Medically reviewed by Jessica Swirble, PharmD
Last updated on April 2, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Sildenafil is a medication classified as a phosphodiesterase type 5 (PDE5) inhibitor. It is primarily used to treat erectile dysfunction (ED) and pulmonary arterial hypertension (PAH).
Sildenafil is used to treat conditions such as:
It may also have off-label uses as determined by your healthcare provider.
Sildenafil works by inhibiting the enzyme PDE5, which regulates blood flow in the penis. By inhibiting PDE5, sildenafil helps to increase blood flow, leading to improved erectile function. In PAH, it relaxes blood vessels in the lungs, reducing the workload on the heart and improving exercise capacity.
Sildenafil is usually taken orally, in pill form. The dosage and frequency of use depend on the condition being treated and your response to the medication. For ED, it is typically taken as needed before sexual activity, while for PAH, it may be taken regularly as prescribed.
Follow the prescribed dosage and instructions carefully. Do not take more sildenafil than recommended, and do not stop taking it without consulting your healthcare provider.
The time it takes to experience the effects of sildenafil can vary. For ED, you may notice improvements in erectile function shortly after taking the medication, typically within 30 minutes to an hour. For PAH, improvements in symptoms such as shortness of breath may take longer. It’s important to continue taking sildenafil as prescribed for best results.
While sildenafil is primarily used for ED and PAH, healthcare providers may sometimes prescribe it off-label for other conditions such as Raynaud's phenomenon or altitude sickness.
Discuss any alternative uses of sildenafil with your healthcare provider.
Sildenafil is available in the following dosage forms:
Generic versions of sildenafil are available under various brand names.
Sildenafil is a prescription medication. You will need a valid prescription from a licensed healthcare provider to obtain this medication.
The use of sildenafil, whether for erectile dysfunction (ED) or pulmonary arterial hypertension (PAH), can lead to various side effects in some individuals.
Common mild side effects of sildenafil use include:
More severe side effects of sildenafil use can include:
If you experience any severe side effects while using sildenafil, especially those that indicate a serious reaction, seek medical attention promptly.
Before using sildenafil, inform your healthcare provider about any existing medical conditions, allergies, or medications you are currently taking. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with sildenafil.
Tell your provider if you are taking the following medications or supplements:
Additionally, mention any medical conditions you have, such as:
You should also tell your provider if you smoke, or use illicit drugs containing nitrates.
If you are pregnant, planning to become pregnant, or breastfeeding, discuss the potential risks and benefits of using sildenafil with your healthcare provider.
Take sildenafil exactly as prescribed by your healthcare provider. Do not increase or decrease the dosage without consulting them.
Do not take sildenafil with alcohol or grapefruit juice, as they may interact and increase the risk of side effects.
If you experience sudden vision or hearing changes while taking sildenafil, stop using it and seek medical attention.
In case of a sildenafil overdose, seek medical attention immediately. Symptoms of overdose may include severe dizziness, fainting, or priapism (prolonged erection). If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.
Sildenafil is available in the following forms:
The typical starting dose of sildenafil varies depending on the condition being treated, the severity of symptoms, and individual patient factors. It is important to follow your healthcare provider's instructions regarding dosage and administration.
For erectile dysfunction, the typical starting doses may be:
Your healthcare provider will determine the most appropriate dose based on your medical history, current medications, and response to treatment.
Sildenafil should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage or need adjustments, contact your healthcare provider for guidance. If you need immediate medical advice or assistance, consider scheduling an online doctor appointment through a platform like Sesame.
For ED:
For PAH:
Continue taking sildenafil as prescribed, even if you start feeling better. Do not stop taking it without consulting your healthcare provider.
Store sildenafil tablets at room temperature, away from moisture, heat, and light. Keep the medication in its original packaging and out of reach of children.