Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Since then, several other oral PDE-5 inhibitors have been developed, including vardenafil and tadalafil, which generated considerable interest in both the scientific and lay communities. There was also much concern about their safety, especially in men with cardiovascular disease. Compared with the 2 newer PDE-5 inhibitors vardenafil and tadalafil, sildenafil has been available for a much longer time; therefore, the vast majority of published cardiovascular safety studies have been performed on this medication. Recommended starting and maximum doses of oral PDE-5 inhibitors are shown in Table 1.
Several drugs can produce erectile difficulties, but blood pressure drugs are near the top. ED is an occasional side effect of BP drugs like thiazide diuretics, loop diuretics, and beta-blockers, all of which can decrease blood flow to the penis and make it difficult to get an erection. However, other BP drugs, such as alpha-blockers, ACE inhibitors, and angioten-sin-receptor blockers, rarely cause ED.
Relation between erectile dysfunction prevalence and type of coronary syndrome (A). Time interval (months) between erectile dysfunction and coronary artery disease symptom onset in chronic coronary syndrome according to the number of vessels involved (B). ACS, acute coronary syndrome; CCS, chronic coronary syndrome, G1: ACS and 1-VD; G2: ACS and 2-,3-VD; G3: CCS. VD, vessel disease; C: the control group with normal coronary angiography. With permission from Montorsi et al.15
Cardiovascular tolerance for sex is based on “functional reserve,” which corresponds to how closely the cardiovascular response to sex (in terms of heart rate, blood pressure level, and oxygen consumption) approaches the patient's peak response to exercise.85x85DeBusk, RF. Evaluating the cardiovascular tolerance for sex. Am J Cardiol. 2000; 86: 51F–56F
In men without cardiovascular disease, erectile dysfunction (ED) pills are very safe. The three rivals -- Viagra, Cialis, and Levitra -- have similar side effects, including headache, facial flushing, nasal congestion, diarrhea, backache, and, in a few Viagra or Levitra users, temporary impaired color vision (men with retinitis pigmentosa, a rare eye disease, should check with their ophthalmologists before using these medications).
"We think that if you have an active sex life it's probably an indicator of a healthy lifestyle, especially in the oldest quartile—those 70 to 80 years old," Andersson said. "From the perspective of a doctor, if a patient asks about erectile dysfunction drugs after a heart attack and has no contraindications for PDE5 inhibitors, based on these results you can feel safe about prescribing it."

Having chronically high blood pressure can affect overall satisfaction with sex and affect men’s ability to achieve a firm erection. Due to constant vessel damage as a result of high blood pressure, linings of the arteries begin to harden and narrow, a process called atherosclerosis. Because blood flow is limited to the affected regions of the body, arterial blood circulation to various organs—including the heart muscles, brain, and even the groin—can be compromised, with myocardial infarctions, strokes, and erectile difficulty being common in hypertensive patients. Studies show that approximately 30 percent of hypertensive patients reported having erectile dysfunction, and approximately 49 percent of men aged 40 to 79 had both high blood pressure and ED.
Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (30) | Google ScholarSee all References Erections result from relaxation of the corpora cavernosa, which is mediated either by increasing intracellular cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate or by inhibition of their degradation. Increased parasympathetic tone results in a decrease in norepinephrine release and an increase in the release of acetylcholine; subsequently, NO synthase activity increases, which releases NO from both endothelial cells and nonadrenergic, noncholinergic neurons.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
More than 11 million people in the United States have cardiovascular disease, and each year, about 500,000 survive a myocardial infarction. These patients often seek counseling on their relative risk of resuming sexual activity. In the past, it was often assumed that if a patient could climb 2 flights of stairs without symptoms, it was safe for the patient to engage in sexual activity.82x82Hellerstein, HK and Friedman, EH. Sexual activity and the postcoronary patient. Arch Intern Med. 1970; 125: 987–999
Crossref | PubMed | Scopus (72) | Google ScholarSee all References This study found that the mean PSV was a better predictor of the presence of cardiovascular disease than stratification by standard cardiac risk factors such as diabetes mellitus, hypertension, obesity, and smoking. The researchers recommended that persons with no history of prior perineal trauma and with a PSV lower than 35 mL/s should undergo exercise testing before receiving treatment of ED because these patients had a 42% risk of having ischemic heart disease. However, other investigators questioned the utility of using penile arterial flow to predict the presence of ischemic heart disease.18x18Chiu, AW, Chen, KK, Chen, MT, Chang, LS, and Chang, MS. Penile brachial index in impotent patients with coronary artery disease. Eur Urol. 1991; 19: 213–216
Crossref | PubMed | Scopus (23) | Google ScholarSee all References, 73x73Rajagopalan, P, Mazzu, A, Xia, C, Dawkins, R, and Sundaresan, P. Effect of high-fat breakfast and moderate-fat evening meal on the pharmacokinetics of vardenafil, an oral phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction. J Clin Pharmacol. 2003; 43: 260–267
Erectile dysfunction means that a man is not able to have sex because he cannot get or keep an erection. Erectile dysfunction affects >30% of men between 40 and 70 years of age. There are several different causes of ED, including depression, low testosterone, nerve problems, and some medications, but the most common cause is a problem with the blood vessels called atherosclerosis.
Oral medicines: The best known ED medications are the Big Three: Viagra (sildenafil citrate, made by Pfizer, Inc.), Levitra (vardenafil HCl, made by Bayer and GlaxoSmithKline), and Cialis (tadalafil, made by Eli Lilly). The three are chemically very similar, and all have proven very effective. Because they are effective, convenient, and relatively inexpensive (about nine dollars per pill), these medicines have become the treatment of choice for most men experiencing ED.

The views expressed in this article intend to highlight alternative studies and induce conversation. They are the views of the author and do not necessarily represent the views of hims, and are for informational purposes only, even if and to the extent that this article features the advice of physicians and medical practitioners. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice.
Table 3 is a suggested algorithm for the assessment of patients and their further categorization and handling. There are parts of investigation that are common for patients both with and without CVD, while additional elements of investigation are helpful in categorizing the patient without CVD to the appropriate risk category. Determination of exercise ability and stress testing is crucial to the assessment (see also below ‘Exercise ability: the risk of sexual activity’). Patients without established CVD or diabetes should be evaluated for their risk of future events according to risk scores (SCORE or Framingham). Patients with established CVD or diabetes are by default considered at increased risk. Patients with adequate exercise ability or a negative stress test can initiate or resume sexual activity and begin treatment for ED. In patients with a positive stress test or in high-risk patients, sexual activity should be deferred until the cardiac condition has been treated and stabilized. In all cases, patient follow-up and reassessment is recommended.

Getting frequent exercise and maintaining a healthy weight are, of course, also important. Plus, avoiding or minimizing risky dietary factors such as salt, alcohol, caffeine, and too much animal products is crucial. Animal protein elevates insulin-like growth factor 1 (IGF-1) in the blood, a growth-promoting hormone that is associated with increased risk of several cancers and cardiovascular disease.19, 20
ED can be caused by many things. The most common causes in men with diabetes are problems related to blood vessel– and nerve-related complications. Sometimes, though rarely, ED can be caused by a hormonal imbalance. Depression can also cause ED, as can stress and excessive worrying about sexual performance. Certain medications can cause temporary ED.
"We think that if you have an active sex life it's probably an indicator of a healthy lifestyle, especially in the oldest quartile—those 70 to 80 years old," Andersson said. "From the perspective of a doctor, if a patient asks about erectile dysfunction drugs after a heart attack and has no contraindications for PDE5 inhibitors, based on these results you can feel safe about prescribing it."
Since their introduction in the therapeutic field, more than a decade ago, PDE-5 inhibitors have revolutionized the treatment of sexual dysfunction. By blocking the activity of PDE-5 isoenzyme, localized throughout the smooth muscle cells of the vasculature (genital vessels included), PDE-5 inhibitors increase the levels of cyclic guanosine monophosphate thus exerting vasodilating properties and facilitating penile erection[40-42]. Due to these properties, sildenafil was the first drug of its class to receive wide acceptance. Its short half-life, food interactions and the associated visual disturbances however, paved the way for the development of newer PDE-5 inhibitors. As such vardenafil with its more rapid onset of action, and tadalafil with its longer half-life and the lack of food interactions or side effects, have offered significant alternatives to sildenafil[43-50].
A man needs to try the medicine at least four times before he concludes that it doesn’t work for him. It is unlikely that a man with diabetes who has other medical problems such as high blood pressure, is taking multiple medicines, and has not had sexual intercourse for several years will be able to have an erection adequate for intercourse the first time he takes a pill. Most men need to try the medicine several times before they have the desired results.
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