zafirlukast will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
- Sildenafil citrate 50 mg is used to treat erectile dysfunction in men.
- The typical starting dose is 50 mg taken about one hour before activity.
- It should not be used more than once per 24 hours.
acetazolamideacetazolamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. acetazolamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
8.5 Geriatric Use
Can I take Sildenafil Citrate as often as I want?
anastrozoleanastrozole will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. anastrozole will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
- Sildenafil citrate was initially developed for hypertension and angina.
- It was later discovered to be effective for erectile dysfunction.
- The drug was approved by the FDA for ED treatment in 1998.
cyclophosphamidecyclophosphamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
- Sildenafil tablets may cause flushing or warmth sensation during use.
- Some users experience indigestion or mild dizziness.
- These effects are generally temporary and resolve spontaneously.
cyclophosphamide will increase the level or effect of sildenafil by affecting hepatic/intestinal 150mg sildenafil for sale enzyme CYP3A4 metabolism. drospirenonedrospirenone will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Generic | 200mg | 20 Pills | 61.69€ 58.75€ | |
| Viagra Generic | 200mg | 60 + 4 Pills | 125.19€ 119.23€ | |
| Viagra Generic | 200mg | 30 + 2 Pills | 83.07€ 79.11€ | |
| Viagra Generic | 150mg | 360 + 10 Pills | 423.48€ 403.31€ | |
| Viagra Generic | 150mg | 90 + 6 Pills | 147.18€ 140.17€ | |
| Kamagra Polo | 100mg | 32 Pills | 125.88€ 119.89€ | |
| Viagra Generic | 50mg | 10 Pills | 26.87€ 25.59€ | |
| Viagra Generic | 50mg | 20 Pills | 40.52€ 38.59€ | |
| Kamagra Soft Tabs | 100mg | 60 + 4 Pills | 180.59€ 171.99€ | |
| Kamagra | 100mg | 84 + 6 Pills | 264.44€ 251.85€ | |
| Viagra Generic | 150mg | 180 + 10 Pills | 236.46€ 225.20€ | |
| Kamagra Oral Jelly | 100mg | 220 + 18 Sachets | 662.24€ 630.70€ | |
| Kamagra Polo | 100mg | 120 + 6 Pills | 327.15€ 311.57€ | |
| Viagra Generic | 100mg | 60 + 4 Pills | 96.36€ 91.77€ | |
| Viagra Generic | 25mg | 90 + 6 Pills | 105.03€ 100.03€ |
drospirenone will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. labetalolsildenafil increases effects of labetalol sildenafil citrate tables by pharmacodynamic synergism.
8.7 Patients with Renal Impairment
Vybrique Oral Film
sildenafil increases effects of labetalol by pharmacodynamic synergism.
8.2 Lactation
Are there reviews from people who had side effects with 50-mg or 100-mg sildenafil tablets?
larotrectiniblarotrectinib will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
| Question | Answer | Notes |
|---|---|---|
| Can sildenafil citrate 50 mg be used recreationally? | No, it is a prescription medication for specific conditions | Risk of serious side effects |
| How long does the effect last? | Generally 4-6 hours | Varies between individuals |
| Is it safe to take with alcohol? | Alcohol may reduce effectiveness and increase side effects | Use caution |
| Can women take sildenafil citrate? | Not approved for women; safety and efficacy not established | Consult healthcare provider |
| What should I do if I experience side effects? | Seek medical advice; stop medication if severe reactions occur | Contact doctor promptly |
larotrectinib will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
- People with certain health conditions should consult their doctor before use.
- Conditions include heart disease, low blood pressure, or kidney/liver issues.
- Adjustments to dosage may be necessary based on health status.
macitentanmacitentan increases levels of sildenafil by unspecified interaction mechanism.
What to avoid
Missed Dose
Systemic exposure of steady-state sildenafil (20 mg TID) increased by 15% during coadministration of macitentan (10 mg/day); this change is not considered clinically relevant.
| Reaction | Incidence (%) | Severity | Management |
|---|---|---|---|
| Headache | 15% | Mild | Analgesics as needed |
| Dyspepsia | 10% | Mild | Dietary adjustments |
| Nasal congestion | 8% | Mild | Decongestants if severe |
| Visual disturbances | 2% | Mild | Usually reversible |
| Dizziness | 5% | Mild | Sit or lie down immediately |
macitentan liquid sildenafil citrate increases levels of sildenafil by unspecified interaction mechanism.
About the Company
zafirlukast will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. acetazolamideacetazolamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. acetazolamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. anastrozoleanastrozole will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. anastrozole will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
Rakshita Garg
cyclophosphamidecyclophosphamide will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. cyclophosphamide will increase the level or effect of sildenafil by affecting hepatic/intestinal 150mg sildenafil for sale enzyme CYP3A4 metabolism. drospirenonedrospirenone will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. drospirenone will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. labetalolsildenafil increases effects of labetalol sildenafil citrate tables by pharmacodynamic synergism. Possible additive vasorelaxation, leading to low blood pressure.
Mechanism of action
sildenafil increases effects of labetalol by pharmacodynamic synergism. larotrectiniblarotrectinib will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. larotrectinib will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. macitentanmacitentan increases levels of sildenafil by unspecified interaction mechanism. Systemic exposure of steady-state sildenafil (20 mg TID) increased by 15% during coadministration of macitentan (10 mg/day); this change is not considered clinically relevant.
Discover the Benefits of ABHA Card registration
macitentan liquid sildenafil citrate increases levels of sildenafil by unspecified interaction mechanism. Possible additive vasorelaxation, leading to low blood pressure. 50-mg doseHeadache (21%)Flushing (19%)100-mg dose H5Headache (28%)Flushing (18%)Dyspepsia (17%)Abnormal vision (11%) 25-mg doseFlushing (10%)Nasal congestion (4%)Dyspepsia (3%)Back pain (3%)Dizziness (3%)Myalgia (2%)Nausea (2%)Abnormal vision (1%)Rash (1%) 50-mg doseDyspepsia (9%)Nasal congestion (4%)Back pain (4%)Dizziness (4%)Nausea (3%)Abnormal vision (2%)Myalgia (2%)Rash (2%) 100-mg doseNasal congestion (9%)Back pain (4%)Myalgia (4%)Nausea (3%)Dizziness (3%)Rash (3%) <2% with potential causal relationshipBody as a whole: Face edema, photosensitivity reaction, shock, asthenia, pain, chills, accidental fall, abdominal pain, allergic reaction, chest pain, accidental injuryCardiovascular: Angina pectoris, AV block, migraine, syncope, tachycardia, palpitation, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, cardiomyopathyDigestive: Vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, liver function tests abnormal, rectal hemorrhage, gingivitisHemic and lymphatic: Anemia and leukopeniaMetabolic and nutritional: Thirst, edema, gout, unstable diabetes, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemic reaction, hypernatremiaMusculoskeletal: Arthritis, arthrosis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, synovitisNervous: Ataxia, hypertonia, neuralgia, neuropathy, paresthesia, tremor, vertigo, depression, insomnia, somnolence, abnormal dreams, reflexes decreased, hypesthesiaRespiratory: Asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, sputum increased, cough increasedSkin and appendages: Urticaria, herpes simplex, pruritus, sweating, skin ulcer, contact dermatitis, exfoliative dermatitisSpecial senses: Sudden decrease or loss of hearing, mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, ear pain, eye hemorrhage, cataract, dry eyesUrogenital: Cystitis, nocturia, urinary frequency, breast enlargement, urinary incontinence, abnormal ejaculation, genital edema and anorgasmia Body as a whole: Face edema, photosensitivity reaction, shock, asthenia, pain, chills, accidental fall, abdominal pain, allergic reaction, chest pain, accidental injury Cardiovascular: Angina pectoris, AV block, migraine, syncope, tachycardia, palpitation, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, cardiomyopathy Digestive: Vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, liver function tests abnormal, rectal hemorrhage, gingivitis Metabolic and nutritional: Thirst, edema, gout, unstable diabetes, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemic reaction, hypernatremia Musculoskeletal: Arthritis, arthrosis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, synovitis Nervous: Ataxia, hypertonia, neuralgia, neuropathy, paresthesia, tremor, vertigo, depression, insomnia, somnolence, abnormal dreams, reflexes decreased, hypesthesia Respiratory: Asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, sputum increased, cough increased Skin and appendages: Urticaria, herpes simplex, pruritus, sweating, skin ulcer, contact dermatitis, exfoliative dermatitis Special senses: Sudden decrease or loss of hearing, mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, ear pain, eye hemorrhage, cataract, dry eyes Urogenital: Cystitis, nocturia, urinary frequency, breast enlargement, urinary incontinence, abnormal ejaculation, genital edema and anorgasmia Cardiovascular and cerebrovascular: Serious cardiovascular (CV), cerebrovascular, and vascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension, subarachnoid and intracerebral hemorrhages, and pulmonary hemorrhage (most, but not all, of these patients had preexisting CV risk factors) Hemic and lymphatic: vaso-occlusive crisis: In a small, prematurely terminated study of sildenafil in patients with pulmonary arterial hypertension (PAH) secondary to sickle cell disease, vaso-occlusive crises requiring hospitalization were commonly reported Nervous: Seizure, seizure recurrence, anxiety, and transient global amnesia Hearing: Cases of sudden decrease or loss of hearing reported postmarketing in temporal association with PDE5 inhibitors Ocular: Diplopia, temporary vision loss/decreased vision, ocular redness or bloodshot appearance, ocular burning, ocular swelling/pressure, increased intraocular pressure, retinal edema, retinal vascular disease or bleeding, and vitreous traction/detachment Nonarteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision (reported rarely) Soluble guanylate cyclase (sGC) stimulators (eg, riociguat); concomitant use can cause hypotension Coadministration with nitrates (either regularly and/or intermittently) and nitric oxide donors Consistent with the effects of PDE5 inhibition on the nitric oxide/cyclic guanosine monophosphate pathway, PDE5 inhibitors may potentiate the hypotensive effects of nitrates A suitable time interval following PDE5 dosing for the safe administration of nitrates or nitric oxide donors has not been determined Elicits vasodilatory properties, resulting in mild and transient decreases in blood pressure; monitor for hypotension Use with caution in patients with anatomic deformation of penis (eg, angulation, cavernosal fibrosis, or Peyronie disease), conditions potentially predisposing to priapism (eg, sickle cell anemia, multiple myeloma, or leukemia), cardiovascular disease, bleeding disorders, active peptic ulcer disease, liver disease, renal impairment, multidrug antihypertensive regimens, retinitis pigmentosa, concomitant use of CYP3A4 inhibitors Pulmonary vasodilators may significantly worsen cardiovascular status of patients with pulmonary veno-occlusive disease Sudden decrease or loss of hearing, which may be accompanied by tinnitus and dizziness Stop sildenafil and seek medical care if a sudden loss of vision occurs in 1 or both eyes, which could be a sign of nonarteritic anterior ischemic optic neuropathy (NAION); use with caution, and only when the anticipated benefits outweigh the risks, most patients had underlying anatomic or vascular risk factors for developing NAION, including low cup to disc ratio (“crowded disc”); advise patients to seek immediate medical attention in the event of a sudden loss of vision May cause dose-related impairment of color discrimination; use in patients with retinitis pigmentosa not recommended Potential for cardiac risk with sexual activity in patients with preexisting cardiovascular disease; therefore, treatment for erectile dysfunction generally should not be instituted in men for whom sexual activity is inadvisable because of their underlying cardiovascular status Evaluate underlying causes of erectile dysfunction or BPH before initiating therapy In small, prematurely terminated study of patients with PAH secondary to sickle-cell disease, vaso-occlusive crises requiring hospitalization were more commonly reported by patients who received sildenafil than by those randomized to placebo; effectiveness of sildenafil in PAH secondary to sickle-cell anemia has not been established; the clinical relevance to men treated for erectile dysfunction with sildenafil is not known Epistaxis occurred in 13% of patients with PAH secondary to connective tissue disease (eg, scleroderma); this effect was not seen in idiopathic PAH; incidence was also higher in those receiving concomitant PO vitamin K antagonist therapy (9%) than in those not receiving such therapy (2%) CYP3A substrate (major route); CYP2C9 substrate (minor route) NitratesContraindicatedConsistent with its known effects on the nitric oxide/cGMP pathway, sildenafil was shown to potentiate the hypotensive effects of nitrates Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil was shown to potentiate the hypotensive effects of nitrates Strong CYP3A inhibitorsViagra: Modify dose; not to exceed single dose of 25 mg/48 hrRevatio: Not recommendedCoadministration increases systemic exposure of sildenafil and risk of adverse effects Viagra: Modify dose; not to exceed single dose of 25 mg/48 hr Coadministration increases systemic exposure of sildenafil and risk of adverse effects Moderate-to-strong CYP3A inducersRevatio: Modify dose; upward dose titration may be needed if coadministeredCoadministration with moderate-to-strong CYP3A inducers (eg, bosentan) decreases the sildenafil exposure and possibly reduces efficacy Revatio: Modify dose; upward dose titration may be needed if coadministered Coadministration with moderate-to-strong CYP3A inducers (eg, bosentan) decreases the sildenafil exposure and possibly reduces efficacy Other PDE5 inhibitorsAvoidAdditive adverse effects may occur if coadministered with other PDE5 inhibitors (eg, avanafil, tadalafil, vardenafil) Additive adverse effects may occur if coadministered with other PDE5 inhibitors (eg, avanafil, tadalafil, vardenafil) Alpha-blockers or antihypertensivesModify dose/cautionCoadministration may increase risk of hypotensionParticularly with higher doses used for erectile dysfunction Particularly with higher doses used for erectile dysfunction Limited 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 mother and fetus from untreated pulmonary arterial hypertension Pregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death Limited published data from a case report describe presence of sildenafil and its active metabolite in human milk; there is insufficient information about effects of sildenafil on breastfed infant and no information on effects of sildenafil on milk production; limited clinical data during lactation preclude a clear determination of risk of drug to an infant during lactation Controlled studies in pregnant women show no evidence of fetal risk. 50-mg doseHeadache (21%)Flushing (19%)100-mg dose H5Headache (28%)Flushing (18%)Dyspepsia (17%)Abnormal vision (11%) 25-mg doseFlushing (10%)Nasal congestion (4%)Dyspepsia (3%)Back pain (3%)Dizziness (3%)Myalgia (2%)Nausea (2%)Abnormal vision (1%)Rash (1%) 50-mg doseDyspepsia (9%)Nasal congestion (4%)Back pain (4%)Dizziness (4%)Nausea (3%)Abnormal vision (2%)Myalgia (2%)Rash (2%) 100-mg doseNasal congestion (9%)Back pain (4%)Myalgia (4%)Nausea (3%)Dizziness (3%)Rash (3%) <2% with potential causal relationshipBody as a whole: Face edema, photosensitivity reaction, shock, asthenia, pain, chills, accidental fall, abdominal pain, allergic reaction, chest pain, accidental injuryCardiovascular: Angina pectoris, AV block, migraine, syncope, tachycardia, palpitation, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, cardiomyopathyDigestive: Vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, liver function tests abnormal, rectal hemorrhage, gingivitisHemic and lymphatic: Anemia and leukopeniaMetabolic and nutritional: Thirst, edema, gout, unstable diabetes, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemic reaction, hypernatremiaMusculoskeletal: Arthritis, arthrosis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, synovitisNervous: Ataxia, hypertonia, neuralgia, neuropathy, paresthesia, tremor, vertigo, depression, insomnia, somnolence, abnormal dreams, reflexes decreased, hypesthesiaRespiratory: Asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, sputum increased, cough increasedSkin and appendages: Urticaria, herpes simplex, pruritus, sweating, skin ulcer, contact dermatitis, exfoliative dermatitisSpecial senses: Sudden decrease or loss of hearing, mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, ear pain, eye hemorrhage, cataract, dry eyesUrogenital: Cystitis, nocturia, urinary frequency, breast enlargement, urinary incontinence, abnormal ejaculation, genital edema and anorgasmia Body as a whole: Face edema, photosensitivity reaction, shock, asthenia, pain, chills, accidental fall, abdominal pain, allergic reaction, chest pain, accidental injury Cardiovascular: Angina pectoris, AV block, migraine, syncope, tachycardia, palpitation, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, cardiomyopathy Digestive: Vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, liver function tests abnormal, rectal hemorrhage, gingivitis Metabolic and nutritional: Thirst, edema, gout, unstable diabetes, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemic reaction, hypernatremia Musculoskeletal: Arthritis, arthrosis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, synovitis Nervous: Ataxia, hypertonia, neuralgia, neuropathy, paresthesia, tremor, vertigo, depression, insomnia, somnolence, abnormal dreams, reflexes decreased, hypesthesia Respiratory: Asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, sputum increased, cough increased Skin and appendages: Urticaria, herpes simplex, pruritus, sweating, skin ulcer, contact dermatitis, exfoliative dermatitis Special senses: Sudden decrease or loss of hearing, mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, ear pain, eye hemorrhage, cataract, dry eyes Urogenital: Cystitis, nocturia, urinary frequency, breast enlargement, urinary incontinence, abnormal ejaculation, genital edema and anorgasmia Cardiovascular and cerebrovascular: Serious cardiovascular (CV), cerebrovascular, and vascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension, subarachnoid and intracerebral hemorrhages, and pulmonary hemorrhage (most, but not all, of these patients had preexisting CV risk factors) Hemic and lymphatic: vaso-occlusive crisis: In a small, prematurely terminated study of sildenafil in patients with pulmonary arterial hypertension (PAH) secondary to sickle cell disease, vaso-occlusive crises requiring hospitalization were commonly reported Nervous: Seizure, seizure recurrence, anxiety, and transient global amnesia Hearing: Cases of sudden decrease or loss of hearing reported postmarketing in temporal association with PDE5 inhibitors Ocular: Diplopia, temporary vision loss/decreased vision, ocular redness or bloodshot appearance, ocular burning, ocular swelling/pressure, increased intraocular pressure, retinal edema, retinal vascular disease or bleeding, and vitreous traction/detachment Nonarteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision (reported rarely) Soluble guanylate cyclase (sGC) stimulators (eg, riociguat); concomitant use can cause hypotension Coadministration with nitrates (either regularly and/or intermittently) and nitric oxide donors Consistent with the effects of PDE5 inhibition on the nitric oxide/cyclic guanosine monophosphate pathway, PDE5 inhibitors may potentiate the hypotensive effects of nitrates A suitable time interval following PDE5 dosing for the safe administration of nitrates or nitric oxide donors has not been determined Elicits vasodilatory properties, resulting in mild and transient decreases in blood pressure; monitor for hypotension Use with caution in patients with anatomic deformation of penis (eg, angulation, cavernosal fibrosis, or Peyronie disease), conditions potentially predisposing to priapism (eg, sickle cell anemia, multiple myeloma, or leukemia), cardiovascular disease, bleeding disorders, active peptic ulcer disease, liver disease, renal impairment, multidrug antihypertensive regimens, retinitis pigmentosa, concomitant use of CYP3A4 inhibitors Pulmonary vasodilators may significantly worsen cardiovascular status of patients with pulmonary veno-occlusive disease Sudden decrease or loss of hearing, which may be accompanied by tinnitus and dizziness Stop sildenafil and seek medical care if a sudden loss of vision occurs in 1 or both eyes, which could be a sign of nonarteritic anterior ischemic optic neuropathy (NAION); use with caution, and only when the anticipated benefits outweigh the risks, most patients had underlying anatomic or vascular risk factors for developing NAION, including low cup to disc ratio (“crowded disc”); advise patients to seek immediate medical attention in the event of a sudden loss of vision May cause dose-related impairment of color discrimination; use in patients with retinitis pigmentosa not recommended Potential for cardiac risk with sexual activity in patients with preexisting cardiovascular disease; therefore, treatment for erectile dysfunction generally should not be instituted in men for whom sexual activity is inadvisable because of their underlying cardiovascular status Evaluate underlying causes of erectile dysfunction or BPH before initiating therapy In small, prematurely terminated study of patients with PAH secondary to sickle-cell disease, vaso-occlusive crises requiring hospitalization were more commonly reported by patients who received sildenafil than by those randomized to placebo; effectiveness of sildenafil in PAH secondary to sickle-cell anemia has not been established; the clinical relevance to men treated for erectile dysfunction with sildenafil is not known Epistaxis occurred in 13% of patients with PAH secondary to connective tissue disease (eg, scleroderma); this effect was not seen in idiopathic PAH; incidence was also higher in those receiving concomitant PO vitamin K antagonist therapy (9%) than in those not receiving such therapy (2%) CYP3A substrate (major route); CYP2C9 substrate (minor route) NitratesContraindicatedConsistent with its known effects on the nitric oxide/cGMP pathway, sildenafil was shown to potentiate the hypotensive effects of nitrates Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil was shown to potentiate the hypotensive effects of nitrates Strong CYP3A inhibitorsViagra: Modify dose; not to exceed single dose of 25 mg/48 hrRevatio: Not recommendedCoadministration increases systemic exposure of sildenafil and risk of adverse effects Viagra: Modify dose; not to exceed single dose of 25 mg/48 hr Coadministration increases systemic exposure of sildenafil and risk of adverse effects Moderate-to-strong CYP3A inducersRevatio: Modify dose; upward dose titration may be needed if coadministeredCoadministration with moderate-to-strong CYP3A inducers (eg, bosentan) decreases the sildenafil exposure and possibly reduces efficacy Revatio: Modify dose; upward dose titration may be needed if coadministered Coadministration with moderate-to-strong CYP3A inducers (eg, bosentan) decreases the sildenafil exposure and possibly reduces efficacy Other PDE5 inhibitorsAvoidAdditive adverse effects may occur if coadministered with other PDE5 inhibitors (eg, avanafil, tadalafil, vardenafil) Additive adverse effects may occur if coadministered with other PDE5 inhibitors (eg, avanafil, tadalafil, vardenafil) Alpha-blockers or antihypertensivesModify dose/cautionCoadministration may increase risk of hypotensionParticularly with higher doses used for erectile dysfunction Particularly with higher doses used for erectile dysfunction Limited 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 mother and fetus from untreated pulmonary arterial hypertension Pregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death Limited published data from a case report describe presence of sildenafil and its active metabolite in human milk; there is insufficient information about effects of sildenafil on breastfed infant and no information on effects of sildenafil on milk production; limited clinical data during lactation preclude a clear determination of risk of drug to an infant during lactation Controlled studies in pregnant women show no evidence of fetal risk.