Sexual response drug effects

CS3 50 Saso, L. Effects of drug abuse on sexual response. Ann 1st Super Sanita 2002 ... 

Intracavernosal alprostadil was effective and well tolerated in the treatment of erectile dysfunction, according to the results of a 6-month study (funded by Pharmacia Upjohn) in 848 men (mean age 52 years) with at least a 4-month history of erectile dysfunction (12). This is provided that the individual dose is established by titration and patients receive training in injection techniques and periodic supervision during treatment. An initial dose was established for each patient and the patients then administered the alprostadil themselves at home. Of 727 evaluable patients, 682 (94%) had at least one erectile response after the injection of alprostadil, and 88% of injections lead to a satisfactory sexual response. The most commonly reported adverse event was penile pain, reported by 44% of patients, but only after 8% of injections. In just over half of the patients who had penile pain, the condition was reported as mild. Prolonged erection, penile fibrosis, and priapism occurred in 8,4, and 0.9% of patients respectively. Treatment was withdrawn because of medical events in 4% of patients, and drug-related events accounted for treatment withdrawal in 2% of patients. 

In the presence of sexual stimulation and in doses of 25 to 100 mg, sildenafil produces satisfactory erections in 56% to 82% of patients, independent of the etiology of erectile dysfunction. Similar values are documented in the product labeliug for the other two agents in this class (65% to 80% for vardenafll and 62% to 77% for tadalafil). Response rates for sUdenafll in the lower range have been documented in patients following radical prostatectomy, probably due to postoperative nerve damage. The drugs effectiveness appears to be dose related. °... 

Nicotine is an addictive substance with rewarding and reinforcing properties. On the other hand, the autonomic responses following an acute nicotine treatment and the bitter taste of nicotine may cause aversion. This aversion may impact conditioned effects to nicotme. Rinker et al. (2008) studied possible sex differences in taste aversion mduced by nicotine in rats systemic nicotine or saline injections were paired wim oral saccharine. Although nicotme did produce a weak taste aversion, no sex differences were observed, excluding the possible contribution of the aversive properties of nicotine on sexually dimorphic responses to nicotine. The authors conclude that sex differences may arise from differences in the rewardmg properties of the drug. 

The mechanisms by which thiazides affect erectile dysfunction or libido are unclear, but it has been suggested that they have a direct effect on vascular smooth muscle cells or reduce the response to catecholamines. Sexual dysfunction does not appear to be mediated by either a low serum potassium concentration or a low blood pressure. Since sexual dysfunction can adversely affect the quality of life of hypertensive patients, physicians or health-care providers should take an accurate baseline sexual history and monitor sexual status for changes during therapy. If there are significant changes in sexual function, diuretic therapy can be withdrawn and an alternative drug class substituted. However, not uncommonly sexual dysfunction will persist despite withdrawal of the diuretic, suggesting that elements of the hj pertensive state itself contribute to the process. 

Tyramine present in certain food and beverages can displace NE from sympathetic nerve endings, causing CV stimulation, but only if its metabolism is inhibited by MAO inhibitors. Patients suffering from HTN commonly discontinue medications (without physician consultation) based on perceived undesirable side effects, such as sexual dysfunction. In the case of clonidine, rebound hypertension and tachycardia, especially with abrupt discontinuance, can be problematic. Discontinuance of thiazide is likely to result in fluid retention with weight gain and unlikely to cause tachycardia and marked increase in BP. Ethanol is an effective vasodilator and tends to decrease BP. Tachyphylaxis refers to the development of a decreased response to drug treatment over a time span of minutes to hours, not years. 

The major adverse effects of clonidine are dry mouth and sedation. These responses occur in at least 50% of patients and may require dmg discontinuation. However, they may diminish in intensity after several weeks of therapy. Sexual dysfunction also may occur. Marked bradycardia is observed in some patients. These and some of the other adverse effects of clonidine frequently are related to dose, and their incidence may be lower with transdermal administration of clonidine because antihypertensive efficacy may be achieved while avoiding the relatively high peak concentrations that occur after oral administration of the drug. About 15 to 20% of patients develop contact dermatitis when using clonidine in the transdermal system. Withdrawal reactions follow abrupt discontinuation of long-term therapy with clonidine in some hypertensive patients. 

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