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Why it's used

Sildenafil is a prescription medicine that is used to treat the inability to keep an enlarged and rigid state of the penis during sexual activity. This condition is known as erectile dysfunction or ED. This medicine helps by relaxing muscles and therefore allowing the flow of blood into the penis. This helps a man to keep the penis in an enlarged and rigid state during sexual excitement.
Phosphodiesterase 5 Inhibitors
Sildenafil belongs to the Phosphodiesterase 5 Inhibitors class of medicines. Phosphodiesterase 5 (PDE5) inhibitors are a group of targeted therapy medicines that used to treat people with high blood pressure. PDE 5 inhibitors are also used to treat erectile dysfunction.

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How to use

Read the medicine guide provided by your pharmacist, your doctor, or the medicine company. If you have any questions related to Sildenafil, ask your doctor or pharmacist. Use Sildenafil as per the instructions provided by your doctor.
Sildenafil is eaten with or without food. Avoid taking this medicine with the high-fat meal as it may reduce the effectiveness of the medicine. Sildenafil is eaten around 1 hour before sexual activity. Sildenafil is not effective in the absence of sexual arousal.

Typical Dosage

The typical dose of Sildenafil for adults is 50 mg once a day (not more than 100 mg in one day). The maximum dose for adult patients of Sildenafil is 100 mg per day. It takes 1 hour for this medicine to start its action. This medicine is not known to be addictive or habit-forming.
This medicine should be used on an as-needed basis.

Talk to Your Doctor

Discuss with your doctor if you develop new or worsening symptoms. Discuss with your doctor if decreased blood pressure, chest pain, nausea, dizziness, decrease or loss of hearing, have an erection lasting more than 4 hours, and have loss of vision in one or both eyes. If you have any kidney disease, a lower dose will be prescribed. If you have issues with the health of your liver, a lower dose will be prescribed by the doctor.
Your doctor may prescribe a lower starting dose of this medicine to understand the impact on the body. Please follow your doctor's recommendations. Taking a higher dose of this medicine may increase the risk of side-effects. A lower dose of this medicine may be recommended to reduce the risk of side-effects. Older patients may see an increase in the incidence of side-effects. As a result, a lower dose may be recommended for older patients.

Use in Children

The safety and effectiveness of using Sildenafil in children has not been established.

Possibly safe with Alcohol

Sildenafil is known to be safe with alcohol.
Medicines may be recommended for uses other than those listed in the medicine guide. You should not use Sildenafil for conditions or symptoms for which it was not prescribed. Do not give Sildenafil to other people, even if they have the same conditions or symptoms that you have. The use of this medicine without the advice of a doctor may cause harm.


Follow storage instructions on the product package if available. Store Sildenafil store at 15-30°C (59-86°F) temperature, away from excess moisture, and away from light. Store this medicine away from children and pets.

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How to take Sildenafil

Your dose may depend on several personal factors. You should consult with your doctor to find out the dose that is best for you. The dose of Sildenafil depends on the following factors:
  • patient's age
  • patient's health
  • the health of the patient's liver
  • the health of the patient's kidneys
  • medicines recommended by your doctor
  • any other medicines in use
  • response to treatment

Sildenafil Dosage

Dosage for erectile dysfunction

  • Recommended: 50 mg per day
  • Initial: 25 mg per day
  • Maximum: 100 mg per day
Older Adults (65 years or higher)
  • Recommended: 50 mg/day
  • Initial: 25 mg/day
  • Maximum: 100 mg/day

Minimum Age

18 years


Strength: 25 mg, 50 mg and 100 mg

Special Instructions

Oral formulations
Use not more than one tablet in a day with or without meals.


What to do if you overdose on Sildenafil?
In case of overdose, standard supportive measures should be adopted.
If you think you have overdosed on Sildenafil, call a poison control center immediately. You can look up the poison control center information from the Poison Center Finder at

Precautions while using Sildenafil

Before you use Sildenafil, tell your doctor of your medical and health history including the following:
  • bleeding disorder
  • blood circulation problems
  • cancer of blood cells (leukemia)
  • cancer of white blood cells (multiple myeloma)
  • chest pain (angina)
  • deformed penis shape
  • diabetes
  • eye disease
  • have had blockage of veins in the lungs (PVOD)
  • heart failure
  • high blood pressure
  • high cholesterol
  • history of heart surgery
  • kidney or liver disease
  • low blood pressure
  • palpitation
  • recently have had dehydration
  • red blood cells disorder (sickle cell anemia)
  • rigid state of the penis that lasts for more than 4 hours during sexual excitement (priapism)
  • severe vision loss
  • stomach ulcers
  • stroke
Before you use Sildenafil, discuss with your doctor if you are allergic to it or its ingredients. Your doctor may prescribe an alternative medicine and update your medical records to record this information.
The use of this medicine may change blood pressure. Patients with known history of heart disease or stroke should monitor their blood pressure.


Sildenafil can make you feel sleepy. Be careful when using any machinery, driving a vehicle, or doing any other activity that needs you to be fully alert. The consumption of alcohol with Sildenafil can worsen the sleepiness. Sildenafil may cause rarely seizures in some people. If you perform any activities where a loss of consciousness may cause harm to you (or others), you should discuss with your doctor.

Use in Pregnancy

Pregnant/breastfeeding women should not use this medicine. Sildenafil is not for use by women.

Use while Breastfeeding

Women who are breastfeeding a baby should not use this medicine.


Sildenafil is known to be safe with alcohol.

Side-effects in Older Patients

Sildenafil may cause increased incidence of side-effects in older patients.

Sildenafil Side-effects

The following side-effects may commonly occur when using Sildenafil. If any of these side-effects worsen or last for a long time, you should consult with your doctor:
The following severe side-effects may also occur when using Sildenafil:
  • Erections lasting more than 4 hours (known as, priapism) (permanent injury to the penis)
    Symptoms: painfully enlarged and rigid state of the penis for more than 4 hours
    If this happens, you should contact your doctor right away.
  • Sudden vision loss in one or both eyes
    The medicine should be discontinued and you should contact your doctor right away.
  • Heart disease (palpitation, or heart attack) (possibly fatal)
    If this happens, contact your doctor right away and stop taking medicine.
  • Sudden loss or decrease in hearing
    Symptoms: dizziness ringing in the ears
    The medicine should be discontinued and you should contact your doctor right away.
Your doctor has prescribed Sildenafil because they judge that the benefit is greater than the risk posed by side-effects. Many people using this medicine do not have serious side-effects. This page does not list all possible side-effects of Sildenafil.
If you experience side-effects or notice other side-effects not listed above, contact your doctor for medical advice. You may also report side-effects to your local food and drug administration authority. You can look up the drug authority contact information from the Drug Authority Finder at


Non-Arteritic Anterior Ischemic Optic Neuropathy

Patients with NAION (non-arteritic anterior ischemic optic neuropathy) risk factors may face a sudden loss of vision in one or both eyes. This medicine should be used with caution and if a loss of vision occurs, the medicine should be discontinued.

Loss of Hearing

Usage of this medicine may cause a sudden decrease or loss of hearing, ringing in ears (tinnitus), and dizziness. If you experience any of these symptoms, you should should stop the use of the medicine.

Existing Heart Disease

Patients with any prior history of heart diseases may have a higher risk of heart attack. Such patients should use this medicine with caution.

Prolonged Erection

Some patients may have a prolonged erection lasting more than 4 hours, or a painful erection lasting more than 6 hours. In this happens, you should consult with your doctor immediately.

Low Blood Pressure

In patients using low blood pressure medicines and Sildenafil together, the blood pressure can drop significantly. This can result in dizziness, lightheadedness, and fainting. Such patients should first establish a stable regimen for their low blood pressure medicines and then start at a lower dose for Sildenafil.

Use of Ritonavir

In patients using Sildenafil along with Ritonavir, it can result in decreased blood pressure, loss of consciousness, and prolonged erection. For such patients, lower dosage of Sildenafil is recommended.

Other Erectile Dysfunction Medicines

The combined use of Sildenafil with other erectile dysfunction medicines may result in further lowering of the blood pressure. Combined use of multiple erectile dysfunction medicines is not recommended.

Interactions with Sildenafil

When two or more medicines are taken together, it can change how the medicines work and increase the risk of side-effects. In medical terms, this is called as a Drug Interaction.
This page does not contain all the possible interactions of Sildenafil. Share a list of all medicines that you use with your doctor and pharmacist. Do not start, stop, or change the dose of any medicines without the approval of your doctor.


Sildenafil may interact with organic nitrates or nitrites, which are used to treat chest pain and heart disease. Using Sildenafil along with nitrates can result in harmful effects on the heart. Hence, organic nitrates or nitrites should not be used in combination with this medicine.


There may be an interaction of Sildenafil with alpha-blockers, which are medicines used to lower the blood pressure and treat prostate enlargement in men. Using Sildenafil with alpha-blockers can result in reduced blood pressure. In such cases, the patient should be given the lowest dose of Sildenafil, which is 25 mg.

Calcium Channel Blockers

Sildenafil interacts with amlodipine, which is a medicine used to lower the blood pressure. Taking these two drugs together can result in an abnormal blood pressure. As a result, Amlodipine and Sildenafil should be used together with caution.

CYP3A4 Inhibitors

Special instructions need to be followed while taking this medicine along with ritonavir and other CYP3A4 inhibitors, which are medicines used in the treatment of HIV/AIDS. When these two drugs are given together, CYP3A4 inhibitors cause the levels of Sildenafil in the blood to increase several folds. A starting dose of 25 mg of Sildenafil should be considered in patients taking CYP3A4 inhibitors.


Traveling With Medication

  • Ensure that you carry enough doses of each of your prescription medicines to last the entire trip. The best place to store your medicines is in the carry on baggage. However, while flying, if carrying liquid medicines, make sure you do not go over the limits imposed for carry-on liquids.
  • While traveling overseas, make sure that you can carry each of your prescription medicines legally to your destination country. One way to ensure this is by checking with your destination country's embassy or website.
  • Make sure that you carry each of your medicines in their original packaging, which should typically include your name and address, and the details of the prescribing doctor.
  • If your travel involves crossing time zones, and you are required to take your medicine as per a fixed schedule, make sure that you adjust for the change in time.

Expired Medication

Taking a single dose of expired Sildenafil is unlikely to cause a side-effect. However, please discuss with your doctor or pharmacist, if you feel unwell or sick. An expired medicine may become ineffective in treating your prescribed conditions. To be on the safe side, it is important not to use an expired drug. You are much safer by always keeping a fresh supply of unexpired medicines.

Safe Disposal of Medication

  • If there are disposal instructions on the package, please follow the instructions.
  • If there are medicine take-back programs in your country, you should contact the respective authority to arrange for the disposal of the medicine. For example, in the USA, the Drug Enforcement Administration regularly hosts National Prescription Drug Take-Back events.
  • If there are no take-back programs, mix the medicine with dirt and place them in a sealed plastic bag. Throw the plastic bag in your household trash. Separately, remove all personal information including the prescription label from the medicine packaging and then dispose off the container.
  • If specifically indicated on the medicine package that it needs to be flushed down the toilet when no longer needed, perform the required step.
This page provides information for Sildenafil .
Erectile Dysfunction
Sexual Health
Sexual Problems in Men
Sexually Transmitted Diseases

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