Drug Interactions with Sildenafil Citrate

[1] Peak plasma concentrations are achieved within 30-120 minutes (median 60 minutes) when taken on an empty stomach; the erectile response is diminished at 4 hours compared with 2 hours after administration.

• Sildenafil citrate tablets are used to treat erectile dysfunction.
• The typical dosage of sildenafil citrate is 150 mg.
• These tablets work by increasing blood flow to the penis.
• Consult a doctor before taking 150 mg sildenafil tablets.

Based on effectiveness and tolerance, the dose subsequently may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg (maximum frequency once per day). [1][28][33][91][93][94][105][161] Evidence from dose-ranging studies indicates that erectile response is greater at 50- or 100-mg doses than at 25 mg.[1][28][33][130][131] Dosage of sildenafil, including both the dose and frequency of use, must be individualized carefully according to the patient's tolerance and erectile response. Concomitant use with protease inhibitors (e.g., ritonavir): An initial sildenafil dose of 25 mg is recommended in patients receiving protease inhibitors. [1][200] When used concomitantly, do not exceed a maximum single sildenafil dose of 25 mg in a 48 hour period and monitor for adverse effects. In patients with hepatic impairment (e.g., cirrhosis), consider reducing the initial dose of sildenafil to 25 mg.[1] In patients with severe renal impairment (creatinine clearance <30 mL/minute), consider reducing the initial dose of sildenafil to 25 mg.[1] In patients >= 65 years of age, consider reducing the initial dose of sildenafil to 25 mg.[1] Concomitant use of organic nitrates (e.g., nitroglycerin) in any form (e.g., orally, sublingually, transmucosally, parenterally), either regularly or intermittently. There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease.

Patient Group	Typical Dose	Special Considerations
Adult Men	150 mg as needed	Take 30-60 minutes before activity
Elderly Patients	75-150 mg based on response	Start at lower dose, monitor side effects
Patients with Liver impairment	Lower dose advised	Adjust based on hepatic function

[1] Therapy for erectile dysfunction (ED), including sildenafil, generally should not be used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status.

What to avoid

[1] The evaluation of ED should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment. Sildenafil doses of 25-100 mg reduce the maximum supine systolic/diastolic blood pressure by an average of about 8.4/5.5 mm Hg within 1-2 hours after administration of the drug in healthy adults, returning to baseline values within 4-8 hours after a dose. Clinicians should consider whether patients with underlying cardiovascular disease could be affected adversely by the vasodilatory activity of selective PDE type 5 inhibitor therapy, especially in combination with sexual activity. Because there are no controlled clinical data establishing the safety and efficacy of sildenafil in the following subpopulations of patients with ED, the drug should be used with caution in those with a recent (within 6 months) myocardial infarction, stroke, or life-threatening arrhythmia; in those with resting hypotension (blood pressure less than 90/50 mm Hg) or hypertension (blood pressure exceeding 170/110 mm Hg); and in those with cardiac failure or coronary artery disease causing unstable angina. [1][31][101][127][144][154][155][159] The possibility of a hypotensive reaction in patients receiving a selective PDE type 5 inhibitor concomitantly with antihypertensive drug therapy should be considered. [28][31][67] The risk of an undesired hypotensive response is of particular concern in patients with congestive heart failure and a borderline low blood volume and low blood pressure status as well as in patients with left-ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis), those oral sildenafil with severely impaired autonomic control of blood pressure, and in those who are receiving a complex, multidrug antihypertensive regimen. [1][67] Some experts state that monitoring of blood pressure during initiation of sildenafil therapy may be useful in identifying patients who may have an undesirable hypotensive response to the drug and is recommended for patients receiving a multidrug antihypertensive regimen and in those with congestive heart failure who have a borderline low blood volume because of concern about the potential consequences on blood pressure.

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[28][67][159] In patients with severe renal impairment, concomitant use of sildenafil and antihypertensive agents should be undertaken with caution. Nonarteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely during postmarketing experience in temporal association with use of all PDE type 5 inhibitors for the treatment of ED. [1][190][191][192][196][197] Most, but not all, of these patients had underlying anatomic or vascular risk factors for the development of NAION, including but not limited to low cup-to-disc ratio (''crowded" optic disc), age (older than 50 years), diabetes mellitus, hypertension, coronary artery disease, hyperlipidemia, and smoking. [1][191][192][196] Available data suggest that the annual incidence of NAION in the general population of men 50 years of age or older is 2.5-11.8 cases per 100,000. [1] Results of an observational study in patients with recent, episodic PDE type 5 inhibitor use (typical of ED treatment) suggest an approximately two-fold increase in the risk of NAION, with a risk estimate of 2.15 within 5 half-lives of such use.

What happens if I miss a dose?

[1] Peak plasma concentrations are achieved within 30-120 minutes (median 60 minutes) when taken on an empty stomach; the erectile response is diminished at 4 hours compared with 2 hours after administration. Based on effectiveness and tolerance, the dose subsequently may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg (maximum frequency once per day). [1][28][33][91][93][94][105][161] Evidence from dose-ranging studies indicates that erectile response is greater at 50- or 100-mg doses than at 25 mg.[1][28][33][130][131] Dosage of sildenafil, including both the dose and frequency of use, must be individualized carefully according to the patient's tolerance and erectile response. Concomitant use with protease inhibitors (e.g., ritonavir): An initial sildenafil dose of 25 mg is recommended in patients receiving protease inhibitors. [1][200] When used concomitantly, do not exceed a maximum single sildenafil dose of 25 mg in a 48 hour period and monitor for adverse effects.

GENERIC NAME OF THE MEDICINAL PRODUCT:

In patients with hepatic impairment (e.g., cirrhosis), consider reducing the initial dose of sildenafil to 25 mg.[1] In patients with severe renal impairment (creatinine clearance <30 mL/minute), consider reducing the initial dose of sildenafil to 25 mg.[1] In patients >= 65 years of age, consider reducing the initial dose of sildenafil to 25 mg.[1] Concomitant use of organic nitrates (e.g., nitroglycerin) in any form (e.g., orally, sublingually, transmucosally, parenterally), either regularly or intermittently. There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. [1] Therapy for erectile dysfunction (ED), including sildenafil, generally should not be used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status. [1] The evaluation of ED should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment. Sildenafil doses of 25-100 mg reduce the maximum supine systolic/diastolic blood pressure by an average of about 8.4/5.5 mm Hg within 1-2 hours after administration of the drug in healthy adults, returning to baseline values within 4-8 hours after a dose. [1] A risk estimate of 2.27 was reported in a similar study.

• Sildenafil citrate was originally developed for pulmonary hypertension.
• It is sold under brand names like Viagra and generics.
• The onset of action usually occurs within 30-60 minutes.
• Maximum effects are typically seen within 2 hours of intake.

Causality assessment is difficult because of the small number of events, the large number of patients receiving PDE type 5 inhibitors, the occurrence of optic neuropathy in a similar population of individuals who have not been exposed to PDE type 5 inhibitors, and plausible alternative causes (e.g., vascular risk factors, anatomic defects). If sudden vision loss or decreased vision occurs in one or both eyes while a patient is receiving a PDE type 5 inhibitor, the patient should discontinue the drug and contact a clinician immediately. Clinicians should discuss the increased risk of NAION with patients who have already experienced NAION in one eye, including whether such individuals could be adversely affected by use of vasodilators, such as PDE type 5 inhibitors.

Before taking this medicine

[1] A risk estimate of 2.27 was reported in a similar study. Causality assessment is difficult because of the small number of events, the large number of patients receiving PDE type 5 inhibitors, the occurrence of optic neuropathy in a similar population of individuals who have not been exposed to PDE type 5 inhibitors, and plausible alternative causes (e.g., vascular risk factors, anatomic defects). If sudden vision loss or decreased vision occurs in one or both eyes while a patient is receiving a PDE type 5 inhibitor, the patient should discontinue the drug and contact a clinician immediately. Clinicians should discuss the increased risk of NAION with patients who have already experienced NAION in one eye, including whether such individuals could be adversely affected by use of vasodilators, such as PDE type 5 inhibitors. [1] Sildenafil should be used with caution for the treatment of ED in these patients and only when the anticipated benefits outweigh the risks.

Cialis Soft Tabs

Although at greater risk for NAION compared to the general population, evidence is insufficient to support screening for "crowded" optic disc in prospective users of PDE type 5 inhibitors for the treatment of ED. Sildenafil should be used with caution in patients with retinitis pigmentosa, a retinal disorder that may be accompanied by a genetic disorder of retinal phosphodiesterases in some patients, since data establishing the safety and efficacy of the drug in these patients currently are lacking. Sudden decrease or loss of hearing, with or without concomitant vestibular manifestations (e.g., tinnitus, dizziness), has been reported in temporal association with use of PDE type 5 inhibitors, including sildenafil. [1] It is unclear whether these otic effects are directly related to PDE type 5 inhibitors or attributed to other underlying risk factors for hearing loss, a combination of these factors, or to other factors. Patients should discontinue sildenafil and seek medical attention immediately if sudden hearing loss or decreased hearing occurs. [1] Sildenafil should be used with caution for the treatment of ED in these patients and only when the anticipated benefits outweigh the risks. Although at greater risk for NAION compared to the general population, evidence is insufficient to support screening for "crowded" optic disc in prospective users of PDE type 5 inhibitors for the treatment of ED. Sildenafil should be used with caution in patients with retinitis pigmentosa, a retinal disorder that may be accompanied by a genetic disorder of retinal phosphodiesterases in some patients, since data establishing the safety and efficacy of the drug in these patients currently are lacking.

Usual Adult Dose for Erectile Dysfunction

Prolonged erection (exceeding 4 hours) and priapism (painful erection exceeding 6 hours) have been reported infrequently during postmarketing surveillance with sildenafil. [1][31][127][131][139][146][147] Because of the risk of penile tissue damage and permanent loss of potency if priapism is not treated immediately, patients should be warned to seek immediate medical attention if an erection persists for longer than 4 hours. Sildenafil should be used with caution in patients with anatomic deformation of the penis (such as angulation, cavernosal fibrosis, or Peyronie's disease) and in patients who have conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia). Caution is advised when PDE type 5 inhibitors are co-administered with α-adrenergic blocking agents; blood pressure may be lowered significantly and in some patients, symptomatic hypotension sildenafil 45 mg chewable tablets (e.g., dizziness, lightheadedness, fainting) may occur. [1] Patients who demonstrate hemodynamic instability during therapy with an α-adrenergic blocking agent alone are at increased risk for symptomatic hypotension with concomitant use of a PDE type 5 inhibitor.

Usual Pediatric Dose for:

In patients who exhibit hemodynamic instability while receiving an α-adrenergic blocking agent, use caution. [1] Patients should be stable on an α-adrenergic blocking agent prior to initiation of sildenafil, and sildenafil should be administered at the lowest possible dose. [1] In patients receiving an optimal dose of sildenafil, initiate the α-adrenergic blocking agent at the lowest dose. Concomitant administration of ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC). [1] Data are limited; decreased blood pressure, syncope, and prolonged erection have been reported in some healthy volunteers exposed to high doses of sildenafil (200-800 mg). Sudden decrease or loss of hearing, with or without concomitant vestibular manifestations (e.g., tinnitus, dizziness), has been reported in temporal association with use of PDE type 5 inhibitors, including sildenafil. [1] It is unclear whether these otic effects are directly related to PDE type 5 inhibitors or attributed to other underlying risk factors for hearing loss, a combination of these factors, or to other factors.

Warnings Related To Cenforce Medicine

Clinicians should consider whether patients with underlying cardiovascular disease could be affected adversely by the vasodilatory activity of selective PDE type 5 inhibitor therapy, especially in combination with sexual activity. Because there are no controlled clinical data establishing the safety and efficacy of sildenafil in the following subpopulations of patients with ED, the drug should be used with caution in those with a recent (within 6 months) myocardial infarction, stroke, or life-threatening arrhythmia; in those with resting hypotension (blood pressure less than 90/50 mm Hg) or hypertension (blood pressure exceeding 170/110 mm Hg); and in those with cardiac failure or coronary artery disease causing unstable angina. [1][31][101][127][144][154][155][159] The possibility of a hypotensive reaction in patients receiving a selective PDE type 5 inhibitor concomitantly with antihypertensive drug therapy should be considered. [28][31][67] The risk of an undesired hypotensive response is of particular concern in patients with congestive heart failure and a borderline low blood volume and low blood pressure status as well as in patients with left-ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis), those oral sildenafil with severely impaired autonomic control of blood pressure, and in those who are receiving a complex, multidrug antihypertensive regimen. [1][67] Some experts state that monitoring of blood pressure during initiation of sildenafil therapy may be useful in identifying patients who may have an undesirable hypotensive response to the drug and is recommended for patients receiving a multidrug antihypertensive regimen and in those with congestive heart failure who have a borderline low blood volume because of concern about the potential consequences on blood pressure.

Is Viagra dosage based on age or weight?

[28][67][159] In patients with severe renal impairment, concomitant use of sildenafil and antihypertensive agents should be undertaken with caution. Nonarteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely during postmarketing experience in temporal association with use of all PDE type 5 inhibitors for the treatment of ED. [1][190][191][192][196][197] Most, but not all, of these patients had underlying anatomic or vascular risk factors for the development of NAION, including but not limited to low cup-to-disc ratio (''crowded" optic disc), age (older than 50 years), diabetes mellitus, hypertension, coronary artery disease, hyperlipidemia, and smoking. [1][191][192][196] Available data suggest that the annual incidence of NAION in the general population of men 50 years of age or older is 2.5-11.8 cases per 100,000. [1] Results of an observational study in patients with recent, episodic PDE type 5 inhibitor use (typical of ED treatment) suggest an approximately two-fold increase in the risk of NAION, with a risk estimate of 2.15 within 5 half-lives of such use. Patients should discontinue sildenafil and seek medical attention immediately if sudden hearing loss or decreased hearing occurs. Prolonged erection (exceeding 4 hours) and priapism (painful erection exceeding 6 hours) have been reported infrequently during postmarketing surveillance with sildenafil. [1][31][127][131][139][146][147] Because of the risk of penile tissue damage and permanent loss of potency if priapism is not treated immediately, patients should be warned to seek immediate medical attention if an erection persists for longer than 4 hours.

• Some patients may experience priapism, a prolonged erection.
• Discontinue use and seek medical attention if this occurs.
• Sildenafil tablets are available in other strengths if needed.
• The medication is not suitable for those with heart disease.

Sildenafil should be used with caution in patients with anatomic deformation of the penis (such as angulation, cavernosal fibrosis, or Peyronie's disease) and in patients who have conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia).

Region	Typical Price per 150 mg Tablet	Notes
North America	$10 - $20	Depending on brand and pharmacy
Europe	€8 - €18	Variations among countries
Asia	$2 - $8	Generics more affordable

Caution is advised when PDE type 5 inhibitors are co-administered with α-adrenergic blocking agents; blood pressure may be lowered significantly and in some patients, symptomatic hypotension sildenafil 45 mg chewable tablets (e.g., dizziness, lightheadedness, fainting) may occur.

Country	Status	Notes
USA	Approved by FDA	Prescription-only medication
UK	Prescription required	Manufactured under regulatory standards
Canada	Approved for ED and PAH	Prescription-based

[1] Patients who demonstrate hemodynamic instability during therapy with an α-adrenergic blocking agent alone are at increased risk for symptomatic hypotension with concomitant use of a PDE type 5 inhibitor. In patients who exhibit hemodynamic instability while receiving an α-adrenergic blocking agent, use caution.

• The medication may interact with antibiotics like erythromycin.
• Patients with eye disorders should consult their doctor before use.
• Sildenafil citrate tablets are often used recreationally as well.
• Overuse or misuse can lead to health complications.

[1] Patients should be stable on an α-adrenergic blocking agent prior to initiation of sildenafil, and sildenafil should be administered at the lowest possible dose. [1] In patients receiving an optimal dose of sildenafil, initiate the α-adrenergic blocking agent at the lowest dose. Concomitant administration of ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC). [1] Data are limited; decreased blood pressure, syncope, and prolonged erection have been reported in some healthy volunteers exposed to high doses of sildenafil (200-800 mg).

Frequently asked questions

[1] Use sildenafil with caution in patients receiving ritonavir; reduced sildenafil dosage is recommended to decrease the chance of adverse reactions to sildenafil. Bleeding events have been reported in patients taking sildenafil for ED. [1] In patients with bleeding disorders or active peptic ulcers, sildenafil should be used with caution since safety of the drug has not been established. [1][27][33][67][131] The possibility that sildenafil could potentiate the effects of certain other drugs exhibiting antiplatelet activity should be considered. Safety and efficacy have not been established for use of sildenafil in combination with other PDE type 5 inhibitors or other treatments for ED; such combinations may further lower blood pressure and are not recommended.

Alcohol interaction warning

Patients should be advised that use of sildenafil provides no protection against sexually transmitted diseases and they should be counseled regarding protective measures to guard against such transmission. [1] Use sildenafil with caution in patients receiving ritonavir; reduced sildenafil dosage is recommended to decrease the chance of adverse reactions to sildenafil. Bleeding events have been reported in patients taking sildenafil for ED. [1] In patients with bleeding disorders or active peptic ulcers, sildenafil should be used with caution since safety of the drug has not been established. [1][27][33][67][131] The possibility that sildenafil could potentiate the effects of certain other drugs exhibiting antiplatelet activity should be considered. Safety and efficacy have not been established for use of sildenafil in combination with other PDE type 5 inhibitors or other treatments for ED; such combinations may further lower blood pressure and are not recommended. Patients should be advised that use of sildenafil provides no protection against sexually transmitted diseases and they should be counseled regarding protective measures to guard against such transmission.