Cardiovascular stimulant actions of bupropion in comparison to cocaine in the rat

Understanding and treating ejaculatory dysfunction in men with diabetes mellitus

Diabetes mellitus is a rapidly rising metabolic disorder with important systemic complications. Global figures have demonstrated the prevalence of diabetes mellitus has almost quadrupled from 108 million in 1980 to 422 million in 2014, with a current prevalence of over 525 million. Of the male sexual dysfunction resulting from diabetes mellitus, significant focus is afforded to erectile dysfunction. Nevertheless, ejaculatory dysfunction constitutes important sexual sequelae in diabetic men, with up to 35%-50% of men with diabetes mellitus suffering from ejaculatory dysfunction. Despite this, aspects of its pathophysiology and treatment are less well understood than erectile dysfunction. The main disorders of ejaculation include premature ejaculation, delayed ejaculation, anejaculation and retrograde ejaculation. Although ejaculatory dysfunction in diabetes mellitus can have complex multifactorial aetiology, understanding its pathophysiological mechanisms has facilitated the development of therapies in the management of ejaculatory dysfunction. Most of our understanding of its pathophysiology is derived from diabetic animal models; however, observational studies in humans have also provided useful information in elucidating important associative factors potentially contributing to ejaculatory dysfunction in diabetic men. These have provided the potential for more tailored treatment regimens in patients depending on the ejaculatory disorder, other co-existing sequelae of diabetes mellitus, specific metabolic factors as well as the need for fertility treatment. However, evidence for treatment of ejaculatory dysfunction, especially delayed ejaculation and retrograde ejaculation, is based on low-level evidence comprising small sample-size series and retrospective or cross-sectional studies. Whilst promising findings from large randomised controlled trials have provided strong evidence for the licensed treatment of premature ejaculation, similar robust studies are needed to accurately elucidate factors predicting ejaculatory dysfunction in diabetes mellitus, as well as for the development of pharmacotherapies for delayed ejaculation and retrograde ejaculation. Similarly, more contemporary robust data are required for fertility outcomes in these patients, including methods of sperm retrieval and assisted reproductive techniques in retrograde ejaculation.

Pharmacology of Drugs Used as Stimulants

Psychostimulant, cardiovascular, and temperature actions of stimulants involve adrenergic (norepinephrine), dopaminergic (dopamine), and serotonergic (serotonin) pathways. Stimulants such as amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), or mephedrone can act on the neuronal membrane monoamine transporters NET, DAT, and SERT and/or the vesicular monoamine transporter 2 to inhibit reuptake of neurotransmitter or cause release by reverse transport. Stimulants may have additional effects involving pre- and postsynaptic/junctional receptors for norepinephrine, dopamine, and serotonin and other receptors. As a result, stimulants may have a wide range of possible actions. Agents with cocaine or MDMA-like actions can induce serious and potentially fatal adverse events via thermodysregulatory, cardiovascular, or other mechanisms. MDMA-like stimulants may cause hyperthermia that can be life threathening. Recreational users of stimulants should be aware of the dangers of hyperthermia in a rave/club environment.

Cardiovascular and temperature adverse actions of stimulants

The vast majority of illicit stimulants act at monoaminergic systems, causing both psychostimulant and adverse effects. Stimulants can interact as substrates or antagonists at the nerve terminal monoamine transporter that mediates the reuptake of monoamines across the nerve synaptic membrane and at the vesicular monoamine transporter (VMAT-2) that mediates storage of monoamines in vesicles. Stimulants can act directly at presynaptic or postsynaptic receptors for monoamines or have indirect monoamine-mimetic actions due to the release of monoamines. Cocaine and other stimulants can acutely increase the risk of sudden cardiac death. Stimulants, particularly MDMA, in hot conditions, such as that occurring at a "rave," have caused fatalities from the consequences of hyperthermia, often compounding cardiac adverse actions. This review examines the pharmacology of the cardiovascular and temperature adverse actions of stimulants.

Cardiovascular effects of antiobesity drugs: are the new medicines all the same?

Waiting for a definite answer from well-designed randomized prospective clinical trials, the impact of the new antiobesity drugs -liraglutide, bupropion/naltrexone, phentermine/topiramate and lorcaserin- on cardiovascular outcomes remains uncertain. What has been learned from previous experience with older medicines is that antiobesity drugs may influence cardiovascular health not only causing weight reduction but also through direct actions on the cardiovascular system. Therefore, in the present review, we examine what is known, mainly from preclinical investigations, about the cardiovascular pharmacology of the new antiobesity medicines with the aim of highlighting potential mechanistic differences. We will show that the two active substances of the bupropion/naltrexone combination both exert beneficial and unwanted cardiovascular effects. Indeed, bupropion exerts anti-inflammatory effects but at the same time it does increase heart rate and blood pressure by potentiating catecholaminergic neurotransmission, whereas naltrexone reduces TLR4-dependent inflammation and has potential protective effects in stroke but also impairs cardiac adaption to ischemia and the beneficial opioid protective effects mediated in the endothelium. On the contrary, with the only exception of a small increase in heat rate, liraglutide only exerts favorable cardiovascular effects by protecting myocardium and brain from ischemic damage, improving heart contractility, lowering blood pressure and reducing atherogenesis. As far as the phentermine/topiramate combination is concerned, no direct cardiovascular beneficial effect is expected for phentermine (as this drug is an amphetamine derivative), whereas topiramate may exert cardioprotective and neuroprotective effects in ischemia and anti-inflammatory and antiatherogenic actions. Finally, lorcaserin, a selective 5HT_2C receptor agonist, does not seem to exert significant direct effects on the cardiovascular system though at very high concentrations this drug may also interact with other serotonin receptor subtypes and exert unwanted cardiovascular effects. In conclusion, the final effect of the new antiobesity drugs on cardiovascular outcomes will be a balance between possible (but still unproved) beneficial effects of weight loss and "mixed" weight-independent drug-specific effects. Therefore comparative studies will be required to establish which one of the new medicines is more appropriate in patients with specific cardiovascular diseases.

The drug treatment of delayed ejaculation

Delayed ejaculation (DE) is an uncommon and a challenging disorder to treat. It is often quite concerning to patients and it can affect psychosocial well-being. Here we reviewed how DE is treated pharmacologically .We also highlighted specific settings where drugs could be introduced to medical practice. Electronic databases were searched from 1966 to February 2016, including PubMed MEDLINE, EMBASE, EBCSO Academic Search Complete, Cochrane Systematic Reviews Database, and Google Scholar using key words; delayed ejaculation, retarded ejaculation, inhibited ejaculation, drugs, treatment, or pharmacology. To achieve the maximum sensitivity of the search strategy and to identify all studies, we combined “delayed ejaculation” as Medical Subject Headings (MeSH) terms or keywords with each of “testosterone” or “cabergoline” or “bupropion” or “amantadine” or “cyproheptadine” or “midodrine” or “imipramine” or “ephedrine” or “pseudoephedrine” or “yohimbine” or “buspirone” or “oxytocin” or “bethanechol” as MeSH terms or keywords. There are a number of drugs to treat patients with DE including: testosterone, cabergoline, bupropion, amantadine, cyproheptadine, midodrine, imipramine, ephedrine, pseudoephedrine, yohimbine, buspirone, oxytocin, and bethanechol. Although there are many pharmacological treatment options, the evidence is still limited to small trials, case series or case reports. Review of literature showed that evidence level 1 (Double blind randomized clinical trial) studies were performed with testosterone, oxytocin, buspirone or bethanechol treatment. It is concluded that successful drug treatment of DE is still in its infancy. The clinicians need to be aware of the pathogenesis of DE and the pharmacological basis underlying the use of different drugs to extend better care for these patients. Various drugs are available to address such problem, however their evidence of efficacy is still limited and their choice needs to be individualized to each specific case.

Naltrexone HCI/bupropion HCI for chronic weight management in obese adults: patient selection and perspectives

Naltrexone, an opiate antagonist, and bupropion, a noradrenergic/dopaminergic antidepressant, have many effects on the reward systems of the brain. These medications impact eating behavior, presumably via their impact on food reward. However, only bupropion induces weight loss in obese individuals, while naltrexone does not have any appreciable effect. The combination of 32 mg of naltrexone and 360 mg of bupropion in a sustained-release combination pill form has been recently approved for obesity treatment. Studies have shown that the combination of these two medications is more effective in inducing weight loss, when combined with lifestyle intervention and calorie reduction, than each individual medicine alone. The naltrexone-bupropion combination, when combined with lifestyle intervention and modest calorie reduction, seems to be quite effective for 6-month and 1-year outcomes for clinically significant weight loss (over 5% of total body weight). These medications are not devoid of serious side effects, however, and careful patient selection can reduce dramatic complications and increase positive outcomes. This paper reviews existing weight loss clinical trials with bupropion and the bupropion-naltrexone combination. Additionally, the rationale for the suggested patient selection and clinical strategies for special patient populations are discussed.