pharmacopeia
GET
/api/v1/drug/sildenafil
2D structure
5-[2-ethoxy-5-(4-methylpiperazin-1-yl)sulfonylphenyl]-1-methyl-3-propyl-6H-pyrazolo[4,5-d]pyrimidin-7-one
SMILES CCCC1=NN(C2=C1N=C(NC2=O)C3=C(C=CC(=C3)S(=O)(=O)N4CCN(CC4)C)OCC)C
InChIKey BNRNXUUZRGQAQC-UHFFFAOYSA-N

Mechanism of action

Sourced from openFDA

The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.

Phosphodiesterase 5

Indications

Sourced from openFDA
  • Sildenafil tablets are indicated for the treatment of erectile dysfunction.ICD-10: N52.9

Contraindications

Sourced from openFDA
  • Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates ( 4.1 , 7.1 , 12.2 ) Known hypersensitivity to sildenafil or any component of tablet ( 4.2 ) Administration with guanylate cyclase (GC) stimulators, such as riociguat ( 4.3 ) 4.1 Nitrates Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1 , 12.2 ) ], sildenafil tablets was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.contraindicated

Dosage & administration

Sourced from openFDA

For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity ( 2.1 ) Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg ( 2.1 ) Maximum recommended dosing frequency is once per day ( 2.1 ) 2.1 Dosage Information For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity. The maximum recommended dosing frequency is once per day. Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg. 2.2 Use with Food Sildenafil tablets may be taken with or without food. 2.3 Dosage Adjustments in Specific Situations Sildenafil tablets was shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [ see Contraindications (4.1) , Drug Interactions (7.1) , and Clinical Pharmacology (12.2) ]. When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [ see Warnings and Precautions (5.5) , Drug Interactions (7.2) , and Clinical Pharmacology (12.2) ].

Warnings & precautions

Sourced from openFDA

Patients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status ( 5.1 ) Patients should seek emergency treatment if an erection lasts >4 hours. Use sildenafil with caution in patients predisposed to priapism ( 5.2 ) Patients should stop sildenafil tablets and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION). Sildenafil tablets should be used with caution, and only when the anticipated benefits outweigh the risks, in patients with a history of NAION. Patients with a "crowded" optic disc may also be at an increased risk of NAION. ( 5.3 ) Patients should stop sildenafil tablets and seek prompt medical attention in the event of sudden decrease or loss of hearing ( 5.4 ) Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. Concomitant use may lead to hypotension ( 5.5 ) Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. In patients taking strong CYP inhibitors, such as ritonavir, sildenafil exposure is increased. Decrease in sildenafil dosage is recommended ( 2.4 , 5.6 ) 5.1 Cardiovascular There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. Therefore, treatments for erectile dysfunction, including sildenafil, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status.

Adverse reactions

Sourced from openFDA

The following are discussed in more detail in other sections of the labeling: Cardiovascular [ see Warnings and Precautions (5.1) ] Prolonged Erection and Priapism [ see Warnings and Precautions (5.2) ] Effects on the Eye [ see Warnings and Precautions (5.3) ] Hearing Loss [ see Warnings and Precautions (5.4) ] Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives [ see Warnings and Precautions (5.5) ] Adverse Reactions with the Concomitant Use of Ritonavir [ see Warnings and Precautions (5.6) ] Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies [ see Warnings and Precautions (5.7) ] Effects on Bleeding [ see Warnings and Precautions (5.8) ] Counseling Patients About Sexually Transmitted Diseases [ see Warnings and Precautions (5.9) ] The most common adverse reactions reported in clinical trials (≥ 2%) are headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness, and rash. Most common adverse reactions (≥ 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Nivagen Pharmaceuticals, Inc. at 1-877-977-0687 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Use in specific populations

Sourced from openFDA

Geriatric use: Consider a starting dose of 25 mg ( 2.5 , 8.5 ) Severe renal impairment: Consider a starting dose of 25 mg ( 2.5 , 8.6 ) Hepatic impairment: Consider a starting dose of 25 mg ( 2.5 , 8.7 ) 8.1 Pregnancy Risk Summary Sildenafil is not indicated for use in females. There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m 2 basis ( see Data ). Data Animal Data No evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m 2 basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m 2 basis in a 50 kg subject. 8.2 Lactation Risk Summary Sildenafil is not indicated for use in females. Limited data indicate that sildenafil and its active metabolite are present in human milk.

Pharmacokinetics

Sourced from openFDA
Metabolism
Sildenafil is rapidly absorbed after oral administration, with a mean absolute bioavailability of 41% (range 25-63%). The pharmacokinetics of sildenafil are dose-proportional over the recommended dose range.

Overdosage

Sourced from openFDA

In studies with healthy volunteers of single doses up to 800 mg, adverse reactions were similar to those seen at lower doses but incidence rates and severities were increased. In cases of overdose, standard supportive measures should be adopted as required. Renal dialysis is not expected to accelerate clearance as sildenafil is highly bound to plasma proteins and it is not eliminated in the urine.

Approval history

Sourced from openFDA
  • Mar 27, 1998NDANDA020895Viatris
  • Jun 3, 2005NDANDA021845Viatris
  • Nov 18, 2009NDANDA022473Viatris
  • Aug 30, 2012NDANDA203109Viatris
  • Nov 6, 2012ANDAANDA091479Torrent Pharms Ltd
  • Nov 6, 2012ANDAANDA202598Chartwell Rx
  • Feb 28, 2013ANDAANDA202025Amneal Pharms
  • Dec 16, 2025NDANDA210858Ibsa

FAERS reports

View JSON
Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
125,276 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Dyspnoea13,17111%
  2. 2Drug Ineffective12,68910%
  3. 3Headache10,0618.0%
  4. 4Death9,0667.2%
  5. 5Diarrhoea6,9375.5%
  6. 6Nausea6,4055.1%
  7. 7Fatigue6,2865.0%
  8. 8Dizziness5,7544.6%
  9. 9Pneumonia4,9193.9%
  10. 10Cough4,6403.7%
  11. 11Malaise4,4513.6%
  12. 12Off Label Use3,8883.1%
  13. 13Vomiting3,7603.0%
  14. 14Pain3,7403.0%
  15. 15Hypotension3,7333.0%

Literature

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Recent PubMed references pinned to Sildenafil as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

View JSON

The 10 most recently updated of 488 ClinicalTrials.gov registrations naming Sildenafil as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Pharmacogenomics

View JSON

CPIC-curated drug–gene pairs for Sildenafil. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

  • GNB3CPIC D (provisional)ClinPGx 3

Structural analogs

View JSON

Ranked by 2D fingerprint (Tanimoto) similarity over PubChem structures. Structural proximity only — not a claim of therapeutic equivalence.

Frequently asked questions

How does Sildenafil work?
The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.
What is Sildenafil used for?
According to FDA labeling, Sildenafil carries indications including: Sildenafil tablets are indicated for the treatment of erectile dysfunction.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Sildenafil?
Sildenafil is classified as Drugs used in erectile dysfunction, Phosphodiesterase 5 Inhibitor, Phosphodiesterase 5 Inhibitors, Penile Venous Vasodilation, Pulmonary Venous Vasodilation.
What are the brand names for Sildenafil?
Sildenafil is marketed under brand names including Liqrev, Revatio, Viagra, Vybrique.
What are the contraindications for Sildenafil?
Sildenafil labeling lists contraindications including: Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates ( 4.1 , 7.1 , 12.2 ) Known hypersensitivity to sildenafil or any component of tablet ( 4.2 ) Administration with guanylate cyclase (GC) stimulators, such as riociguat ( 4.3 ) 4.1 Nitrates Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1 , 12.2 ) ], sildenafil tablets was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.. Always consult the full prescribing information and a clinician.
Note. Data for sildenafil is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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