Generic Medicine Info
Indications and Dosage
Pulmonary arterial hypertension
Adult: 2.5 mg or 10 mg tid.

Erectile dysfunction
Adult: 50 mg approx 1 hr before sexual intercourse, may adjust depending on response. Max: 100 mg daily.

Pulmonary arterial hypertension
Adult: 5 mg or 20 mg tid.
Child: 1-17 yr ≤20 kg: 10 mg tid; >20 kg: 20 mg tid.
Special Patient Group
Patients on CYP3A4 inhibitors: Initially, not more than 25 mg daily.
Patients on ritonavir-boosted HIV inhibitors: Should not exceed 25 mg 48 hrly.
Patients stable on alpha-blockers: Initially, 25 mg.
Renal Impairment
Erectile dysfunction:
CrCl (mL/min) Dosage
<30 Initially, 25 mg.

Pulmonary arterial hypertension:
CrCl (mL/min) Dosage
<30 20 mg bid.

Pulmonary arterial hypertension:
CrCl (mL/min) Dosage
<30 10 mg bid.
Hepatic Impairment
Erectile dysfunction: Mild or moderate: Initially, 25 mg. Severe: Contraindicated.
Pulmonary arterial hypertension: Mild or moderate: 20 mg bid. Severe: Contraindicated.

Pulmonary arterial hypertension: Mild or moderate: 10 mg bid. Severe: Contraindicated.
May be taken with or without food.
Oral susp: Add a total of 90 mL of water in 2 portions, 60 mL for the 1st addition and 30 mL for the 2nd addition, to provide a susp containing 10 mg/mL. After each addition, cap and shake the bottle vigorously for at least 30 sec.
Patient w/ severe CV disorders (e.g. unstable angina, cardiac failure), loss of vision in 1 eye because of non-arteritic anterior ischaemic optic neuropathy (NAION), hypotension (BP <90/50 mmHg), recent history of stroke or MI, known hereditary degenerative retinal disorders. Severe hepatic impairment. Concomitant use w/ nitrates of any form and nicorandil.
Special Precautions
Patient w/ anatomical deformation of the penis or haematological disorders that may predispose to priapism. Not indicated for pulmonary HTN secondary to sickle-cell disease. Mild to moderate hepatic and severe renal impairment. Childn (chronic use). Pregnancy and lactation.
Adverse Reactions
Headache, flushing, dyspepsia, visual disturbances (e.g. blurred vision, photophobia, chromatopsia, cyanopsia, eye irritation, eye pain and redness); dizziness, insomnia, anxiety, vertigo, epistaxis, nasal congestion, pyrexia, GI disturbances (e.g. diarrhoea, vomiting), priapism; skin rashes, erythema, alopecia, limb/back pain, myalgia, facial oedema, fluid retention, paraesthesia, UTI, dyspnoea, cough, rhinitis, sinusitis, bronchitis, cellulitis, sudden decrease or loss of hearing, anaemia, leucopenia, gynaecomastia, urinary frequency or incontinence, haematuria, seizures, cerebrovascular haemorrhage, transient ischaemic attack, palpitations, syncope, HTN, hypotension. Rarely, hypersensitivity reactions, NAION causing permanent loss of vision, retinal haemorrhage.
Potentially Fatal: Serious CV events (e.g. MI, arrhythmias, tachycardia, unstable angina). 
Patient Counseling Information
This drug may cause dizziness and altered vision, if affected, do not drive or operate machinery. Seek medical assistance in cases of prolonged erection (>4 hr) or sudden visual or hearing loss.
Monitoring Parameters
Monitor BP and pulse when used concurrently w/ hypotensive drugs in the treatment of pulmonary arterial HTN.
Symptoms: Hypotension, syncope, prolonged erection. Management: Supportive treatment. For severe hypotension, may consider placing the patient in the Trendelenburg position, initiating fluid resuscitation, providing judicious use of an IV α-adrenergic agonist (e.g. phenylephrine), providing a combined α- and β-adrenergic agonist (norepinephrine) for BP support, and/or providing intra-aortic balloon.
Drug Interactions
Symptomatic HTN may occur when used w/ alpha-blockers. Reduced clearance w/ CYP3A4 inhibitors (e.g. cimetidine, delavirdine, erythromycin, itraconazole, ketoconazole). Increased plasma concentrations w/ HIV-protease inhibitors particularly by ritonavir-boosted regimens. Decreased plasma concentrations w/ CYP3A4 inducers (e.g. rifampicin, bosentan).
Potentially Fatal: Potentiation of hypotensive effects of nitrates of any form and nicorandil.
Food Interaction
May increase plasma levels w/ grapefruit juice.
Mechanism of Action: Sildenafil inhibits phosphodiesterase type-5 (PDE-5) which is responsible for cyclic guanosine monophosphate (cGMP) degradation in the corpus cavernosum. Inhibition of PDE-5 increases cGMP which results in pulmonary vascular smooth muscle cells relaxation.
Onset: Approx 60 min.
Duration: 2-4 hr.
Absorption: Rapidly absorbed from the GI tract. Bioavailability: Approx 40%. Time to peak plasma concentration: W/in 30-120 min.
Distribution: Widely distributed into body tissues. Plasma protein binding: Approx 96%.
Metabolism: Hepatically by CYP3A4 (major route) and CYP2C9 isoenzymes.
Excretion: Mainly via faeces (as metabolites); urine (lesser extent). Terminal half-life: Approx 4 hr.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Sildenafil, CID=135398744, (accessed on Jan. 23, 2020)

Store between 15-30°C.
MIMS Class
Drugs for Erectile Dysfunction & Ejaculatory Disorders / Other Cardiovascular Drugs
ATC Classification
G04BE03 - sildenafil ; Belongs to the class of drugs used in erectile dysfunction.
Anon. Sildenafil. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. Accessed 07/11/2014.

Buckingham R (ed). Sildenafil Citrate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. Accessed 07/11/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Sildenafil Citrate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). Accessed 07/11/2014.

Revatio Tablet, Film Coated; Injection, Solution; Powder, for Suspension (Pfizer Laboratories Div Pfizer Inc). DailyMed. Source: U.S. National Library of Medicine. Accessed 10/01/2014.

Disclaimer: This information is independently developed by MIMS based on Sildenafil from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by
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