Sildenafil isn’t recommended for people with pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis.

• Sildenafil is available in different strengths to tailor treatment.
• It is often used in clinical settings for ED diagnosis and management.
• Men taking sildenafil should avoid heavy meals shortly before dosing.
• The drug's effectiveness can be influenced by age and overall health.
• Combining sildenafil with recreational drugs can be dangerous.
• Some users report that sildenafil enhances spontaneous sexual activity.
• It is important to only use sildenafil that has been prescribed by a healthcare provider.
• The medication’s cost varies based on brand, dosage, and pharmacy.
• Sildenafil may cause transient eye color changes due to blood vessel effects.
• Patients should keep track of dosage and side effects experienced.

Don’t take sildenafil with nitrates or nitric oxide donors because your systemic blood pressure could drop to unsafe levels.

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People with sickle cell disease: People with PH related to sickle cell disease can develop a serious condition known as vaso-occlusive crisis. Sildenafil’s effectiveness for PH related to sickle cell anemia hasn’t been established. People with HIV/AIDS: If you have human immunodeficiency virus (HIV/AIDS), consult you pharmacist. Phosphodiesterase inhibitors such as sildenafil can significantly impede the efficacy of some antiretroviral medications. Other conditions: People with dehydration, left-heart diseases and certain abnormalities of the body’s nervous system function should use sildenafil with caution. Use caution when drinking alcoholic beverages or taking anti-hypertension or blood pressure-lowering medications. Sildenafil is broken down predominantly by an enzyme called CYP3A in the liver.

Significant interactions can occur with medications that affect this enzyme pathway.

Sildenafil for ED

Low blood pressure: Blood pressure throughout the body can decrease because sildenafil relaxes arteries throughout the body. People with low blood pressure (less than 90/50 mmHg) should use sildenafil with caution. Prolonged erection: Prolonged erection (greater than four hours) is rare but serious. If you experience prolonged erection, go to an emergency room or contact your doctor immediately. Vision loss: Sudden loss of vision in one or both eyes has occurred in people taking phosphodiesterase 5 inhibitors, including sildenafil.

Distribution of Dispensed Dosage Forms (2023)

Sudden vision loss can indicate serious dysfunction of the optic nerve and needs immediate medical attention. This type of blindness, called non-arteritic anterior ischemic optic neuropathy, can be permanent. It isn’t clear whether the blindness is related to the drug or underlying cardiovascular diseases that increase the risk for this type of blindness, even without sildenafil use. No research exists to determine whether sildenafil is beneficial or safe for people with retinitis pigmentosa. Sildenafil isn’t recommended for people with that condition.

Cessation and Adverse Effects of Treatment

Seek immediate medical attention if you suddenly lose your vision. Hearing loss: If you have sudden hearing loss accompanied by dizziness and/or ear ringing occurs, seek prompt medical attention. Allergic reaction: sildenafil premature ejaculation Although allergies to sildenafil are possible, they aren’t likely. Any medication can cause side effects or sensitivities. Check with your doctor if you develop a rash or throat tightening. Simultaneous use of bosentan and sildenafil can increase bosentan in blood and decrease sildenafil levels.

• Sildenafil is a popular choice for men seeking non-invasive ED therapy.
• It's important to have realistic expectations about sildenafil's effects.
• The medication does not increase libido but improves blood flow.
• Patients should limit alcohol consumption when using sildenafil.
• It is recommended to consult a doctor if ED persists despite medication.
• Sildenafil can be used as part of a comprehensive ED treatment plan.
• The medication should be taken approximately an hour before planned activity.
• Some patients experience no side effects at prescribed doses.
• Always confirm that sildenafil is stored properly to maintain efficacy.
• Report any unusual symptoms, such as chest pain or vision loss, immediately.

It’s not known whether those changes are clinically significant.

Viagra Versus Other ED Medications

No regular bloodwork for side effects is required. Your doctor might ask you to monitor your blood pressure regularly, particularly during your first few days taking the drug or when your dose increases. Blood pressure monitoring isn’t necessary for most patients. Note: If you experience any symptoms/side effects mentioned above, promptly notify your physician. Certain patient populations must take precautions while taking sildenafil, while others should avoid it.

Vitamin K Antagonists

Learn about who can and who shouldn’t take this medication: Pregnant and breastfeeding patients: Sildenafil hasn’t caused harm to fetuses in animal studies. However, birth effects haven’t been studied in pregnant or nursing women. There are no adequate and well-controlled human studies. In clinical practice, sildenafil is commonly used for pregnant and lactating women with severe PAH, as the risk of untreated or undertreated PAH is higher than the risk of adverse effects from sildenafil. Children and teens: Clinical trials of sildenafil for pediatric PAH patients have been small and part of studies with a wide range of ages and diseases. Using sildenafil with epoprostenol can reduce sildenafil levels in the blood. Using sildenafil with beta blockers (a heart or blood pressure medicine) can increase sildenafil levels.

• Sildenafil may improve confidence and sexual satisfaction in men with ED.
• The medication is also being researched for pulmonary hypertension treatment.
• Common side effects include dizziness, upset stomach, and vision changes.
• Rare side effects can include priapism, a painful prolonged erection.
• Alcohol can interfere with sildenafil's effectiveness and increase side effects.
• Patients should disclose any heart conditions before using sildenafil.
• Sildenafil may interact with other medications such as alpha-blockers.
• It is not suitable for individuals with severe liver or kidney problems.
• Taking large doses does not necessarily improve efficacy and increases risk.
• Always follow the prescribed dosage and discontinue if adverse effects occur.

We evaluated the efficacy and safety of sildenafil, administered as needed in two sequential double-blind studies of men with erectile dysfunction of organic, psychogenic, or mixed causes.

• Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor.
• The drug was first approved by the FDA in 1998.
• It can be purchased online but requires a prescription in most countries.
• Generic versions of sildenafil are typically cheaper than brand-name Viagra.
• Proper storage involves keeping it at room temperature away from moisture.
• Sildenafil does not protect against sexually transmitted diseases.
• Lifestyle changes like exercise and healthy eating can enhance results.
• Combining sildenafil with other ED treatments should be discussed with a doctor.
• It's important to inform your doctor about all medications you take.
• Sildenafil is not an aphrodisiac and requires sexual stimulation to work.

In a 24-week dose–response study, 532 men were treated with oral sildenafil (25, 50, or 100 mg) or placebo. In a 12-week, flexible dose-escalation study, 329 different men were treated with sildenafil or placebo, with dose escalation to 100 mg based on efficacy and tolerance.

After this dose-escalation study, 225 of the 329 men entered a 32-week, open-label extension study. We assessed efficacy according to the International Index of Erectile Function, a patient log, and a global-efficacy question.

Other targets: Therapeutic roles

Studies haven’t shown any effect on sexual function in women who have taken sildenafil. Phosphodiesterase, an enzyme produced in the lungs and other parts of the body, breaks down a substance called cyclic guanosine monophosphate. Cyclic guanosine monophosphate relaxes and widens arteries. Sildenafil decreases the enzyme’s activity so more cGMP is available to relax or widen the arteries. When the arteries are widened, it’s easier for the heart to pump blood through the lungs, reducing blood pressure in the lungs.

Are there reviews from people who had side effects with 50-mg or 100-mg sildenafil tablets?

As the heart’s ability to pump blood through the lungs increases, it improves a person’s ability to exercise. Revatio is a round, white 20 mg pill, which distinguishes it from Viagra, a blue diamond-shaped pill. The recommended, FDA-approved dose for Revatio is 20 mg three times a day. Patients have received up to 80 mg three times a day in trials and clinical practice. Take each dose four to six hours apart, with or without food.

Other Interactions

The injected form of Revatio generally is available only in hospitals. It’s administered three times a day, through single-use 10 mg (125 mL) doses. Doctors must prescribe sildenafil, and you likely will need approval from your insurance company before starting therapy. Depending on your insurance plan, you might fill your prescription at a retail pharmacy or through specialty pharmacies such as Accredo, Aetna, Alliance Rx Walgreens Prime, Axium, BriovaRx, Cigna, CVS specialty, Humana and Kaiser Permanente. Other side effects include fluid retention, nausea and diarrhea, arm or leg pain, temporary muscle aches, fever and numbness. In the dose–response study, increasing doses of sildenafil were associated with improved erectile function (P values for increases in scores for questions about achieving and maintaining erections were <0.001).

For the men receiving 100 mg of sildenafil, the mean score for the question about achieving erections was 100 percent higher after treatment than at base line (4.0 vs. 2.0 of a possible score of 5).

Proper Use

Several observations support the concept that sildenafil has positive inotropic properties. In patients given inhaled nitric oxide with comparable reductions in the pulmonary vascular resistance, an increase in cardiac output was not noted in comparison to sildenafil.104 Moreover, Nagendran and associates105 confirmed a lack of phosphodiesterase type 5 in normal human right ventricular myocardium but were able to demonstrate its presence in hypertrophied right ventricular myocardium. In addition, they were able to show a positive inotropic effect with phosphodiesterase type 5 inhibition in this tissue. The mechanism of positive inotropy remains to be elucidated. Moreover, novel exciting data suggest that cGMP-dependent protein kinases are involved in the reversal of myocardial hypertrophy and subsequent improvement in ventricular function; thus, phosphodiesterase type 5 inhibitors may have a role in the treatment of ventricular hypertrophy and reverse remodeling.

Pulmonary Arterial Hypertension

In an animal model of ventricular hypertrophy induced by pressure overload, sildenafil administration prevented the development of ventricular hypertrophy and, in animals with established hypertrophy, reversed the hypertrophy. The postulated mechanisms are improved calcium handling, sildenafil-induced increase in cGMP concentration, and thus increase in cGMP-dependent protein kinase activity, which in turn appears to lead to a decrease in downstream hypertrophy signaling. At the same time, animals treated with sildenafil showed an improvement in ventricular systolic function.96,106 These findings are very encouraging and suggest that sil-denafil may successfully and safely decrease pulmonary artery pressures in patients with systolic heart failure and improve symptoms and exercise capacity even in patients with heart failure but without significant pulmonary hypertension.103 Larger prospective clinical trials are needed to confirm these findings and to evaluate the benefit of this agent on morbidity and mortality outcomes in patients with systolic heart failure. Moreover, the evidence that sildenafil may reverse hypertrophy suggests that it may have a role in the treatment of diastolic heart failure, as reviewed in detail in Chapter 48. Sildenafil is used to treat pulmonary arterial hypertension, also known as Group 1 pulmonary hypertension.

Who Should NOT Take Sildenafil

The treatment aims to improve patients’ ability to exercise and delay disease progression. The Food and Drug Administration approved Revatio in 2005 to treat PAH in adults. While Viagra is an FDA-approved form of sildenafil, it’s not used to treat PAH. The FDA approved sildenafil for 1- to 17-year-old patients in 2023. No differences in side effects have been reported among genders. In the last four weeks of treatment in the dose-escalation study, 69 percent of all attempts at sexual intercourse were successful for the men receiving sildenafil, as compared with 22 percent for those receiving placebo (P<0.001).

Does Dual Combination Therapy Work?

Generally, sildenafil seems safe and effective for pediatric patients. The treatment algorithm from the sixth World Symposium on Pulmonary Hypertension recommended PDE5 inhibitors for pediatric patients. People with liver disease: People with mild to moderate liver disease don’t need to adjust their sildenafil doses. Severe liver disease hasn’t been studied. People with kidney disease: People with kidney disease don’t have to adjust their dosage.