11 DESCRIPTION

If you are taking sildenafil for erectile dysfunction or pulmonary arterial hypertension, it’s possible to experience side effects.

• Certain health conditions, like retinitis pigmentosa, may contraindicate use of sildenafil.
• Always disclose your full medical history to your healthcare provider.
• Monitor for any unusual symptoms after taking the medication.

Most side effects are mild to moderate in severity. If you’re experiencing symptoms of severe side effects while taking sildenafil, talk with your doctor right away.

Warnings & Precautions

• Also, the use of CYP3A4 or P450 inhibitors (which are the cytochromes responsible for Viagra metabolism), greatly increases the risk of negative side effects. ADVERSE EFFECTS- • HEADACHE •NASAL CONGESTION • DIZZINESS • FLUSHING • FALL IN BP • LOOSE MOTIONS • IMPAIRMENT OF COLOUR DISCRIMINATION PHARMACOKINETICS • Sildenafil citrateis rapidly absorbed after oral administration - Total Bioavailability: 40% • Its pharmacokinetics are dose proportional over the recommended range • Sildenafil citrate is metabolized mainly by hepatic metabolism and excreted mainly in the feces. Sildenafil, sold under the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. [4][8] It is also sometimes used off-label for the treatment of certain symptoms in secondary Raynaud's phenomenon. [9] It is unclear if it sildenafil 20 mg tablets is effective for treating sexual dysfunction in females.

Does sildenafil cause different side effects in females?

[8] It can be taken orally (swallowed by mouth), intravenously (injection into a vein), or through the sublingual route (dissolved under the tongue). [8][10] Onset when taken orally is typically within twenty minutes and lasts for about two hours. Common side effects include headaches, heartburn, and flushed skin. [8] Caution is advised in those with cardiovascular disease. [8] Rare but serious side effects include vision problems, hearing loss, and prolonged erection (priapism) that can lead to damage to the penis.

Are you currently using Sildenafil (Viagra, Revatio)?

[8] Sildenafil should not be taken by people on nitric oxide donors such as nitroglycerin, as this may result in a serious drop in blood pressure. Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that promotes breakdown of cGMP, which regulates blood flow in the penis. [8] It requires sexual arousal to work, and does not by itself cause or increase sexual arousal. [8] It also results in dilation of the blood vessels in the lungs. Pfizer originally discovered the medication in 1989 while looking for a treatment for angina. If you’d like to learn more about sildenafil, talk with your doctor or pharmacist.

Product	Dosage	Quantity + Bonus	Price
Viagra Generic	150mg	60 + 4 Pills	111.25€ 105.95€	Buy
Kamagra Soft Tabs	100mg	12 Pills	57.55€ 54.81€	Buy
Viagra Generic	50mg	20 Pills	40.52€ 38.59€	Buy
Kamagra Oral Jelly	100mg	30 + 5 Sachets	136.20€ 129.71€	Buy
Viagra Generic	50mg	60 + 4 Pills	83.93€ 79.93€	Buy
Viagra Generic	50mg	120 + 6 Pills	129.64€ 123.47€	Buy
Kamagra	100mg	84 + 6 Pills	264.44€ 251.85€	Buy
Kamagra Polo	100mg	32 Pills	125.88€ 119.89€	Buy
Viagra Generic	25mg	120 + 6 Pills	125.56€ 119.58€	Buy
Viagra Generic	200mg	60 + 4 Pills	125.19€ 119.23€	Buy
Kamagra	100mg	32 Pills	121.24€ 115.47€	Buy
Viagra Generic	100mg	20 Pills	45.58€ 43.41€	Buy
Viagra Generic	50mg	30 + 4 Pills	54.26€ 51.68€	Buy
Viagra Generic	200mg	360 + 10 Pills	481.98€ 459.03€	Buy
Viagra Generic	50mg	90 + 6 Pills	107.37€ 102.26€	Buy
Viagra Generic	50mg	180 + 8 Pills	158.82€ 151.26€	Buy
Kamagra Polo	100mg	272 + 12 Pills	622.94€ 593.28€	Buy

They can help answer any questions you have about side effects from taking the drug. A generic drug and its brand-name version contain the same active ingredient, so they’re expected to have the same side effects.

Medication Class	Potential Effect	Notes
Nitrates	Severe hypotension	Do not co-administer
CYP3A4 inhibitors (e.g., ketoconazole)	Increased sildenafil levels	Dose adjustment may be necessary
Alpha-blockers	Risk of hypotension	Use with caution
Other Vasodilators	Additive blood pressure lowering	Monitor closely

Referring to the following articles about sildenafil and Viagra can provide you with additional information: For details about other aspects of sildenafil, refer to this article. To learn how sildenafil compares with Viagra, read this article. If you’d like to learn about sildenafil and cost, see this article. For details about your condition, see our hypertension hub. You can also view our men’s health hub and this list of erectile dysfunction and premature ejaculation articles. Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date.

• Do not take sildenafil if you are on nitrate medications for chest pain.
• Using both can cause a dangerous drop in blood pressure.
• Always inform your doctor about all medications you are taking.

However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects.

Property	Details	Notes
Absorption	Rapid, peaks in approximately 1 hour	Takes about 30-60 minutes
Distribution	Widely distributed in tissues	Bound to plasma proteins
Metabolism	Liver (primarily CYP3A4 enzyme)	Metabolized into active metabolites
Half-life	Approximately 4 hours	Duration of effect varies
Excretion	Mainly in feces; some in urine	Clearance affected by age

The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

In case of emergency/overdose

[11] It was approved for medical use in the United States and in the European Union in 1998. [5][8][11][12] In 2023, it was the 151st most commonly prescribed medication in the United States, with more than 3 million prescriptions. [13][14] It is available as a generic medication. [15][16] In the United Kingdom, it is available as a pharmacy medicine. The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete sexual intercourse).

Why is the use of Sildenafil Citrate contraindicated with nitrates?

Its use is now one of the standard treatments for erectile dysfunction, including for males with diabetes mellitus. Tentative evidence suggests that sildenafil may help males who experience antidepressant-induced erectile dysfunction. While sildenafil improves some markers of disease in people with pulmonary arterial hypertension, it does not appear to affect the risk of death or serious side effects. Sildenafil and other PDE5 inhibitors are used off-label to alleviate vasospasm and treat severe ischemia and ulcers in fingers and toes for people with secondary Raynaud's phenomenon;[9][21] these drugs have moderate efficacy for reducing the frequency and duration of vasospastic episodes. [9] As of 2016,[update] their role more generally in Raynaud's was not clear.

What should I tell my healthcare provider before taking sildenafil?

Sildenafil has shown some potential for improving exercise performance at high altitudes. However, its overall efficacy is not clear. Sildenafil has been studied for high-altitude pulmonary edema (HAPE), but its use is currently not recommended for that indication. In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, indigestion, nasal congestion, and impaired vision, including photophobia and blurred vision. [4] Some sildenafil users have complained of seeing everything tinted blue (cyanopsia). Sildenafil Citrate DR. MANOJKUMAR SINGH 1ST YR PG PHYSICAL MEDICINE AND REHABILITATION PMCH PATNA HISTORY- • Pfizer originallysought for a PDE inhibitor that might act as a new antihypertensive and antianginal drug. • Studies were done to see what side effects would come from increased dosages. Volunteers reported back with side effects like head aches, visual problems, and prolongment of penile erections.

Non-medical use

[24] This cyanopsia can be explained because sildenafil, while selective for PDE5, does have some affinity for PDE6, which is the phosphodiesterase found in the retina. Patients thus taking the drug may experience colorvision abnormalities. Some complained of blurriness and loss of peripheral vision. In July 2005, the US Food and Drug Administration (FDA) updated labeling for tadalafil (Cialis), vardenafil (Levitra), and sildenafil (Viagra) to reflect a small number of post-marketing reports of sudden vision loss, while acknowledging that "...it is not possible to determine whether these oral medicines for erectile dysfunction were the cause of the loss of eyesight or whether the problem is related to other factors such as high blood pressure or diabetes, or to a combination of these problems. "[25] A careful review of pooled data from clinical trials containing well documented information about the dose and duration of exposure to the drug for a large number of patients, yields no evidence for an increased risk of non-arteritic anterior ischemic optic neuropathy or other adverse ocular events associated with PDE5 inhibitor use. • According to the British Press, but not Pfizer, Peter Dunn and Albert Wood invented sildenafil. • Hydrolysis with NaOH • Nitration with fuming Nitric Acid • Carboxamide formation with refluxing thionyl chloride/ NH4OH • Reduction of Nitro group to Amino • Acylation with 2-ethoxybenzoyle chloride • Cyclization • Sulfonation to the chlorosulfonyl derivative • Condesation with 1-methylpiperazine MEDICAL USES- *ERECTILE DYSFUNCTION *PULMONARYHYPERTENSION * prevention and treatment of high-altitude pulmonary edema associated with altitude sickness.

• Common side effects include headaches, flushing, and nasal congestion.
• Serious side effects are rare but may include vision changes or prolonged erections.
• Report any adverse reactions to a healthcare provider immediately.

NONMEDICAL USE- * Recreationaluse belief that the drug increases libido, improves sexual performance, or permanently increases penis size *Jet lag research * Sports * Analogs Acetildenafil is a structural analog of sildenafil, one of the PDE5 inhibitors found in a number of "herbal" aphrodisiac products sold over-the-counter. ERECTILE DYSFUCTION- • Initialdose: 50 mg orally once a day, as needed, 1 hour prior to sexual activity • Maintenance: 25 to 100 mg orally once a day, as needed, 1 hour prior to sexual activity.

8.6 Patients with Hepatic Impairment

Rare but serious adverse effects found through postmarketing surveillance include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss. [4] In October 2007, the FDA announced that the labeling for all PDE5 inhibitors, including sildenafil, required a more prominent warning of the potential risk of sudden hearing loss. HYPERTENSION DOSE- •Initial dose: 5 or 20 mg orally three times a day, 4 to 6 hours apart • -Maximum dose: 20 mg orally three times a day • Injection: • -Initial dose: 2.5 or 10 mg IV bolus three times a day. Nitric oxide (NO) in the corpus cavernosum of the penis binds to guanylate cyclase receptors, which results in increased levels of cGMP, leading to smooth muscle relaxation (vasodilation) of the intimal cushions of the helicine arteries. This smooth muscle relaxation leads to vasodilation and increased inflow of blood into the spongy tissue of the penis, causing an erection CONTRAINDICATION- • When takingnitric oxide donors, organic nitrites and nitrates, such as glyceryl trinitrate (nitroglycerin), sodium nitroprusside, amyl nitrite. • In men for whom sexual intercourse is inadvisable due to cardiovascular risk factors • Severe hepatic impairment (decreased liver function) • Severe impairment in renal function • Hypotension (low blood pressure) • Recent stroke or heart attack • Hereditary degenerative retinal disorders (including genetic disorders of retinal phosphodiesterases) • Because sildenafilis a vasodilator (although mainly locally), it needs to be used cautiously because it lowers blood pressure. • Viagra should not be given to patients who are taking nitrates, because nitrates are also a strong vasodilator. The use of both could cause major heart problems. • Also, the use of CYP3A4 or P450 inhibitors (which are the cytochromes responsible for Viagra metabolism), greatly increases the risk of negative side effects. ADVERSE EFFECTS- • HEADACHE •NASAL CONGESTION • DIZZINESS • FLUSHING • FALL IN BP • LOOSE MOTIONS • IMPAIRMENT OF COLOUR DISCRIMINATION PHARMACOKINETICS • Sildenafil citrateis rapidly absorbed after oral administration - Total Bioavailability: 40% • Its pharmacokinetics are dose proportional over the recommended range • Sildenafil citrate is metabolized mainly by hepatic metabolism and excreted mainly in the feces. Sildenafil, sold under the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. [4][8] It is also sometimes used off-label for the treatment of certain symptoms in secondary Raynaud's phenomenon. [9] It is unclear if it sildenafil 20 mg tablets is effective for treating sexual dysfunction in females. [8] It can be taken orally (swallowed by mouth), intravenously (injection into a vein), or through the sublingual route (dissolved under the tongue). [8][10] Onset when taken orally is typically within twenty minutes and lasts for about two hours. Common side effects include headaches, heartburn, and flushed skin. [8] Caution is advised in those with cardiovascular disease. [8] Rare but serious side effects include vision problems, hearing loss, and prolonged erection (priapism) that can lead to damage to the penis. [8] Sildenafil should not be taken by people on nitric oxide donors such as nitroglycerin, as this may result in a serious drop in blood pressure. Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that promotes breakdown of cGMP, which regulates blood flow in the penis. [8] It requires sexual arousal to work, and does not by itself cause or increase sexual arousal. [8] It also results in dilation of the blood vessels in the lungs. Pfizer originally discovered the medication in 1989 while looking for a treatment for angina. [11] It was approved for medical use in the United States and in the European Union in 1998.

Patient Group	Recommended Dose	Notes
Adults (18-65)	50 mg prior to activity	Max once per day
Elderly (>65)	25-50 mg as needed	Adjust based on tolerability
Patients with Liver Impairment	Start at 25 mg	May need dose reduction
Patients on CYP3A4 inhibitors	Lower dose	Due to increased plasma levels

[5][8][11][12] In 2023, it was the 151st most commonly prescribed medication in the United States, with more than 3 million prescriptions. [13][14] It is available as a generic medication. [15][16] In the United Kingdom, it is available as a pharmacy medicine.

• 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.

The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete sexual intercourse). Its use is now one of the standard treatments for erectile dysfunction, including for males with diabetes mellitus. Tentative evidence suggests that sildenafil may help males who experience antidepressant-induced erectile dysfunction.

5.4 Visual Loss

If you are taking sildenafil for erectile dysfunction or pulmonary arterial hypertension, it’s possible to experience side effects. Most side effects are mild to moderate in severity. If you’re experiencing symptoms of severe side effects while taking sildenafil, talk with your doctor right away. If you’d like to learn more about sildenafil, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

How it works

A generic drug and its brand-name version contain the same active ingredient, so they’re expected to have the same side effects. Referring to the following articles about sildenafil and Viagra can provide you with additional information: For details about other aspects of sildenafil, refer to this article. To learn how sildenafil compares with Viagra, read this article. If you’d like to learn about sildenafil and cost, see this article. For details about your condition, see our hypertension hub.

Raynaud's phenomenon

You can also view our men’s health hub and this list of erectile dysfunction and premature ejaculation articles. Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. While sildenafil improves some markers of disease in people with pulmonary arterial hypertension, it does not appear to affect the risk of death or serious side effects. Sildenafil and other PDE5 inhibitors are used off-label to alleviate vasospasm and treat severe ischemia and ulcers in fingers and toes for people with secondary Raynaud's phenomenon;[9][21] these drugs have moderate efficacy for reducing the frequency and duration of vasospastic episodes. [9] As of 2016,[update] their role more generally in Raynaud's was not clear. Sildenafil has shown some potential for improving exercise performance at high altitudes. However, its overall efficacy is not clear. Sildenafil has been studied for high-altitude pulmonary edema (HAPE), but its use is currently not recommended for that indication. In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, indigestion, nasal congestion, and impaired vision, including photophobia and blurred vision. [4] Some sildenafil users have complained of seeing everything tinted blue (cyanopsia). [24] This cyanopsia can be explained because sildenafil, while selective for PDE5, does have some affinity for PDE6, which is the phosphodiesterase found in the retina. Patients thus taking the drug may experience colorvision abnormalities. Some complained of blurriness and loss of peripheral vision. In July 2005, the US Food and Drug Administration (FDA) updated labeling for tadalafil (Cialis), vardenafil (Levitra), and sildenafil (Viagra) to reflect a small number of post-marketing reports of sudden vision loss, while acknowledging that "...it is not possible to determine whether these oral medicines for erectile dysfunction were the cause of the loss of eyesight or whether the problem is related to other factors such as high blood pressure or diabetes, or to a combination of these problems.

Frequently asked questions

The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses. Sildenafil Citrate DR. MANOJKUMAR SINGH 1ST YR PG PHYSICAL MEDICINE AND REHABILITATION PMCH PATNA HISTORY- • Pfizer originallysought for a PDE inhibitor that might act as a new antihypertensive and antianginal drug. • Studies were done to see what side effects would come from increased dosages. Volunteers reported back with side effects like head aches, visual problems, and prolongment of penile erections.

Regional issues

• According to the British Press, but not Pfizer, Peter Dunn and Albert Wood invented sildenafil. • Hydrolysis with NaOH • Nitration with fuming Nitric Acid • Carboxamide formation with refluxing thionyl chloride/ NH4OH • Reduction of Nitro group to Amino • Acylation with 2-ethoxybenzoyle chloride • Cyclization • Sulfonation to the chlorosulfonyl derivative • Condesation with 1-methylpiperazine MEDICAL USES- *ERECTILE DYSFUNCTION *PULMONARYHYPERTENSION * prevention and treatment of high-altitude pulmonary edema associated with altitude sickness. NONMEDICAL USE- * Recreationaluse belief that the drug increases libido, improves sexual performance, or permanently increases penis size *Jet lag research * Sports * Analogs Acetildenafil is a structural analog of sildenafil, one of the PDE5 inhibitors found in a number of "herbal" aphrodisiac products sold over-the-counter. ERECTILE DYSFUCTION- • Initialdose: 50 mg orally once a day, as needed, 1 hour prior to sexual activity • Maintenance: 25 to 100 mg orally once a day, as needed, 1 hour prior to sexual activity. HYPERTENSION DOSE- •Initial dose: 5 or 20 mg orally three times a day, 4 to 6 hours apart • -Maximum dose: 20 mg orally three times a day • Injection: • -Initial dose: 2.5 or 10 mg IV bolus three times a day.

Serious Side Effects

Nitric oxide (NO) in the corpus cavernosum of the penis binds to guanylate cyclase receptors, which results in increased levels of cGMP, leading to smooth muscle relaxation (vasodilation) of the intimal cushions of the helicine arteries. This smooth muscle relaxation leads to vasodilation and increased inflow of blood into the spongy tissue of the penis, causing an erection CONTRAINDICATION- • When takingnitric oxide donors, organic nitrites and nitrates, such as glyceryl trinitrate (nitroglycerin), sodium nitroprusside, amyl nitrite. • In men for whom sexual intercourse is inadvisable due to cardiovascular risk factors • Severe hepatic impairment (decreased liver function) • Severe impairment in renal function • Hypotension (low blood pressure) • Recent stroke or heart attack • Hereditary degenerative retinal disorders (including genetic disorders of retinal phosphodiesterases) • Because sildenafilis a vasodilator (although mainly locally), it needs to be used cautiously because it lowers blood pressure. • Viagra should not be given to patients who are taking nitrates, because nitrates are also a strong vasodilator. The use of both could cause major heart problems. "[25] A careful review of pooled data from clinical trials containing well documented information about the dose and duration of exposure to the drug for a large number of patients, yields no evidence for an increased risk of non-arteritic anterior ischemic optic neuropathy or other adverse ocular events associated with PDE5 inhibitor use. Rare but serious adverse effects found through postmarketing surveillance include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss. [4] In October 2007, the FDA announced that the labeling for all PDE5 inhibitors, including sildenafil, required a more prominent warning of the potential risk of sudden hearing loss.