Description

Simple

A medication used to treat the inability to get or keep an erection.

Clinical

A phosphodiesterase inhibitor used for the treatment of erectile dysfunction.

Overview

In eliciting its mechanism of action, sildenafil ultimately prevents or minimizes the breakdown of cyclic guanosine monophosphate (cGMP) by inhibiting cGMP specific phosphodiesterase type 5 (PDE5) [11, 12, 13, 14, 15, 16, 8, 9]. The result of doing so allows cGMP present in both the penis and pulmonary vasculature to elicit smooth muscle relaxation and vasodilation that subsequently facilitates relief in pulmonary arterial hypertension and the increased flow of blood into the spongy erectile tissue of the penis that consequent... Read more

Pharmacology

Indication

Sildenafil is a phosphodiesterase-5 (PDE5) inhibitor that is predominantly employed for two primary indications:

(1) the treatment of erectile dysfunction [ Read more

Pharmacodynamic

In vitro studies have shown that sildenafil is selective for phosphodiesterase-5 (PDE5) [11, 12, Read more

Mechanism of action

Sildenafil is an oral therapy for erectile dysfunction [ Read more

Absorption

Sildenafil is known to be quickly absorbed, with maximum plasma concentrations being observed within 30-120 minutes (with a median of 60 minutes) of oral administration in a fasting patient [11, Read more

Protein binding

It is generally observed that sildenafil and its main circulating N-desmethyl metabolite are both estimated to be about 96% bound to plasma proteins [11, Read more

Volume of distribution

The mean steady-state volume of distribution documented for sildenafil is approximately 105 L - a value which suggests the medication undergoes distribution into the tissues [11, Read more

Clearance

The total body clearance documented for sildenafil is 41 L/h [11, 12, Read more

Half life

The terminal phase half-life observed for sildenafil is approximately 3 to 5 hours [11, 12, Read more

Route of elimination

After either oral or intravenous administration, sildenafil is excreted as metabolites predominantly in the feces (approximately 80% of the administered oral dose) and to a lesser extent in the urine (approximately 13% of the administered oral dose) [ Read more

Toxicity

In single-dose volunteer studies of doses up to 800 mg, adverse reactions were similar to those seen at lower doses, but the incidence rates and severities were increased [11, Read more

Adverse Effects

Contraindications

  • Sex Group: all
  • Regions: US
  • Patient Conditions:
      • Name: Blood pressure < 90/50 mmHg at therapy initiation Severe hypotension
      • Drugbank Id: DBCOND0118168
      • Combination Of:
        • Additional Characteristics:
          • blood pressure < 90/50 mmHg at therapy initiation
        • Included Conditions:
            • Name: Severe hypotension
            • Drugbank Id: DBCOND0118169
  • Sex Group: all
  • Regions: US
  • Patient Conditions:
      • Name: Recent Myocardial Infarction
      • Drugbank Id: DBCOND0043731
      • Name: Recent Stroke
      • Drugbank Id: DBCOND0049526
  • Sex Group: all
  • Regions: US
  • Patient Conditions:
      • Name: Severe Hepatic Impairment
      • Drugbank Id: DBCOND0070791
      • Modification Of:
        • Base:
          • Name: Heptic Impairment
          • Drugbank Id: DBCOND0072269
        • Severity:
          • Includes:
            • severe
  • Sex Group: male
  • Regions: US
  • Above Age:
    • Amount: 18
    • Unit: year
  • Patient Conditions:
      • Name: Men for whom sexual activity is inadvisable
      • Drugbank Id: DBCOND0107999
  • Sex Group: all
  • Regions: US
  • Patient Conditions:
      • Name: Non-Arteritic Anterior Ischemic Optic Neuropathy
      • Drugbank Id: DBCOND0031403
  • Sex Group: all
  • Regions: US
  • With Categories:
      • Name: Cytochrome P-450 CYP3A4 Inhibitors (strong)
      • Drugbank Id: DBCAT002647
  • Sex Group: all
  • Regions: US
  • With Categories:
      • Name: Guanylate Cyclase Stimulators
      • Drugbank Id: DBCAT004472
  • Sex Group: all
  • Regions: US
  • With Categories:
      • Name: Nitric Oxide Donors
      • Drugbank Id: DBCAT000756
      • Mesh Id: D020030

Food Interactions

    Information currently not available.

Interactions

Type in a drug name to check for interaction with Sildenafil
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The risk or severity of hemorrhage can be increased when (R)-warfarin is combined with Sildenafil.
(S)-Warfarin
The risk or severity of hemorrhage can be increased when (S)-Warfarin is combined with Sildenafil.
1-(2-Phenylethyl)-4-phenyl-4-acetoxypiperidine
The metabolism of Sildenafil can be decreased when combined with 1-(2-Phenylethyl)-4-phenyl-4-acetoxypiperidine.
2,4-thiazolidinedione
The therapeutic efficacy of 2,4-thiazolidinedione can be increased when used in combination with Sildenafil.
4-hydroxycoumarin
The risk or severity of hemorrhage can be increased when 4-hydroxycoumarin is combined with Sildenafil.
4-Methoxyamphetamine
The metabolism of 4-Methoxyamphetamine can be decreased when combined with Sildenafil.
5-methoxy-N,N-dimethyltryptamine
The metabolism of 5-methoxy-N,N-dimethyltryptamine can be decreased when combined with Sildenafil.
6-Deoxyerythronolide B
The metabolism of Sildenafil can be decreased when combined with 6-Deoxyerythronolide B.
7-ethyl-10-hydroxycamptothecin
The metabolism of Sildenafil can be decreased when combined with 7-ethyl-10-hydroxycamptothecin.
9-aminocamptothecin
The metabolism of Sildenafil can be decreased when combined with 9-aminocamptothecin.
Abafungin
The serum concentration of Sildenafil can be increased when it is combined with Abafungin.
Abatacept
The metabolism of Sildenafil can be increased when combined with Abatacept.
Abciximab
The risk or severity of hemorrhage can be increased when Abciximab is combined with Sildenafil.
Abemaciclib
The serum concentration of Sildenafil can be increased when it is combined with Abemaciclib.
Abiraterone
The metabolism of Sildenafil can be decreased when combined with Abiraterone.
Acalabrutinib
The metabolism of Sildenafil can be decreased when combined with Acalabrutinib.
Acarbose
The therapeutic efficacy of Acarbose can be increased when used in combination with Sildenafil.
Acebutolol
Sildenafil may increase the antihypertensive activities of Acebutolol.
Acenocoumarol
The risk or severity of hemorrhage can be increased when Acenocoumarol is combined with Sildenafil.
Acepromazine
The risk or severity of hypotension, dyspepsia, and headache can be increased when Sildenafil is combined with Acepromazine.
16 References
  1. 1 . Boolell M, Allen MJ, Ballard SA, Gepi-Attee S, Muirhead GJ, Naylor AM, Osterloh IH, Gingell C: Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. Int J Impot Res. 1996 Jun;8(2):47-52.PubMed: 8858389
  2. 2 . Cheitlin MD, Hutter AM Jr, Brindis RG, Ganz P, Kaul S, Russell RO Jr, Zusman RM: ACC/AHA expert consensus document. Use of sildenafil (Viagra) in patients with cardiovascular disease. American College of Cardiology/American Heart Association. J Am Coll Cardiol. 1999 Jan;33(1):273-82.PubMed: 9935041
  3. 3 . Fries R, Shariat K, von Wilmowsky H, Bohm M: Sildenafil in the treatment of Raynaud's phenomenon resistant to vasodilatory therapy. Circulation. 2005 Nov 8;112(19):2980-5.PubMed: 16275885
  4. 4 . Unegbu C, Noje C, Coulson JD, Segal JB, Romer L: Pulmonary Hypertension Therapy and a Systematic Review of Efficacy and Safety of PDE-5 Inhibitors. Pediatrics. 2017 Mar;139(3). pii: peds.2016-1450. doi: 10.1542/peds.2016-1450.PubMed: 28235796
  5. 5 . Gong B, Ma M, Xie W, Yang X, Huang Y, Sun T, Luo Y, Huang J: Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysis. Int Urol Nephrol. 2017 Oct;49(10):1731-1740. doi: 10.1007/s11255-017-1644-5. Epub 2017 Jul 24.PubMed: 28741090
  6. 6 . Nichols DJ, Muirhead GJ, Harness JA: Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality. Br J Clin Pharmacol. 2002;53 Suppl 1:5S-12S.PubMed: 11879254
  7. 7 . Goldstein I, Burnett AL, Rosen RC, Park PW, Stecher VJ: The Serendipitous Story of Sildenafil: An Unexpected Oral Therapy for Erectile Dysfunction. Sex Med Rev. 2019 Jan;7(1):115-128. doi: 10.1016/j.sxmr.2018.06.005. Epub 2018 Oct 6.PubMed: 30301707
  8. 8 . Electronic Medicines Compendium: Sildenafil 25mg, 50mg, 100mg film-coated tablets Monograph Link
  9. 9 . Electronic Medicines Compendium: Revatio (sildenafil citrate) 20 mg film-coated tablets Monograph Link
  10. 10 . Forbes: With Viagra Now Available Over-The-Counter In The U.K., Will The U.S. Follow Suit? Link
  11. 11 . Revatio (sildenafil) FDA Label File
  12. 12 . Viagra (sildenafil citrate) FDA Label File
  13. 13 . Viagra (sildenafil citrate) Tablets 25 mg, 50 mg, and 100 mg Canadian Product Monograph File
  14. 14 . Revatio (sildenafil citrate) Canadian Product Monograph File
  15. 15 . Revatio (sildenafil citrate) EMA Label File
  16. 16 . Viagra (sildenafil citrate) EMA Label File