Sildenafil, Viagra/Revatio
Description: Phosphodiesterase-5-Inhibitor
CSA NA – FDA Approved – REMS (N) – Can Ship
How Does It Work
Sildenafil/Viagra/Revatio enhances the physiological erectile response following sexual arousal through the potentiation of nitric oxide effects on vascular smooth muscle. Nitric oxide is released into the corpus cavernosum in response to sexual stimulation. This stimulates the production of cGMP, leading to smooth muscle relaxation and subsequently vasodilation and erection of the penis. Sildenafil/Viagra/Revatio selectively inhibits cGMP for PDE5 which is the main enzyme that metabolizes cGMP in the penis, thus enhancing the erectile response of the penis.
Indications For Use
Sildenafil/Viagra/Revatio is indicated for the treatment of erectile dysfunction or organic, psychogenic, or mixed etiology
Precautions
Use with caution or avoid in persons with increased susceptibility to vasodilators including those with aortic stenosis, cardiomyopathy, and impaired autonomic control of blood pressure.
Use with caution in persons who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last six months.
Use with caution in persons with resting hypotension (blood pressure under 90/50) or hypertension (blood pressure 170/110).
Use with caution in persons with heart failure or coronary artery disease.
Usual Dosing
Erectile dysfunction – Sildenafil/Viagra/Revatio
Take 50mg once daily as needed; can be taken 1 to 4 hours before sexual activity. Reduce the dose down to 25mg if you experience any side effects. May increase the dose to a maximum daily dose of 100mg if not satisfied with the erectile response to sexual stimulation.
High-altitude pulmonary edema – Sildenafil/Viagra/Revatio
Prevention: May use Sildenafil/Viagra/Revatio as an adjunct therapy during gradual ascent in high-risk individuals (i.e. history of high-altitude pulmonary edema).
Take 50mg every 8 hours starting the day of ascent and continue for 3 to 5 days after reaching the maximal altitude.
Pulmonary artery hypertension – Sildenafil/Viagra/Revatio
Take 20mg every 8 hours. Can slowly increase the dose in 20mg increments to a maximum dose of 80mg every 8 hours daily.
Raynaud’s disease – Sildenafil/Viagra/Revatio
Take 20mg once to twice daily; may increase to 20mg three times daily if the lower doses are ineffective.
Points To Consider
Pros
Significantly improves the achievement and maintenance of an erection during intercourse
Improves overall sexual satisfaction
Improves orgasmic function
Cons
Mild and transient side effects
Slower onset of action compared to injected or transurethral modes of delivery
Limited efficacy was seen following radical prostatectomy
Contraindicated if you are using organic nitrates in any form due to additive hypotensive effects
Should be used with caution in individuals who have had a myocardial infarction, stroke, or life-threatening arrhythmia within the last six months
Pharmacist Tips On Using
How to Take (Sildenafil/Viagra/Revatio): Do not split the tablet; take the entire tablet and swallow whole on an empty stomach. When used as needed, take at least 60 minutes prior to sexual activity.
You Need to Avoid (Sildenafil/Viagra/Revatio): avoid large amounts of grapefruit and its juice (CYP3A4 inhibitor) and alcohol which may enhance the hypotensive effect.
If You Experience Chest Pain (Sildenafil/Viagra/Revatio): Seek medical attention immediately.
If You Experience Hearing Loss (Sildenafil/Viagra/Revatio): If you experience a sudden decrease or loss in hearing. Seek medical attention.
If Your Penile Erection Does Not Go Down (Sildenafil/Viagra/Revatio): Painful erections lasting > 6 hours is known as priapism and is rare. However, if your erection lasts longer than > 4 hours, seek medical condition. Certain medical conditions such as sickle cell anemia, multiple myeloma and leukemia have been associated with a higher risk of priapism.
If You Experience Vision Loss (Sildenafil/Viagra/Revatio): Vision loss is rare but may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION). Please seek medical attention immediately for any sudden loss of vision in one or both eyes. Risk factors for NAION include coronary artery disease (CAD), diabetes, hypertension, hyperlipidemia, smoking and > 50 years of age.
Side Effects
Well tolerated, most side effects are transient and mild to moderate in nature. However, adverse effects such as flushing, diarrhea, myalgia and visual disturbances can increase with doses greater than 100mg every 24 hours. The most common side effects include:
>10%
Cardiovascular: Flushing (10% to 19%)
Central Nervous System: Headache (16% to 46%)
Gastrointestinal: Dyspepsia (3% to 17%)
Ophthalmic: Visual disturbances (2% to 11%; including vision colour changes, blurred vision, and photophobia)
Respiratory: Epistaxis (9% to 13%)
Frequently Asked Questions
Do you take Sildenafil/Viagra/Revatio with food or on an empty stomach?
Take Viagra, Revatio/Sildenafil without food on an empty stomach.
Can you drink alcohol when you are on Sildenafil/Viagra/Revatio?
You should limit or completely avoid alcohol consumption when taking Viagra, Revatio/Sildenafil as the alcohol can increase the risk of symptomatic hypotension leading to dizziness and potentially cardiovascular collapse.
Can Sildenafil/Viagra/Revatio cause spontaneous erections?
No is the short answer. Viagra, Revatio/Sildenafil does not directly cause penile erections but rather affects the penile response to sexual stimulation. Viagra, Revatio/Sildenafil inhibits the enzyme phosphodiesterase type 5 (PDE-5) which is responsible for the breakdown of cGMP in the corpus cavernosum of the penis. During sexual stimulation, there is a local increase in nitric oxide, inhibition of PDE-5 by Viagra, Revatio/Sildenafil will lead to increased levels of cGMP and subsequently smooth muscle relaxation around the blood vessels resulting in a significant increase in blood flow into the corpus cavernosum of the penis.
Bottom line if you are not experiencing sexual stimulation there will be no penile erection.
How fast does Sildenafil/Viagra/Revatio work?
Sildenafil has an onset of action within 1 hour.
Can Sildenafil/Viagra/Revatio cause a painful erection?
Yes, a condition known as priapism which refers to an erection lasting longer than 6 hours has been reported but only rarely. Anytime you experience any erection lasting > 4 hours, seek medical attention immediately.
Can women use Sildenafil/Viagra/Revatio for sexual dysfunction?
There have been a couple of studies investigating the use of phosphodiesterase inhibitors such as Cialis and Viagra in women reporting mixed inconsistent results. The best available evidence comes from a randomized trial in women suffering from sexual disorders of desire, arousal, orgasm, and dyspareunia treated with Viagra, Revatio/Sildenafil for 12 weeks. They found that Viagra, Revatio/Sildenafil was not more effective than placebo in terms of improving any aspect of sexual function. However, positive effects were reported on sexual arousal and orgasm in premenopausal women with SSRI-associated sexual dysfunction.
What works better Cialis, Viagra, or Levitra?
There is no evidence to suggest which phosphodiesterase-5-inhibitor works best. There are some special circumstances where one may be preferred over another. Cialis, Viagra, and Levitra all work the same, however, the duration of action of Cialis is up to 36 hours compared to 24 hours for Viagra and Levitra. The adverse effect profile is similar for all drugs with a few exceptions. Cialis and Levitra have a considerably reduced frequency of visual colour distortions compared to Sildenafil. Cialis and Levitra are not recommended in patients who renal and/or hepatic impairment.