DRUG INTERACTIONS
Dose up-titration of sildenafil citrate may be needed when initiating treatment with moderate-to-strong CYP3A inducers. Reduce the dose of sildenafil to 20 mg three times a day when discontinuing treatment with moderate-to-strong CYP3A inducers [see Clinical Pharmacology (12.3) and Clinical Studies (14)]. Concomitant use of sildenafil citrate with moderate-to-strong CYP3A inducers (such as bosentan) decreases the sildenafil exposure. 8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummaryLimited published data from randomized controlled trials, case-controlled trials, and case series do not report a clear association with sildenafil and major birth defects, miscarriage, or adverse maternal or fetal outcomes when sildenafil is used during pregnancy.
| Country/Region | Approval Status | Prescription Required | Notes |
|---|---|---|---|
| USA | Approved by FDA | Yes | Prescription only |
| European Union | Approved by EMA | Yes | Prescription required |
| Canada | Approved by Health Canada | Yes | Prescription needed |
| Australia | TGA approval | Yes | Prescription mandatory |
There are risks to the mother and fetus from untreated pulmonary arterial hypertension (see Clinical Considerations). Animal reproduction studies conducted with sildenafil showed no evidence of embryo-fetal toxicity or teratogenicity at doses up to 32- and 65-times the recommended human dose (RHD) of 20 mg three times a day in rats and rabbits, respectively (see Data).The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S.
- Sildenafil 20 mg tablets are supplied in blister packs or bottles.
- Always check the expiration date before use.
- Alcohol may reduce the effectiveness or increase side effects.
- Avoid taking sildenafil with fatty foods for faster absorption.
- Keep out of reach of children to prevent accidental ingestion.
general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.Clinical ConsiderationsDisease-Associated Maternal and/or Embryo/Fetal RiskPregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death.DataAnimal DataNo evidence of teratogenicity, embryotoxicity, or fetotoxicity was observed in pregnant rats or rabbits dosed with sildenafil 200 mg/kg/ day during organogenesis, a level that is, on a mg/m2 basis, 32- and 65-times, respectively, the recommended human dose (RHD) of 20mg three times a day. In a rat pre- and postnatal development study, the no-observed-adverse-effect dose was 30 mg/kg/day (equivalent to 5-times the RHD on a mg/m2 basis).8.2 LactationRisk SummaryLimited published data from a case report describe the presence of sildenafil and its active metabolite in human milk. There is insufficient information about the effects of sildenafil on the breastfed infant and no information on the effects of sildenafil on milk production. Limited clinical data during lactation preclude a clear determination of the risk of sildenafil citrate to an infant during lactation.8.4 Pediatric UseThe safety and effectiveness of sildenafil citrate has not been established in pediatric patients younger than 1 year of age.Pediatric use information is approved for Viatris Specialty LLC’s, REVATIO (sildenafil) tablets. However, due to Viatris Specialty LLC’s marketing exclusivity rights, this drug product is not labeled with that information.8.5 Geriatric UseClinical studies of sildenafil citrate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.
Renal Dose Adjustments
Severe impairment has not been studied [see Clinical Pharmacology (12.3)].8.7 Patients with Renal ImpairmentNo dose adjustment is required (including severe impairment CLcr < 30 mL/min) [see Clinical Pharmacology (12.3)]. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The safety and effectiveness of sildenafil citrate has not been established in pediatric patients younger than 1 year of age.
What Do Patients Say About Sildenafil 20 mg Tablet?
Clinical studies of sildenafil citrate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an sildenafil oral solution elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Clinical Pharmacology (12.3)]. No dose adjustment for mild to moderate impairment is required. Severe impairment has not been studied [see Clinical Pharmacology (12.3)]. No dose adjustment is required (including severe impairment CLcr < 30 mL/min) [see Clinical Pharmacology (12.3)].
Jet lag research
10 OVERDOSAGE In studies with healthy volunteers of single doses up to 800 mg, adverse events were similar to those seen at lower doses but 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. In studies with healthy volunteers of single doses up to 800 mg, adverse events were similar to those seen at lower doses but rates and severities were increased. In cases of overdose, standard supportive measures should be adopted as required. Sildenafil is also marketed as VIAGRA ® for erectile dysfunction.Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo [4,3- d] pyrimidin-5-yl)-4-ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate and has the following structural formula:Sildenafil citrate, USP is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7.Sildenafil tablets, USP are formulated as white to off-white, round shaped film-coated tablets for oral administration. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Clinical Pharmacology (12.3)].8.6 Patients with Hepatic ImpairmentNo dose adjustment for mild to moderate impairment is required.
- Using sildenafil will not cause an erection without sexual stimulation.
- The medication's effectiveness varies among individuals.
- It can be used in men with diabetes-related erectile issues.
- Combining sildenafil with recreational drugs can be dangerous.
- Always consult healthcare providers for personalized advice.
Severe impairment has not been studied [see Clinical Pharmacology (12.3)].8.7 Patients with Renal ImpairmentNo dose adjustment is required (including severe impairment CLcr < 30 mL/min) [see Clinical Pharmacology (12.3)].
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The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The safety and effectiveness of sildenafil citrate has not been established in pediatric patients younger than 1 year of age. Clinical studies of sildenafil citrate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an sildenafil oral solution elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Clinical Pharmacology (12.3)]. No dose adjustment for mild to moderate impairment is required. Severe impairment has not been studied [see Clinical Pharmacology (12.3)].
| Parameter | Details |
|---|---|
| Onset of Action | 30-60 minutes |
| Peak Effect | About 1 hour |
| Duration of Effect | 4-6 hours |
| Factors Influencing | Food intake, alcohol, metabolism |
No dose adjustment is required (including severe impairment CLcr < 30 mL/min) [see Clinical Pharmacology (12.3)]. 10 OVERDOSAGE In studies with healthy volunteers of single doses up to 800 mg, adverse events were similar to those seen at lower doses but 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. In studies with healthy volunteers of single doses up to 800 mg, adverse events were similar to those seen at lower doses but rates and severities were increased. In cases of overdose, standard supportive measures should be adopted as required. Sildenafil is also marketed as VIAGRA ® for erectile dysfunction.Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo [4,3- d] pyrimidin-5-yl)-4-ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate and has the following structural formula:Sildenafil citrate, USP is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7.Sildenafil tablets, USP are formulated as white to off-white, round shaped film-coated tablets for oral administration.
Liver Dose Adjustments
Dose up-titration of sildenafil citrate may be needed when initiating treatment with moderate-to-strong CYP3A inducers. Reduce the dose of sildenafil to 20 mg three times a day when discontinuing treatment with moderate-to-strong CYP3A inducers [see Clinical Pharmacology (12.3) and Clinical Studies (14)]. Concomitant use of sildenafil citrate with moderate-to-strong CYP3A inducers (such as bosentan) decreases the sildenafil exposure. 8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummaryLimited published data from randomized controlled trials, case-controlled trials, and case series do not report a clear association with sildenafil and major birth defects, miscarriage, or adverse maternal or fetal outcomes when sildenafil is used during pregnancy. There are risks to the mother and fetus from untreated pulmonary arterial hypertension (see Clinical Considerations).
Why it’s used
Animal reproduction studies conducted with sildenafil showed no evidence of embryo-fetal toxicity or teratogenicity at doses up to 32- and 65-times the recommended human dose (RHD) of 20 mg three times a day in rats and rabbits, respectively (see Data).The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.Clinical ConsiderationsDisease-Associated Maternal and/or Embryo/Fetal RiskPregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death.DataAnimal DataNo evidence of teratogenicity, embryotoxicity, or fetotoxicity was observed in pregnant rats or rabbits dosed with sildenafil 200 mg/kg/ day during organogenesis, a level that is, on a mg/m2 basis, 32- and 65-times, respectively, the recommended human dose (RHD) of 20mg three times a day. In a rat pre- and postnatal development study, the no-observed-adverse-effect dose was 30 mg/kg/day (equivalent to 5-times the RHD on a mg/m2 basis).8.2 LactationRisk SummaryLimited published data from a case report describe the presence of sildenafil and its active metabolite in human milk.
What are the most common side effects of sildenafil?
There is insufficient information about the effects of sildenafil on the breastfed infant and no information on the effects of sildenafil on milk production. Limited clinical data during lactation preclude a clear determination of the risk of sildenafil citrate to an infant during lactation.8.4 Pediatric UseThe safety and effectiveness of sildenafil citrate has not been established in pediatric patients younger than 1 year of age.Pediatric use information is approved for Viatris Specialty LLC’s, REVATIO (sildenafil) tablets. However, due to Viatris Specialty LLC’s marketing exclusivity rights, this drug product is not labeled with that information.8.5 Geriatric UseClinical studies of sildenafil citrate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Clinical Pharmacology (12.3)].8.6 Patients with Hepatic ImpairmentNo dose adjustment for mild to moderate impairment is required. Each tablet contains sildenafil citrate, USP equivalent to 20 mg of sildenafil.
What special precautions should I follow?
Sildenafil is also marketed as VIAGRA ® for erectile dysfunction.
Does Either Medication Reverse ED?
Similar effects on blood pressure were noted with 25 mg, 50 mg and 100 mg doses of sildenafil, therefore the effects are not related to dose or plasma levels within this dosage range. Larger effects were recorded among patients receiving concomitant nitrates [see Contraindications (4)].Single oral doses of sildenafil up to 100 mg in healthy volunteers produced no clinically relevant effects on ECG. After chronic dosing of 80 mg three times a day to patients with PAH, no clinically relevant effects on ECG were reported.After chronic dosing of 80 mg three times a day sildenafil to healthy volunteers, the largest mean change from baseline in supine systolic and supine diastolic blood pressures was a decrease of 9 mmHg and 8.4 mmHg, respectively.After chronic dosing of 80 mg three times a day sildenafil to patients with systemic hypertension, the mean change from baseline in systolic and diastolic blood pressures was a decrease of 9.4 mmHg and 9.1 mmHg, respectively.After chronic dosing of 80 mg three times a day sildenafil to patients with PAH, lesser reductions than above in systolic and diastolic blood pressures were observed (a decrease in both of 2 mmHg).Effects of Sildenafil Citrate on VisionAt single oral doses of 100 mg and 200 mg, transient dose-related impairment of color discrimination (blue/green) was detected using the Farnsworth-Munsell 100-hue test, with peak effects near the time of peak plasma levels.
Clinical monitoring
How is sildenafil supplied (dosage forms)?
Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo [4,3- d] pyrimidin-5-yl)-4-ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate and has the following structural formula: Sildenafil citrate, USP is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. Sildenafil tablets, USP are formulated as white to off-white, round shaped film-coated tablets for oral administration. Sildenafil, therefore, increases cGMP within pulmonary vascular smooth muscle cells resulting in relaxation.
- Sildenafil was originally developed as a treatment for hypertension.
- The 20 mg dose is considered a moderate dosage.
- It can be part of a comprehensive erectile dysfunction treatment plan.
- Regular use should be monitored by a healthcare professional.
- The medication should not be used with other ED drugs simultaneously.
In patients with PAH, this can lead to vasodilation of the pulmonary vascular bed and, to a lesser degree, vasodilatation in the systemic circulation.Studies in vitro have shown that sildenafil is selective for PDE-5. Its effect is more potent on PDE-5 than on other known phosphodiesterases (10-fold for PDE6, greater than 80-fold for PDE1, greater than 700-fold for PDE2, PDE3, PDE4, PDE7, PDE8, PDE9, PDE10, and PDE11).
What Is Silenafil and How Does It Work?
Each tablet contains sildenafil citrate, USP equivalent to 20 mg of sildenafil. Sildenafil is also marketed as VIAGRA ® for erectile dysfunction. Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo [4,3- d] pyrimidin-5-yl)-4-ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate and has the following structural formula: Sildenafil citrate, USP is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. Sildenafil tablets, USP are formulated as white to off-white, round shaped film-coated tablets for oral administration. Sildenafil, therefore, increases cGMP within pulmonary vascular smooth muscle cells resulting in relaxation.
Pulmonary Arterial Hypertension
In patients with PAH, this can lead to vasodilation of the pulmonary vascular bed and, to a lesser degree, vasodilatation in the systemic circulation.Studies in vitro have shown that sildenafil is selective for PDE-5. Its effect is more potent on PDE-5 than on other known phosphodiesterases (10-fold for PDE6, greater than 80-fold for PDE1, greater than 700-fold for PDE2, PDE3, PDE4, PDE7, PDE8, PDE9, PDE10, and PDE11). The approximately 4,000-fold selectivity for PDE-5 versus PDE3 is important because PDE3 is involved in control of cardiac contractility. Sildenafil is only about 10-fold as potent for PDE-5 compared to PDE6, an enzyme found in the retina and involved in the phototransduction pathway of the retina. This lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma levels [see Clinical Pharmacology (12.2)].In addition to pulmonary vascular smooth muscle and the corpus cavernosum, PDE-5 is also found in other tissues including vascular and visceral smooth muscle and in platelets.
Prior authorization
The inhibition of PDE-5 in these tissues by sildenafil may be the basis for the enhanced platelet anti-aggregatory activity of nitric oxide observed in vitro, and the mild peripheral arterial-venous dilatation in vivo.12.2 PharmacodynamicsEffects of Sildenafil Citrate on Hemodynamic MeasuresPatients on all sildenafil citrate doses achieved a statistically significant reduction in mean pulmonary arterial pressure (mPAP) compared to those on placebo in a study with no background vasodilators [Study 1 in Clinical Studies (14)]. Data on other hemodynamic measures for the sildenafil citrate 20 mg three times a day and placebo dosing regimens is displayed in Table 3. The relationship between these effects and improvements in 6-minute walk distance is unknown.Table 3. Changes from Baseline in Hemodynamic Parameters at Week 12 [mean (95% CI)] for the Sildenafil Citrate 20 mg Three Times a Day and Placebo GroupEffects of Sildenafil Citrate on Blood PressureSingle oral doses of sildenafil 100 mg administered to healthy volunteers produced decreases in supine blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8/5 mmHg). The decrease in blood pressure was most notable approximately 1 to 2 hours after dosing, and was not different from placebo at 8 hours. The approximately 4,000-fold selectivity for PDE-5 versus PDE3 is important because PDE3 is involved in control of cardiac contractility. Sildenafil is only about 10-fold as potent for PDE-5 compared to PDE6, an enzyme found in the retina and involved in the phototransduction pathway of the retina.
What Other Drugs Interact with Sildenafil?
This lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma levels [see Clinical Pharmacology (12.2)].In addition to pulmonary vascular smooth muscle and the corpus cavernosum, PDE-5 is also found in other tissues including vascular and visceral smooth muscle and in platelets. The inhibition of PDE-5 in these tissues by sildenafil may be the basis for the enhanced platelet anti-aggregatory activity of nitric oxide observed in vitro, and the mild peripheral arterial-venous dilatation in vivo.12.2 PharmacodynamicsEffects of Sildenafil Citrate on Hemodynamic MeasuresPatients on all sildenafil citrate doses achieved a statistically significant reduction in mean pulmonary arterial pressure (mPAP) compared to those on placebo in a study with no background vasodilators [Study 1 in Clinical Studies (14)]. Data on other hemodynamic measures for the sildenafil citrate 20 mg three times a day and placebo dosing regimens is displayed in Table 3. The relationship between these effects and improvements in 6-minute walk distance is unknown.Table 3. Changes from Baseline in Hemodynamic Parameters at Week 12 [mean (95% CI)] for the Sildenafil Citrate 20 mg Three Times a Day and Placebo GroupEffects of Sildenafil Citrate on Blood PressureSingle oral doses of sildenafil 100 mg administered to healthy volunteers produced decreases in supine blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8/5 mmHg). The decrease in blood pressure was most notable approximately 1 to 2 hours after dosing, and was not different from placebo at 8 hours. Similar effects on blood pressure were noted with 25 mg, 50 mg and 100 mg doses of sildenafil, therefore the effects are not related to dose or plasma levels within this dosage range. Larger effects were recorded among patients receiving concomitant nitrates [see Contraindications (4)].Single oral doses of sildenafil up to 100 mg in healthy volunteers produced no clinically relevant effects on ECG. After chronic dosing of 80 mg three times a day to patients with PAH, no clinically relevant effects on ECG were reported.After chronic dosing of 80 mg three times a day sildenafil to healthy volunteers, the largest mean change from baseline in supine systolic and supine diastolic blood pressures was a decrease of 9 mmHg and 8.4 mmHg, respectively.After chronic dosing of 80 mg three times a day sildenafil to patients with systemic hypertension, the mean change from baseline in systolic and diastolic blood pressures was a decrease of 9.4 mmHg and 9.1 mmHg, respectively.After chronic dosing of 80 mg three times a day sildenafil to patients with PAH, lesser reductions than above in systolic and diastolic blood pressures were observed (a decrease in both of 2 mmHg).Effects of Sildenafil Citrate on VisionAt single oral doses of 100 mg and 200 mg, transient dose-related impairment of color discrimination (blue/green) was detected using the Farnsworth-Munsell 100-hue test, with peak effects near the time of peak plasma levels.