ADVERSE REACTIONS

There are two versions of the drug: a version that can be taken as needed Cialis 5-mg daily dosing is the only PDE5 inhibitor dose approved for treating an enlarged prostate; improving ED symptoms is an added benefit of the daily dose. Because of the “as needed” version of tadalafil, some users may find this option more convenient. The downside, however, is that side effects tend to last longer too.

• Sildenafil citrate 100mg tablets are prescribed for erectile dysfunction and pulmonary hypertension.
• The medication enhances the effects of nitric oxide for improved blood flow.
• Do not use sildenafil if you are allergic to citrate or other components.
• Commonly prescribed in adult men experiencing erectile difficulty.
• Patients should avoid heavy meals before taking sildenafil to optimize absorption.
• Do not barge to take sildenafil if on certain blood pressure medications.
• Sildenafil may cause skin rashes or allergic reactions in sensitive individuals.
• Inform your doctor if you experience vision impairment or sudden hearing loss.
• Use caution when operating machinery or driving after taking sildenafil.
• This medication has been effective for many men, but results vary.
• Do not combine sildenafil with other ED medications without medical advice.
• Always keep sildenafil out of children's reach to prevent accidental ingestion.

The main difference between generic sildenafil and Viagra is marketing. The main ingredient in Viagra is sildenafil, meaning that the drugs are essentially the same. However, Viagra is marketed and prescribed strictly for erectile dysfunction, sildenafil from canada while generic sildenafil can be prescribed for PAH as well. Viagra is also known as “the little blue pill” because of its blue color, while generic sildenafil tends to be a white color.

Dose Adjustments

Typical dosage: 5 or 20 mg, taken three times per day about 4 to 6 hours apart Maximum dosage: 20 mg, taken three times per day about 4 to 6 hours apart This drug shouldn’t be used in children younger than 18 years of age. Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. Always speak with your doctor or pharmacist about dosages that are right for you. Sildenafil oral tablet is used for short-term treatment of ED and long-term treatment of PAH.

How should I store sildenafil?

It comes with serious risks if you don’t take it as prescribed. If you stop taking the drug suddenly or don’t take it at all: For ED: Your ED symptoms won’t improve. For PAH: Your condition won’t improve and may get worse. Also, you won’t be able to exercise. If you miss doses or don’t take the drug on schedule: For ED: Your ED symptoms won’t improve. Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. You should always consult your doctor or other healthcare professional before taking any medication. All content on this page has been medically reviewed by: Hassan Thwaini, Clinical Pharmacist and Copywriter, Master of Pharmacy (MPharm) on 30 March, 2026. Sildenafil is an effective treatment for erectile dysfunction. It contains the same active ingredient as branded alternatives. Sildenafil works by encouraging more blood to flow to the penis, ensuring a strong erection when you need one. It’s effective for 82% of men.1 Find the clinically proven ED treatment that suits you best. No names, no logos, no delivery fee.

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Store sildenafil tablets at room temperature between 59°F and 86°F (15°C and 30°C). Don’t store this medication in moist or sildenafil 100mg hexal damp areas, such as bathrooms. A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Professional resources

When flying, never put it into a checked bag. Keep it in your carry-on bag. Don’t worry about airport X-ray machines. You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you. BSc (Hons) MBBS MRCGP AFHEA MA (Hons) AFMCP “Efficacy and Safety of Sildenafil Citrate for Treatment of Erectile Dysfunction in a Population With Associated Organic Risk Factors.” Journal of Andrology (2013). “Efficacy and Safety of Sildenafil Citrate for Treatment of Erectile Dysfunction in a Population With Associated Organic Risk Factors.” Journal of Andrology (2013). Answer a few simple questions to get the treatment you need.

The most common sexual dysfunctions in men include lack of interest, premature ejaculation and erectile dysfunction. The latter affects 52% of men between the ages of 40 and 70, including mild, moderate and complete forms of ED.

Warnings & Precautions

How to tell if the drug is working: For ED: You should be able to get and maintain an erection when sexually aroused. For PAH: You should be able to exercise more easily. Your doctor will also check you to determine if this drug is working. Keep these considerations in mind if your doctor prescribes sildenafil for you. You can take this drug with or without food.

How Viagra Works

You can cut or crush the tablet. When you take the drug depends on the condition being treated:For ED: You can take this drug at any time of day.For PAH: Take this drug three times per day about 4–6 hours apart. Take it at the same time every day. For ED: You can take this drug at any time of day. For PAH: Take this drug three times per day about 4–6 hours apart. Organic or physical causes for sexual dysfunction in men include vascular, hormonal and neurologic factors. Concerning vascular causes, the risk factors for atherosclerosis (including smoking, high blood pressure, diabetes (diabetics do not respond well to pills like sildenafil (Viagra)) and high cholesterol are ALSO risk factors for erectile dysfunction. Since a straddle injury or use of a narrow saddle can obstruct and impair arteries to the penis, bicycle riding is also considered a risk factor for erectile dysfunction.

See also:

Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold. If you’re taking this drug for PAH, your doctor may monitor your blood pressure and pulse regularly. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it. Many insurance companies require prior authorization for this drug.

Viagra for ED

This means your doctor may need to get approval from your insurance company before your insurance company will pay for the prescription. Sildenafil under the brand name Viagra is prescribed to treat erectile dysfunction by increasing blood flow to the penis during arousal. Sildenafil under the brand name Revatio is often prescribed to help adults with PAH get more exercise by treating their condition. What if I forget to take it? If you are taking Revatio and you forget to take your scheduled dose, take it as soon as possible. Little attention has been paid to endocrine factors. Testosterone modulates desire, arousal and orgasmic function.

Frequently asked questions

However, you should never double your dosage. If you completely miss a dose and it’s time for the next dose, skip the one you missed. Are there any safety measures I should take before using this drug? Like most medications, there are precautions you should take before using this drug. Make sure you talk with your doctor about: any other drugs, medications, herbs, or supplements you take or plan to take any medical conditions or surgeries you have or plan to have if you are pregnant or plan to become pregnant There are other drugs available to treat your condition. Concerning the orgasmic response, testosterone modulates the integrity of genital sensory receptors.

2. Upsides

For PAH: This medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times. If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include: If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

Sildenafil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

What to do if you miss a dose: For ED: Take your dose 30 minutes to 4 hours before your next sexual activity. For PAH: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects. Concerning the arousal response, decreased testosterone blood levels can influence the efficacy of sildenafil (Viagra). If the sildenafil response is not reliably improving erection, the physician should first check if the patient is taking the pill correctly. The physician should also check the patient’s testosterone level. One investigator in Italy gave testosterone to patients with low testosterone who did not respond to sildenafil (Viagra).

• Sildenafil citrate 100mg tablets are a popular choice for ED treatment.
• The medication helps achieve and maintain an erection suitable for intercourse.
• Use can be affected by other health conditions; always disclose complete medical history.
• Sildenafil has specific storage instructions to maintain effectiveness.
• The medication should be taken approximately one hour before needed.
• Patients should avoid combining sildenafil with certain antihypertensives.
• Expect some common side effects like headache and warmth.
• Report any serious side effects such as chest pain or sudden vision loss.
• Do not take sildenafil if you have low blood pressure or are on blood thinners.
• It is essential to follow your healthcare provider’s dosing guidelines.
• Do not use sildenafil if you are currently on nitrates for chest pain.
• Ensure understanding of all precautions before starting treatment.

When daily testosterone was given, subsequent sildenafil (Viagra) use resulted in IIEF (the International Index of Erectile Function questionnaire used to determine erectile function) scores improving significantly. Other risk factors for erectile dysfunction include neurologic problems (multiple sclerosis, stroke), depression and medications for treating diabetes, hypertension, heart disease and depression. There are many oral therapies for erectile dysfunction, but the only approved medication in the US is the PDE 5 enzyme inhibitor sildenafil (Viagra). Unapproved therapies, some of which are available in the US and some elsewhere, some of which have data to prove efficacy and some not, include tadalafil (Cialis), vardenafil (Levitra), yohimbine, phentolamine, trazodone, apomorphine and neutraceuticals. PDE5 inhibitors act to relax penile erectile tissues with sexual stimulation thus enhancing your ability to get an erection.

• Sildenafil citrate 100mg tablets are used globally for erectile treatment.
• The medication’s onset of action is typically within 30-60 minutes.
• Patients should avoid heavy or greasy foods before taking sildenafil.
• Do not consume alcohol as it can impair the effectiveness.
• Sildenafil does not cure erectile dysfunction but helps manage symptoms.
• Always take medication exactly as your doctor directs.
• Side effects can include dizziness, flushing, and nasal congestion.
• Check with your doctor if you are on other medications for safety.
• The medication is not suitable for patients with eye conditions like retinitis pigmentosa.
• Use sildenafil responsibly to prevent misuse or adverse health effects.
• Be aware of and report any persistent pain or changes in vision.
• Keep all medical appointments to monitor treatment progress.

Sildenafil (Viagra) is effective for all sorts of erectile dysfunction in 69% of people. Why is there a need for another pill?

• Sildenafil citrate 100mg tablets are used to treat erectile dysfunction in men.
• The usual recommended dose is 100mg taken about an hour before activity.
• Sildenafil works by increasing blood flow to the penis during arousal.
• This medication should not be used with nitrate drugs due to risk of dangerous interactions.
• Common side effects include headache, flushing, upset stomach, and nasal congestion.
• Do not take sildenafil more than once in a 24-hour period.
• Sildenafil can cause hypotension, especially when combined with certain medications.
• It is available by prescription and should be used under medical supervision.
• Patients with heart problems should consult their doctor before use.
• Sildenafil should be stored at room temperature, away from moisture and heat.
• Alcohol can increase the risk of side effects when taking sildenafil.
• Sildenafil may cause vision changes such as blue tinge or increased sensitivity to light.

In some cases the erection is not hard enough, sometimes sildenafil (Viagra) just doesn’t work. Structurally vardenafil (Levitra) is similar to sildenafil, while tadalafil (Cialis) is very different.

Pregnancy & Lactation

Some may be better suited for you than others. Talk with your doctor about other drug options that may work for you. Sildenafil and tadalafil are alike because they both can treat ED and PAH. However, tadalafil has a few distinctions from sildenafil. Tadalafil is the generic name for the erectile dysfunction drug Cialis. Vardenafil (Levitra) is almost 10 times more biochemically potent than sildenafil, therefore a lower dose is needed to facilitate the penile erection, potentially resulting in less side effects. Selectivity is the ability of the drug to attach to the specific enzyme PDE 5 found in penile tissues.