Sildenafil Oral

Describe the clinically important drug interactions of sildenafil.

6. Response and effectiveness

Sildenafil is a medication used in the management and treatment of erectile dysfunction and pulmonary arterial hypertension. It is in the phosphodiesterase-5 inhibitor (PDE5-I) class of medications. This activity describes the indications, actions, adverse effects, and contraindications of sildenafil as an agent in the clinical setting. Knowledge therein is critical for appropriate healthcare team management of patients with erectile dysfunction, pulmonary arterial hypertension, and/or related conditions. Explain the mechanism of action of sildenafil in the treatment of erectile dysfunction and pulmonary arterial hypertension. Outline appropriate monitoring of sildenafil therapy in erectile dysfunction and pulmonary arterial hypertension. Summarize the role of the interprofessional healthcare team in improving care coordination and communication to improve outcomes related to sildenafil therapy.

• Sildenafil citrate is manufactured by several pharmaceutical companies.
• Its chemical formula is C22H30N6O4S.
• It has a half-life of approximately 4 hours in the body.
• The drug enhances nitric oxide activity in the corpus cavernosum.
• It’s important to follow prescribed dosing to avoid adverse effects.
• It is classified as a phosphodiesterase type 5 inhibitor.
• Sildenafil was initially researched for angina before ED use.

Sildenafil was the first phosphodiesterase-5 (PDE5) inhibitor approved for use, receiving US Food and Drug Administration approval for use in sildenafil pick up erectile dysfunction (ED) on March 27, 1998.

• Sildenafil citrate was first approved by the FDA in 1998.
• Its brand name is Viagra, but generic versions are available.
• The drug is available in tablets of various strengths, typically 25-100 mg.
• It can be prescribed for both men and in specific cases, women.
• Proper dosage varies based on health status and response.
• Use caution in patients with heart problems or low blood pressure.
• It is not a hormone or a testosterone booster.

[1] It also has US Food and Drug Administration (FDA) approval for the treatment of World Health Organization (WHO) Group I pulmonary hypertension (also known as pulmonary arterial hypertension [PAH]) in adults to improve exercise tolerance and delay clinical worsening. [2] Sildenafil-induced delay in clinical worsening is demonstrated when sildenafil was used concomitantly with epoprostenol therapy. Clinical trials have established effectiveness for short-term use (12-16 weeks) and included patients, mainly patients with New York Heart Association (NYHA) Functional Class II-III symptoms and having idiopathic etiology or connective tissue disease (CTD). However, the addition of sildenafil to bosentan therapy did not result in any improvement in exercise capacity. Sildenafil is also occasionally used off-label for the treatment of: The molecular structure of sildenafil mimics that of cyclic guanosine monophosphate (cGMP). This similarity protects cGMP from degradation because sildenafil can bind to the catalytic site to act as a competitive inhibitor of cGMP-specific PDE5. This enzyme normally catalyzes the breakdown of vasodilatory cGMP. When PDE5 is active, cGMP is degraded, causing the vascular smooth muscle contraction, thereby limiting blood flow.

[7] When PDE5 becomes inhibited, the accumulation of cGMP leads to increased cGMP-dependent protein kinase activity, which phosphorylates multiple targets in the smooth muscle cell. The result of smooth muscle cell target protein phosphorylation is a decrease in intracellular calcium, increased efflux of potassium, and deactivation of myosin light chain kinase, ultimately causing smooth muscle relaxation. Relaxation of vascular smooth muscle in the corpus cavernosum leads to penile erection when the cavernosal sinusoids engorge with blood to compress the subtunical veins against the tunica albuginea.

What is Sildenafil Citrate?

If you notice a sudden decrease or loss of hearing, talk to your doctor right away. It is not possible to determine whether these events are related directly to this class of oral medicines, including sildenafil citrate, or to other diseases or medicines, to other factors, or to a combination of factors. Heart attack, stroke, irregular heartbeats, and death. Most of these happened in men who already had heart problems. Tell your doctor right away if you have an erection that lasts more than 4 hours.

Missed Dose

Nosebleed, headache, upset stomach, getting red or hot in the face (flushing), trouble sleeping, as well as fever, erection increased, respiratory infection, nausea, vomiting, bronchitis, pharyngitis, runny nose, and pneumonia in children. Tell your doctor if you have any side effect that bothers you or doesn’t go away. These are not all the possible side effects of sildenafil citrate. For more information, ask your doctor or pharmacist. Store sildenafil tablets at controlled room temperature, between 68°F to 77°F (20°C to 25°C). In patients with vasoactive pulmonary arterial hypertension, vasodilation of the pulmonary artery leads to reduced resistance to blood flow, with subsequent reductions in mean pulmonary arterial pressure. Sildenafil is available as oral tablets of 25 mg, 50 mg, and 100 mg strength for ED. Most patients receive a prescription for 50 mg of oral sildenafil, taken as needed approximately 1 hour before sexual activity. [7] The dose can be titrated upward to a maximum of 100 mg or down to 25 mg based on individual effectiveness and tolerance.

IV Compatibility

Food and Drug Administration Ltd. Ahmedabad, INDIA 382220 For BluePoint Laboratories Rev. Alcohol-Sildenafil interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication. The contents of this FDA label are provided by the National Library of Medicine.

Viagra and other medications

"Effects of sildenafil on esophageal motility of patients with idiopathic achalasia". "Sildenafil citrate for SSRI-induced sexual side effects". "Sildenafil in the treatment of antipsychotic-induced erectile dysfunction: a randomized, double-blind, placebo-controlled, flexible-dose, two-way crossover trial". "Sildenafil (viagra) facilitates weaning of inhaled nitric oxide following placement of a biventricular-assist device". "Safety and efficacy of sildenafil citrate for the treatment of female sexual arousal disorder: a double-blind, placebo controlled study". Patients are advised not to exceed a maximum dosing frequency of once daily. It can be taken 30 minutes to 4 hours before desired intercourse. The onset of action can occur within 30 minutes, while the duration of the effect can last up to 18 hours. Consider starting at a dose of 25 mg in patients with hepatic dysfunction (eg, cirrhosis), patients with creatinine clearance (CLcr) less than 30 mL/minute (severe renal impairment), and patients age 65 years and above, as the administration of sildenafil in these group patients have resulted tablet sildenafil 50 mg in higher plasma levels of sildenafil. Patients taking concomitant inhibitors of CYP3A4 may benefit from initiation at the lower dosage. In the treatment of PAH, sildenafil is available in 20 mg tablets, oral suspension 10 mg/mL, and injectable 10 mg/12.5 mL forms. The recommended dosage for tablet and oral suspension formularies is 5 mg or 20 mg three times daily, 4 to 6 hours apart. Injections are dosed at 2.5 mg or 10 mg three times a day, 4 to 6 hours apart, as an intravenous bolus. [11][12] Sildenafil injection is only indicated for the continued treatment of PAH when patients are currently on prescribed oral sildenafil treatment and are temporarily unable to take medicine orally.

Warnings & Precautions

"Efficacy and safety of sildenafil citrate in women with sexual dysfunction associated with female sexual arousal disorder". "Vaginal sildenafil (Viagra): a preliminary report of a novel method to improve uterine artery blood flow and endometrial development in patients undergoing IVF". "Comparison of efficacy of sildenafil-only, sildenafil plus topical EMLA cream, and topical EMLA-cream-only in treatment of premature ejaculation". "Assessment of as needed use of pharmacotherapy and the pause-squeeze technique in premature ejaculation". "Efficacy of sildenafil citrate (Viagra) in men with premature ejaculation".

Dosage Modifications

"Sildenafil ameliorates effects of inhaled nitric oxide withdrawal". This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal. A service of the National Library of Medicine, National Institutes of Health. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. No dose adjustment is required in patients with renal impairment (including severe impairment CLcr <30 mL/min). No dose adjustment is required for mild to moderate hepatic impairment.

Its use is not studied in patients with severe hepatic impairment. Pediatric Patients: Increased mortality with increasing sildenafil dose was observed in a clinical trial of pediatric patients with PAH. Deaths were first reported after approximately 1 year of use, and hence, sildenafil, particularly chronic use, is not recommended in pediatric patients with PAH.

Pregnant Women: There are increased risks for stroke, heart failure, preterm delivery, and maternal and fetal death for pregnant women with untreated pulmonary arterial hypertension.

Small case studies in pregnant women with PAH indicate a low risk of harm, though caution is warranted.

7. Interactions

Keep sildenafil citrate and all medicines away from children. Medicines are sometimes prescribed for purposes that are not in the patient leaflet. Do not use sildenafil citrate for a condition for which it was not prescribed. Do not give sildenafil citrate to other people, even if they have the same symptoms you have. This patient leaflet summarizes the most important information about sildenafil citrate.

Does Viagra treat ED that’s related to diabetes?

If you would like more information about sildenafil citrate, talk with your doctor. You can ask your doctor or pharmacist for information about sildenafil citrate that is written for health professionals. For more information go to or call 1-877-835-5472. This product’s label may have been updated. For current full prescribing information, please visit This Patient Information has been approved by the U.S. Breastfeeding Women: There is a lack of information about the effects of sildenafil on milk production and the effects of sildenafil on breastfed infants. Sildenafil has systemic vasodilatory effects and, as such, should be prescribed with caution to patients who may be sensitive to such blood pressure changes, such as patients with left ventricular outflow obstruction and impaired autonomic control of blood pressure.