There are several medications on the market whose purpose is to treat the erectile dysfunction in men. In the last couple of years three of them have stood out
because of their good effects and they are Levitra, Cialis and Viagra. They all have some advantages and flaws and you have to decide which one would suit you best.
Levitra%26reg;
Levitra%26reg; is an FDA-approved oral prescription medication for the treatment of erectile dysfunction in men. It is available in 2.5-mg, 5-mg, 10-mg, and 20-mg tablets and is taken only when needed.
Mechanism of action
Penile erection is in fact a specific hemodynamic process initiated by the relaxation of the smooth muscle in the corpora cavernosa - erectile parts of the penis. During sexual stimulation, nitric oxide is released from nerve endings which then activates the enzymes resulting in increased synthesis of cyclic guanosine monophosphate smooth muscle cells of the corpora cavernosa. This substance triggers smooth muscle relaxation, allowing an increased blood flow into the penis, resulting in erection.
The main regulators of tissue concentration of cGMP are phosphodiesterases and the main ingredient of Levitra%26reg; is the cGMP-specific phosphodiesterase type 5.
Levitra effects
Several studies have been conducted on the Levitra%26reg; effects and side effects and most of the studies have shown that:
%26bull; Levitra%26reg; helps increase blood flow to the penis, so it may help men with erectile dysfunction and keep an erection that lasts long enough to finish having sex.
%26bull; Once a man has completed sexual activity, the blood flow to his penis decreases and his erection should go away
%26bull; Levitra%26reg; provided the first-time success and reliable improvement of erection quality in most men including those with high cholesterol, high blood pressure, or diabetes
%26bull; Men taking Levitra%26reg; had harder erections and greater success at maintaining their erections long enough to finish having sex
Levitra indications
%26bull; Works for many men with other health conditions, including high cholesterol
%26bull; It may be used by those taking one or more types of blood pressure medication
%26bull; Works for many men with type 1 or type 2 diabetes, across all levels of ED severity
%26bull; May work when other oral treatments do not
Levitra contraindications
%26bull; Nitrates
Administration of Levitra%26reg; with nitrates and nitric oxide donors is contraindicated.
A suitable time interval following Levitra usage for the safe administration of nitrates or nitric oxide donors has not been determined.
%26bull; Hypersensitivity
This medication is contraindicated for patients with a known hypersensitivity to any component of the tablet.
WARNINGS
%26bull; Cardiovascular effects General
Physicians should consider the cardiovascular status of their patients, since there is a degree of cardiac risk associated with sexual activity. In men for whom sexual activity is not recommended because of their underlying cardiovascular status, any treatment for erectile dysfunction, including Levitra, generally should not be used.
%26bull; Left Ventricular Outflow Obstruction
It is proven that patients with left ventricular outflow obstruction could be sensitive to the action of vasodilators including Type 5 phosphodiesterase inhibitors.
%26bull; Blood Pressure Effects
Levitra%26reg; is systemic vasodilator which results in decreases in blood pressure in healthy people. While this normally would be expected to be of little consequence in most patients, it may present a problem in patients with underlying cardiovascular disease.
%26bull; Other Effects
There have been rare reports of prolonged erections greater than 4 hours and painful erections greater than 6 hours in duration. In the event that an erection persists longer than 4 hours, the patient should seek immediate medical assistance.
Cialis%26reg; %26ndash; The %26ldquo;weekend pill%26rdquo;
Cialis (Tadalafil%26reg;) is another drug used to treat male erectile dysfunction. In the United States, Tadalafil has FDA approval and became available in December, 2003 as the third pill after Viagra%26reg; and Levitra%26reg;. This pill is famous due to its 36-hour effect. That%26rsquo;s why it is also known as the %26quot;Weekend Pill%26quot;.
Chemically it is almost identical to Levitra%26reg; because it also belongs to the group of medications called selective inhibitors of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).
Drug interactions
%26bull; organic nitrates
Because it is proven that PDE5 inhibitors such as Tadalafil may cause low blood pressure, it is recommended that organic nitrates should not be taken for at least 48 hours after taking the last dose of Tadalafil%26reg;. It is proven that using organic nitrates within this time frame may increase the risk of life-threatening hypotension.
Possible side effects of Cialis%26reg;
Research has shown that several side effects can occur from using Cialis%26reg;. Some of the most common are:
%26bull; an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
%26bull; chest pain or irregular heartbeats;
%26bull; dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw);
%26bull; swelling of the ankles or legs;
%26bull; shortness of breath;
%26bull; prolonged or severe dizziness; or
%26bull; a prolonged (lasting longer than 4 hours) or painful erection
Other, less serious side effects which are more likely to occur are:
%26bull; headache;
%26bull; indigestion;
%26bull; back pain;
%26bull; muscle aches;
%26bull; flushing;
%26bull; stuffy or runny nose; or
%26bull; temporary blue tint in vision or difficulty telling the difference between the colors blue and green.
Viagra%26reg;
Viagra%26reg; or Sildenafil citrate is a drug used to treat male erectile dysfunction and pulmonary arterial hypertension.
Viagra%26reg; pills are blue and diamond-shaped with the words %26quot;Pfizer%26quot; on one side.
Mechanism of action
A substance called nitric oxide binds to the receptors of the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate, leading to smooth muscle relaxation in the corpus cavernous. This is resulting in increased inflow of blood in the penis and an erection.
Similar to Cialis%26reg; and Levitra%26reg;, Viagra%26reg; is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernous. This is resulting in better erections. Sildenafil is metabolized by hepatic enzymes and excreted by both the liver and kidneys.
Contraindications and side effects
Contraindications include:
%26bull; When taking nitric oxide donors, organic nitrites and nitrates, such as glyceryl trinitrate, and other similar medications
%26bull; In men for whom sexual intercourse is inadvisable due to cardiovascular risk factors
%26bull; Severe liver damage
%26bull; Severe impairment in renal function
%26bull; Low blood pressure
%26bull; Recent stroke or heart attack
%26bull; Hereditary degenerative retinal disorders
Common side effects include sneezing, headache, flushing, dyspepsia, prolonged erections, palpitations and photophobia.
Viagra%26reg; and Pulmonary hypertension
Viagra is also effective in a rare disease called pulmonary arterial hypertension. Several researches have proven that this medication relaxes the arterial wall, decreasing pulmonary arterial resistance and pressure, and reduces the strain on the right side of the heart thus improving symptoms of right-sided heart failure.
Viagra%26reg; and Raynaud's phenomenon
Several experts in this field have recently reported that Viagra cuts the frequency of Raynaud's phenomenon attacks. Viagra reduced their duration by roughly one half, and more than quadrupled the mean capillary blood velocity. This attacks are related to oversensitivity to cold.
Viagra%26reg; and cognitive enhancement
Several recent studies showed that Viagra%26reg; may help reduce and relieve cognitive deficits associated with aging. Although mechanism of this still isn't known, scientists found that in rats, administration of Viagra partially reversed the memory impairment.
Viagra%26reg; and Analgestic properties
Several studies have determined that Viagra demonstrates anti-nociceptive or pain-relieving properties in rodents. Current evidence seems to suggest that the cGMP that accumulates as a result of Phosphodiesterase 5 inhibition interacts with the cholinergic system to mediate this pain-reducing effect.
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