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Understanding Sildenafil: Mechanism and Benefits

Erectile Dysfunction (ED) is a common issue that affects millions of men worldwide. It’s often characterized by the inability to achieve or maintain an erection. Despite its prevalence, it’s a subject that many find difficult to discuss, even with their healthcare providers. 

However, it’s essential to know that ED is a treatable condition, and various options are available for managing its symptoms. One such option that has gained significant recognition in the medical field is a medication called Sildenafil.

What is Sildenafil?

Sildenafil is a medication primarily used to treat erectile dysfunction (ED). It belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. The medication was first developed by Pfizer and sold under the brand name Viagra. 

However, generic versions of the drug are now widely available. The advent of Sildenafil has revolutionized the treatment of ED, providing a direct, effective solution where previous options were limited or invasive.

Sildenafil is typically administered orally, with three different strengths: 25mg, 50mg, and 100mg. Your healthcare provider will determine the appropriate dosage based on several factors, including your overall health, the severity of your ED, and your response to the medication.

How Sildenafil Works in Treating Erectile Dysfunction

The way Sildenafil works to treat ED is both complex and fascinating. It relaxes the muscles of blood vessels, increasing blood flow to the penis.  The primary cause of an erection is an increase in blood flow to the penile tissues; therefore, Sildenafil helps to achieve and sustain erections by improving this process. [1]

However, it’s important to note that Sildenafil doesn’t produce an erection alone. Sexual stimulation is necessary to activate the release of nitric oxide, the chemical that Sildenafil acts on. Once activated, Sildenafil inhibits the PDE5 enzyme responsible for cyclic guanosine monophosphate (cGMP) breakdown. By blocking the PDE5 enzyme, Sildenafil ensures that cGMP levels remain high, enabling smooth muscle relaxation and promoting increased blood flow.

Potential Side Effects of Sildenafil

Like any medication, Sildenafil can have potential side effects. While most men do not experience severe side effects, knowing what these could be is still important. Common side effects include headaches, flushing, upset stomach, abnormal vision, stuffy or runny nose, back pain, muscle pain, and nausea. [2]

In rare cases, Sildenafil can cause more serious side effects, such as an erection that won’t go away (priapism), [3]  sudden vision loss in one or both eyes, or sudden hearing decrease or loss. If you experience any of these, you should seek medical attention immediately.

Precautions to Take While Using Sildenafil

When using Sildenafil, certain precautions must be taken to ensure safe use. Discussing your medical history with your healthcare provider before starting this medication is essential. 

Tell your doctor or pharmacist of your medical history before taking this medication, especially of: heart problems (such as heart attack or life-threatening irregular heartbeat in the past six months, chest pain/angina, heart failure), stroke in the past six months, kidney disease, liver disease, high or low blood pressure, dehydration, penis conditions (such as angulation, fibrosis/scarring, Peyronie’s disease), history of painful/prolonged erections (priapism).

Sildenafil can interact with other medications, particularly nitrates used for heart disease, and can lower blood pressure to dangerous levels if combined.

It’s also important to avoid excessive alcohol consumption while taking Sildenafil, as this can increase the likelihood of side effects. Additionally, Sildenafil should not be used recreationally or without a prescription, as misuse can lead to unwanted health complications.

Sildenafil Dosage

The dosage of Sildenafil depends on the individual’s overall health, age, and response to the medication. The recommended starting dose for most men is 50mg, taken approximately one hour before sexual activity. However, the dose may be increased to a maximum recommended dose of 100mg or decreased to 25mg, depending on the effectiveness and tolerability.

It’s crucial to follow your healthcare provider’s instructions when taking Sildenafil. The medication should not be taken more than once a day, and it’s important to take it only when needed, roughly an hour before sexual activity.

To manage PAH (Pulmonary Arterial Hypertension), Sildenafil is typically administered in three daily doses, spaced 4 to 6 hours apart. This dosing regimen aims to improve exercise capacity and delay clinical worsening associated with the condition.

Special considerations apply to patients with severe renal impairment, hepatic dysfunction, and those aged 65 years and above. Given that these individuals typically exhibit higher plasma levels of Sildenafil, it is recommended to commence treatment at a lower dose of 25 mg.

How to Use Sildenafil

Sildenafil is typically taken as needed, about one hour before sexual activity. However, it can be taken anywhere from 30 minutes to four hours before sexual activity. It’s not recommended to take Sildenafil more than once a day.

The medication can be taken with or without food, but keep in mind that if it’s taken with a high-fat meal, it may take longer for the medication to start working.

Interaction With Other Medications

As mentioned earlier, Sildenafil can interact with other medications. This is why informing your doctor about all the drugs you’re currently taking, including non-prescription, prescription, and herbal products is crucial.

Particularly, drugs that can interact with Sildenafil include nitrates (used for chest pain), drugs used to treat high blood pressure or a prostate disorder, certain antifungal medicines, and certain HIV medicines.

If you’re uncertain about potential interactions, it’s always best to consult your healthcare provider.

Comparing Sildenafil to Other Erectile Dysfunction Treatments

Sildenafil is one of several treatments available for ED. Other medications include tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra), all of which belong to the same class of drugs as Sildenafil – PDE5 inhibitors. These drugs work similarly, but they differ in terms of how long their effect lasts and their side effect profiles.

While Sildenafil is effective for most men, it might not work for everyone. In such cases, other treatment options, such as vacuum erection devices, penile implants, or injections, may be explored. It’s important to discuss all available options with your healthcare provider to determine the best treatment approach for you.

Conclusion: Sildenafil – A Reliable Solution for Erectile Dysfunction Treatment

In conclusion, Sildenafil has revolutionized the treatment of ED, offering an effective, convenient, and well-tolerated solution for many men dealing with this condition. It’s important to approach ED openly and proactively, seeking medical advice if you’re experiencing symptoms. 

Remember, ED is a common and treatable condition, and medications like Sildenafil can help restore sexual health and confidence.

Remember, while Sildenafil is an effective solution for ED, it’s crucial to use it responsibly and under the guidance of a healthcare provider. Always follow your provider’s instructions when taking this medication and communicate any concerns or side effects you may experience. 

Together, you and your healthcare provider can find the best approach to managing your ED and improving your overall quality of life.


1. 1.Goldstein I, Burnett AL, Rosen RC, Park PW, Stecher VJ. The Serendipitous Story of Sildenafil: An Unexpected Oral Therapy for Erectile Dysfunction. Sex Med Rev. 2019 Jan;7(1):115-128.

2. 2.Moreira SG Jr, Brannigan RE, Spitz A, Orejuela FJ, Lipshultz LI, Kim ED. Side-effect profile of sildenafil citrate (Viagra) in clinical practice. Urology. 2000 Sep 1;56(3):474-6. doi: 10.1016/s0090-4295(00)00649-x. PMID: 10962318.

3. 3.Ekeke ON, Omunakwe HE, Eke N. Management of priapism in adult men. Int Surg. 2015 Mar;100(3):552-7

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