Sildenafil Medication Monograph

Written information about this prescription has been provided for you. Please read this information before you take the medication. If you have questions concerning this prescription, a pharmacist is available during normal business hours to answer these questions at 888-689-2271

Información por escrito acerca de esta receta se le a presentado a usted. Favor de leer esta información antes de tomar el medicamento. Si usted tiene preguntas tocante esta receta, un farmacéutico estará presente durante horas de negocio para contestar sus preguntas

Complaints concerning the practice of pharmacy may be filed with the Texas State Board of Pharmacy at:

Quejas sobre la practica de farmacia pueden ser reportadas al Concilio Farmacia del Estado de Tejas:

William P. Hobby Building Ste. 3-600, 333 Guadalupe Street, Box 21

Austin, Texas 78701-3942 Tel: (512) 305-8000

Sildenafil is a phosphodiesterase type 5 (PDE-5) inhibitor that relaxes the smooth muscles in the body including those in the penis, bladder, prostate, and lungs. By relaxing the smooth muscles in the penis, blood is able to flow into the tissue more easily when sexual stimulation occurs

Indications: Sildenafil is used for erectile dysfunction. It is taken as needed for intercourse. It will not produce an erection without sexual stimulation

Dosing (Adults)Erectile dysfunction: Oral: Usual dose: 50 mg once daily 1 hour (range: 30 minutes to 4 hours) before sexual activity as needed; dosing range: 25 to 100 mg once daily; maximum dose: 100 mg once daily

Sildenafil should be taken on an empty stomach, as food can delay its absorption 

Renal Dosing: Crcl >31 ml/min: No dosage adjustment necessary

Crcl <30 ml/min or hemodialysis: Starting dose of 25 mg should be considered 

Hepatic impairment: Mild-to-moderate hepatic impairment: Starting dose of 25 mg should be considered Severe hepatic impairment: Starting dose of 25 mg should be considered

Contraindications: Hypersensitivity to sildenafil or any component of the formulation; concurrent use (regularly/intermittently) of organic nitrates in any form (eg, nitroglycerin, isosorbide dinitrate); concomitant use of riociguat (a guanylate cyclase stimulator)


Color discrimination: May cause dose-related impairment of color discrimination

Hearing loss: Sudden decrease or loss of hearing has been reported; hearing changes may be accompanied by tinnitus and dizziness. A direct relationship between therapy and hearing loss has not been determined

Hypersensitivity: Hypersensitivity reactions, including rash, urticaria, anaphylactic reaction, and anaphylactic shock, have been reported

Hypotension: Decreases in blood pressure may occur due to vasodilator effects; use with caution in patients with left ventricular outflow obstruction, those on antihypertensive therapy, with resting hypotension (BP <90/50 mm Hg), fluid depletion, or autonomic dysfunction; may be more sensitive to hypotensive actions. Patients should be hemodynamically stable prior to initiating therapy at the lowest possible dose. Monitor blood pressure when combining with medications that lower blood pressure. Substantial consumption of alcohol may increase the risk of hypotension. Avoid or limit alcohol consumption

Priapism: Painful erection >6 hours in duration has been reported rarely. Seek medical assistance for erection lasting

>4 hours. Use with caution in patients who have conditions which may predispose them to priapism

Vision loss: Sudden loss of vision in one or both eyes, including permanent loss of vision, may occur and be a sign of nonarteritic anterior ischemic optic neuropathy (NAION). Risk may be increased with a history of vision loss. A direct relationship between therapy and vision loss has not been determined

Drug interactions: Alpha blockers: If stabilized on either alpha blockers or sildenafil therapy, initiate new therapy with the other agent at the lowest possible dose. CYP3A4 inhibitors: Dose reduction of sildenafil to 25 mg per dose is recommended with strong CYP3A4 inhibitors. Some examples include: azole antifungals, clarithromycin, doxycycline, erythromycin, grapefruit juice, imatinib, isoniazid, nefazodone, protease inhibitors, etc. Sildenafil max dose of 25mg/48 hrs with ritonavir, atazanavir, or darunavir

Please speak with your doctor or pharmacist about other possible drug interactions as this list is not all-inclusive

Adverse Reactions: Flushing of the face, runny nose, headache, dizziness upon standing, upset stomach, back pain or muscle pain 

Storage: Room temperature 

Patient Education: 

What should I tell my doctor about before taking this medication?

Bleeding disorders, eye problems, history of or current heart problems, irregular heartbeat, liver problems, kidney problems, history of priapism (an erection lasting longer than 4 hours), other medications you take including those that are over-the-counter

Before taking this medication, your doctor must determine if your heart is healthy enough for sex You cannot take this medication if you take nitrates

When and how do I take this medication?

Dose should be taken at least 60 minutes prior to sexual activity. If there is food in the stomach, this medication can take longer to work and administration should be timed accordingly

Effects of sildenafil can last up to 24 hours

What side effects should I call my doctor about right away?

Chest pain or pressure, a heartbeat that is very fast or does not feel normal, a very bad headache, extreme dizziness or passing out, hearing loss or ringing in ears, an erection lasting longer than 4 hours, changes in eyesight, or blurry vision

What should I do if this medication does not produce the desired effect?

Sildenafil will not produce an erection without sexual stimulation. You must be aroused for sildenafil to work 

Sildenafil takes 30-60 minutes to work but a fatty meal can delay effects. Sildenafil works best on an empty stomach. If you have consumed food before taking sildenafil, you may need to wait longer to see an effect. Even on an empty stomach, some people metabolize sildenafil slower than others. You may need to wait 2-3 hours to see an effect

This medication should be tried at least 3 different times (different days, at least 24 hours apart) before determining that it does not work for