Sildenafil is a Medicine belongs to Urological drugs group whose information about Brand can be referenced from   Book : Martindale    Page : 2367   Edition : 38  

  ►   Brandname : Caverta; Nipatra; Admas Delite, Juan, Penegra, Silagra, Viagra
  ►  Strength : Tablet with 20 mg.  Tablet with 25 mg.  Tablet with 50 mg.  Tablet with 100 mg.  Oral Suspension with .  Injection with

Reference of this Medicine for its Strength can be taken from   Book : Basic & Clinical pharmacology    Page : 209   Edition : 12   Martindale    Page : 2367   Edition : 38   Martindale    Page : 2364   Edition : 38  
A Route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.

  ►  Route of administration : Oral, IV
Reference :-   Book : Martindale    Page : 2398   Edition : 37   Martindale    Page : 2364   Edition : 38  

Dosing of Medicine differ in Adult & Pediatrics ↓

Adult Dose

S.No Ailment   Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency   Additional Info
1 Erectile dysfunction Oral 50 mg Tablet one hour before sexual intercourse.
2 Erectile dysfunction Oral 25 mg Tablet For patients over 65 years of age; An initial dose of no more than 25 mg daily is advised in patients taking sildenafil with inhibitors of cytochrome P450 isoenzyme CYP3A4; the dose should not exceed 25 mg every 48 hours if given with ritonavir-boosted HIV-protease inhibitors.
3 Pulmonary arterial hypertension Oral 20 mg Tablet t.i.d.

Ref :-  Book : Martindale    Page : 2364   Edition : 38  



Pediatric Dose

S.No Ailment   Age Min   Age Max   Weight ( Kg ) Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency  Additional Info  
1 Pulmonary arterial hypertension up to 18 Year Oral 250 500 micrograms/kg Tablet
2 Pulmonary arterial hypertension 20 kg or less Oral 10 mg Tablet t.i.d.
3 Pulmonary arterial hypertension 6 Year or older over 20 kg Oral 20 mg Tablet t.i.d.

Ref :- Book : Martindale    Page : 2364   Edition : 38  
►  Side Effect : Headache, Flushing, Dyspepsia, Blurred Vision, Photophobia, Chromatopsia, Cyanopsia, Eyes irritation, Pain, Redness, Dizziness, Insomnia, Anxiety, Vertigo, Epistaxis, Nasal congestion, Pyrexia, Gastrointestinal disturbance, Diarrhoea, Vomiting, Priapism, Skin rashes, Erythema, Alopecia, Limb back pain, Myalgia, Facial edema, Fluid retention, , Paresthesia, Urinary-tract infections, Dyspnoea, Cough, Rhinitis, Sinusitis, Bronchitis, Cellulitis, Transient ischaemic attacks, Cerebrovascular haemorrhage, palpitations, Syncope, Hypertension, Hypotension, Serious cardiovascular events including myocardial infarction, arrhythmias, tachycardia, unstable angina, and sudden cardiac death.
Ref :-   Book : Martindale    Page : 2365   Edition : 38.  

►  Drug Interaction : Drug interaction of Sildenafil is with , Alpha blocker, Hiv Protease Inhibitors, ,  Nicorandil , Cimetidine , Delavirdine, Erythromycin , Itraconazole , Ketoconazole , Rifampicin , Bosentan
Ref :-   Book : Martindale    Page : 2366   Edition : 38.  


  ►    Mechanism of Drug Drug Interaction :  Sildenafil or other phosphodiesterase type-5 inhibitors may potentiate the hypotensive effects of organic nitrates, and are therefore contra-indicated in patients receiving such drugs. Sildenafil may also enhance the hypotensive effect of nicorandil and use of the two drugs together should be avoided. Symptomatic hypotension may also occur when phosphodiesterase type- 5 inhibitors are given with alpha blockers. Generally, the patient should be stabilised on alpha blocker therapy before the phosphodiesterase type-5 inhibitor is started at a low dose and adjusted according to response. Drugs that inhibit the cytochrome P450 isoenzyme CYP3A4, such as cimetidine, delavirdine, erythromycin, itraconazole, and ketoconazole, may reduce the clearance of phosphodiesterase type-5 inhibitors, necessitating a reduction in dosage. Plasma concentrations of phosphodiesterase type-5 inhibitors are significantly increased by HIV-protease inhibitors, and particularly so by ritonavir-boosted regimens. Such combinations should not be given unless absolutely essential. Grapefruit juice should be avoided with sildenafil or other phosphodiesterase type-5 inhibitors as it may increase their plasma concentrations. Inducers of CYP3A4, such as rifampicin, are likely to decrease plasma concentrations of phosphodiesterase type-5 inhibitors. Bosentan also reduces exposure to sildenafil.
Ref :-   Book : Martindale    Page : 2366   Edition : 38.  


►  Contraindication : Should not be given to those with loss of vision in one eye caused by non-arteritic anterior ischaemic optic neuropathy (NAION), Caution is required in patients with hepatic or severe renal impairment, Patients who experience dizziness or visual disturbances should not drive or operate hazardous machinery.
Ref :-   Book : Martindale    Page : 2366   Edition : 38.  
  ►  Mechanism of Action :   Inhibit PDE5 an enzyme that converts cGMP TO GMP , Leading to cGMP accumulation in target tissues
Ref :-   Book : Principle of Pharmacology (The Pathophysiologic Basis of Drug Therapy)    Page : 369   Edition : 3.  

Pathway of DIETARY Product


​   ► Act.Comp / Nutrient / Food / Herb as follows :- Stephania tetrandra with Another pathway.   Pomegranate juice with same pathway.  

  ►  Pathway with its reference as follows :-
  • Tetrandrine have Cardio-protective activities --- (PDR for Herbal medicines. (2000) (4th ed.). U.S. )
  • PDE 5 ( phoshodiesterase type 5 ) inhibitor --- (rajfer, J. (2008). Pomegranate Juice: Is It the New, All-Natural Phosphodiesterase Type 5 Inhibitor?. Rev Uro, 10(2), 168–169. )

  •   ►  URL --
  • http://www.travolekar.ru/arch/Pdr_for_Herbal_Medicines.pdf .
  • http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2483323/ .

  • DIETARY Substance Interactions


    ​   ► This Medicine interact with :- NA



    ContraIndication DIETARY Substance


    ​   ► This Medicine contraindicate with :- EPIMEDIUM I.E. EPIMEDIUM BREVICORNU with Potentiate the effect of phosphodiesterase type 5 inhibitor .  

      ►  Reference :-
  • Williamson, E. (2009). Stockley's Herbal Medicines Interaction .. London: Pharmacutical press.

  •   ►  URL -- https://www.stonybrookmedicine.edu/sites/default/files/herbal_medicines_interactions-1.pdf

    ►   Route of Elimination :   Fecal, Renal, Hepatic (Metabolism)
    Ref :-   Book : Martindale    Page : 2367   Edition : 38.  

    ►    Plasma Half-life :   Min value :-   half-lives of sildenafil and the N-desmethyl metabolite are about 4 hours.,    Max value :-   NA
    Ref :-   Book : Martindale    Page : 2367   Edition : 38.  

    ►    Peak Plasma Concentration :   Min value :-   within 30 to 120 minutes;,    Max value :-   NA
    Ref :-   Book : Martindale    Page : 2367   Edition : 38.