

Neuroendocrine and sympathoadrenal responses to exhaustive graded treadmill exercise were examined in 17 male subjects of varying degrees of fitness. The mean duration of exercise to exhaustion was 15.2 +/- 0.7 (+/- SE) min. Exercise duration was inversely correlated with baseline heart rate (P less than 0.05). Compared to standing baseline values, mean plasma norepinephrine and epinephrine levels increased 339% and 301%, respectively, in an integrated 2-min blood sample collected immediately after completion of exercise. Mean adrenocorticotrophic hormone (ACTH), beta-endorphin (beta-EP), beta-lipotropin (beta-LPH), and prolactin levels increased 282%, 720%, 372%, and 211%, respectively, in an integrated 4-min blood sample beginning 2 min after completion of exercise. Cortisol levels increased 183% in the sample collected 17-21 min after exercise. The magnitude of these neuroendocrine responses to exercise was similar among individuals at the same relative intensity of exhaustive exercise, regardless of the duration of exercise. The exercise-induced increases of the pro-opiomelanocortin (POMC)-derived peptides, ACTH, beta-EP, and beta-LPH, were highly correlated with each other (P values less than 0.001), and were correlated with prolactin increases, (P values less than 0.05). During a 20-min recovery period after exercise, changes in heart rate, ACTH, and beta-LPH levels were correlated with duration of exercise, (P less than 0.01, P less than 0.03, and P less than 0.03, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroendocrine responses to emotional stress: possible interactions between circulating factors and anterior pituitary hormone release

We have shown that a psychological stressor can elicit increases in plasma AVP levels in normal human subjects. Since AVP can enhance the release of ACTH, and the pituitary gland is outside the blood-brain barrier, AVP present in the general circulation might extend the time course of stress-induced, CRF-mediated release of ACTH from the anterior lobe. Since PRA is involved in the synthesis of angiotensin I, the precursor of AII, and AII is known to enhance CRF-mediated release of ACTH from pituitary cells and to stimulate release of AVP, it is possible that the increase in PRA also contributed to the release of AVP and ACTH in this study. Reports differ as to whether circulating catecholamines can release ACTH in vivo by direct action on the pituitary. Finally, it has been reported that beta-EP enhances the release of PRL, and inhibits release of AVP. Since the increase in beta-EP in the present study was quite robust, it might have extended the PRL release, and truncated the AVP response.

Effects of adrenalectomy on CRH regulation of ACTH release: adenylate cyclase activity, cyclic AMP-dependent protein kinase activity and ACTH release

Corticotropin releasing hormone (CRH) stimulation of ACTH release and cyclic AMP-mediated events involved in the control of ACTH release were compared in sham-operated and adrenalectomized rats. CRH-stimulated adenylate cyclase activity was decreased in pituitary homogenates from adrenalectomized animals. CRH-stimulated cyclic AMP accumulation was essentially abolished and CRH-stimulated cyclic AMP-dependent protein kinase (A-kinase) activity was decreased in freshly prepared anterior pituitary cells from adrenalectomized animals. Basal and CRH-stimulated ACTH release was elevated in these cells. Since ACTH release is increased in adrenalectomized rats despite the down regulation of CRH-linked pituitary mechanisms, we speculate that the site of action of disinhibition by corticosterone of ACTH release (or synthesis) following adrenalectomy is distal to the generation of cyclic AMP and/or that non-CRH mediated mechanisms assume a greater role in ACTH regulation following adrenalectomy.

Psychologic stress increases plasma levels of prolactin, cortisol, and POMC-derived peptides in man

Stressful social interactions have been shown to elicit increases in heart rate as well as in plasma levels of epinephrine, norepinephrine, and cortisol in humans. We sought to determine whether a competitive oral examination would affect plasma levels of the pituitary hormones ACTH, beta-endorphin, beta-lipotrophic hormone, and prolactin in a group of healthy young males. Seven min after beginning the examination, heart rate increased 27% and plasma levels of ACTH, beta-endorphin, beta-lipotropic hormone and prolactin rose 59%, 79%, 42%, and 46%, respectively, compared to values shortly before the examination. These hormone values returned to initial levels after the subjects returned to the waiting room. Plasma cortisol changes were similar in direction to those of ACTH but occurred about 15 min later. The present study demonstrates that a stressful social interaction can elicit rapid increases in plasma levels of the proopiomelanocortin derived peptide hormones and prolactin in man.

Effects of muscarinic pharmacophores on the cholinergic regulation of catecholamine secretion from perfused adrenal glands

The effects of the muscarinic antagonists, atropine, aprophen, azaprophen and pirenzepine, on catecholamine secretion stimulated by acetylcholine (ACh) and nicotine were studied using perfused and isolated guinea-pig adrenal glands. Sequential 2-min infusions of ACh (10(-5)M) at 15-min intervals evoked repetitive catecholamine secretory responses for at least 1 hr. This dose of ACh produced a predominantly muscarinic receptor-mediated catecholamine secretory response, which was inhibited by all muscarinic antagonists used. The order of potency was atropine greater than azaprophen greater than pirenzepine greater than aprophen, with IC50 values of 1.0 x 10(-9), 3.8 x 10(-9), 7.0 x 10(-8) and 1.3 x 10(-6) M, respectively. In comparison, repeated 1-min infusions of nicotine (2 x 10(-5) M) at 15-min intervals evoked progressively smaller catecholamine secretory responses over the course of 1 hr. At higher doses, atropine, azaprophen and aprophen also inhibited the nicotine-induced catecholamine secretion. In contrast, pirenzepine had no effect on the nicotinic response. The IC50 values for atropine, azaprophen and aprophen were 2.7 x 10(-6), 1.5 x 10(-6), and 3.2 x 10(-6) M, respectively. Because the antinicotinic effect of atropine and azaprophen was achieved at concentrations 2 to 3 orders of magnitude higher than those needed for the antimuscarinic effect, it was most likely not pharmacologically significant, but rather due to nonspecific inhibition of the nicotinic receptor.

Comparison of the effects of CRF and stress on levels of pituitary cyclic AMP and plasma ACTH in vivo

We have previously reported that acute stress increases levels of rat pituitary cyclic AMP in vivo. The present study was conducted to test the hypothesis that stress-induced increases in pituitary cyclic AMP in vivo were mediated via CRF. We compared the effects of various stressors with the effects of CRF or epinephrine administration on pituitary cyclic AMP and plasma ACTH responses in vivo. Stressors, epinephrine or CRF increased levels of pituitary cyclic AMP. Pituitary cyclic AMP response to either immobilization or CRF was much greater at light onset than at lights off in rats maintained on a 12 hr light:12 hr dark lighting regimen. In rats with pituitary stalk transections, footshock did not increase levels of pituitary cyclic AMP, suggesting that some factor of central origin was required for this stress response. Exogenous CRF administration did increase levels of pituitary cyclic AMP in stalk-transected rats, while epinephrine increased levels in sham-operated but not in stalk-transected rats. Antisera to CRF markedly decreased pituitary cyclic AMP response to exogenous CRF administered 6 min following antisera and partially attenuated pituitary cyclic AMP response to forced running. Taken as a whole these data support a major role for CRF in the pituitary cyclic AMP response to stress.

Subsensitive pituitary cyclic AMP response to stress following adrenalectomy is not caused by loss of adrenal epinephrine

We have previously reported that various stressors acutely elevate levels of pituitary cyclic AMP in vivo and that this stress response is not seen in animals tested 7 or 30 days post-adrenalectomy. In this report we present data that demonstrate that the loss of the pituitary cyclic AMP stress response following adrenalectomy is not the result of the loss of stress-induced adrenal epinephrine release. These data show that (1) although administration of epinephrine to intact rats does not elevate levels of pituitary cyclic AMP, administration of epinephrine to adrenalectomized animals does not elevate pituitary cyclic AMP levels in vivo; (2) splanchnic denervation prevents stress-induced adrenal epinephrine release but does not abolish stress-induced increases in pituitary cyclic AMP; and (3) the time course of the developing subsensitive pituitary cyclic AMP response to stress following adrenalectomy is much slower (2 to 3 days) than the loss of circulating epinephrine.