The Ultimate Guide to Understanding the Side Effects of Sildenafil
Erectile Dysfunction
April 1, 2024

The Ultimate Guide to Understanding the Side Effects of Sildenafil

Sildenafil is a prescribed drug that is well-known for its ability to treat erectile dysfunction (ED). Although it is effective in enhancing sexual function, users should be mindful of its possible adverse effects.

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Recap: What is Sildenafil?

Sildenafil, the generic form of Viagra, is a type of medication that helps with erectile dysfunction (ED) and sometimes enlarged prostate (BPH). It works by blocking PDE5 and has the benefit of working faster than other similar drugs, allowing for more flexibility when planning sexual activity.

Side Effects of Sildenafil

Sildenafil can cause a variety of side effects, which can vary in severity depending on the dosage, individual health, and other factors.

Common Side Effects

  1. Headaches are the most common occurrence, but they can usually be controlled with over-the-counter pain relievers
  2. Nasal congestion is another common issue, but it can be managed
  3. Flushing caused by increased blood flow, resulting in a red face
  4. Indigestion after taking the medication
  5. Dizziness, make sure to stay hydrated and sit or lie down to help alleviate the symptoms

Side Effects by Dosage

Two tablets of Sildenafil 100mg

Sildenafil 25 mg and 50 mg: Commonly recommended for individuals who want lower doses or have certain health concerns, these doses are linked to less severe side effects.

Sildenafil 100 mg: Frequently suggested for people who favour weaker doses or have particular health issues, these doses are connected to gentler side effects.
Specific Side Effects and Concerns

Blood Pressure Variations

Like Cialis, Sildenafil reduces blood pressure by relaxing muscles in blood vessel walls, making them wider and enhancing blood flow. This widening of blood vessels leads to lower blood pressure.

Vision and Hearing

Sometimes, people who take Sildenafil may have trouble seeing clearly or suddenly lose their vision, but this is not common. There have been a few cases where users have also noticed a decrease in their ability to hear after using Sildenafil. It's important to quickly seek medical advice if these side effects happen.

Liver and Kidney Effects

Men with existing liver or kidney issues need to be cautious when using Sildenafil because it is processed by these organs.

Psychological and Neurological Effects

As mentioned earlier, Sildenafil may lead to headaches and dizziness, affecting your focus and enjoyment of daily tasks. These reactions are usually the body's first reaction to the medication.

Long-term Use 

Cardiovascular Health 

Those who use Sildenafil for a long time should monitor their heart health regularly, especially if they have heart conditions or are at risk of heart disease.

Adjusting for Efficacy and Dependence

Over time, the way the body reacts to Sildenafil may vary, which may necessitate changes in the dosage. It is also crucial to be cautious about relying too much on Sildenafil for sexual confidence and to seek help from a healthcare provider to address any psychological dependence.

Mixing with Alcohol

Alcohol can worsen specific side effects, particularly those linked to blood pressure. It is recommended to restrict alcohol consumption to decrease the chances of experiencing negative reactions such as feeling lightheaded or passing out.

Use with Other Medications

It's important to know how Sildenafil interacts with other medications you're taking to make sure it works well and keeps you safe.

Nitrates and Alpha-Blockers: Medications for heart conditions and high blood pressure can lower blood pressure significantly when combined with Sildenafil. This may result in dizziness, fainting, or other heart-related problems. Inform your healthcare provider about these medications before using Sildenafil.

Other ED Medications: It is not advised to mix Sildenafil with other ED medications like Cialis or Avanafil because it can lead to serious side effects like low blood pressure or prolonged erections that may cause permanent harm to the penis.

PE Medications: For those also dealing with premature ejaculation (PE), combining Sildenafil with medications like Dapoxetine (a treatment specifically for PE) is possible under medical guidance. Dapoxetine boosts serotonin levels to help delay ejaculation. Combining Sildenafil and Dapoxetine can treat both ED and PE, but it's important to consult a healthcare provider for proper supervision and to avoid potential side effects.

Effects on Specific Groups

The Elderly

As you get older, you may observe that Sildenafil remains in the body for a longer time, causing the effects to last longer and possibly increasing the side effects. This happens because the metabolic rate naturally decreases with age. 

Healthcare professionals usually begin with the smallest dose possible to assess how well it works and how well it is tolerated, making adjustments as needed to achieve the optimal balance between effectiveness and side effects.

Men with Pre-existing Conditions

Sildenafil can cause stronger side effects in people with pre-existing conditions, particularly those that affect the liver, kidneys, or heart.

For individuals with liver or kidney problems, Sildenafil may not be metabolised as effectively, resulting in higher levels in the bloodstream and a greater chance of experiencing side effects.

Patients with heart conditions need to be careful because the increased blood flow and physical exertion during sexual activity can put strain on the heart. It is important for these individuals to undergo a thorough evaluation by a healthcare professional to determine if Sildenafil is a safe choice for them.

Managing and Mitigating Side Effects

Making changes to your lifestyle and diet can have a big impact on reducing the side effects of Sildenafil. For instance, it's a good idea to avoid eating heavy meals and drinking alcohol before taking Sildenafil to minimise indigestion and flushing. 

Drinking plenty of water can help alleviate headaches, and it's important to avoid activities that could make dizziness worse until you know how Sildenafil affects you. 

It's crucial to have open communication with your healthcare providers so they can provide strategies that are tailored to your lifestyle and specific side effects, ensuring that Sildenafil continues to be effective and well-tolerated.

Uncommon and Rare Side Effects

It is important to seek immediate medical help if you experience severe allergic reactions to Sildenafil, such as trouble breathing or swelling of the face, lips, tongue, or throat. 

If you have symptoms of priapism, which is a prolonged and painful erection lasting more than 4 hours, it is also necessary to seek urgent care to avoid permanent damage. While these side effects are uncommon, it is crucial to be aware of them and know when to seek assistance to use Sildenafil safely.

Risks of Counterfeit Sildenafil

Buying Sildenafil from trustworthy sources is crucial to avoid fake pills that could be dangerous. Fake products might have the wrong amount of medicine, incorrect components, or harmful additions, which can be harmful to your health.

Make sure to purchase Sildenafil from authorised pharmacies or verified online sellers. If you have any doubts about the legitimacy of your medication, it's important to seek advice from a healthcare professional.

Comparison with Other ED Medications

Sildenafil vs. Tadalafil

2 pills of Tadalafil 20mg

Onset and Duration

Sildenafil usually starts working in 30- 60 minutes and can last for 4-5 hours, which is great for people who like to plan their sexual activity in advance.

Tadalafil takes longer to start working, around 2 hours, but stays effective for up to 36 hours (depending on the dose), providing more freedom and spontaneity.

Side Effect Profiles

Sildenafil and Tadalafil have similar side effects such as headaches, flushing, and indigestion. But Tadalafil may lead to back pain and muscle aches, which are not as common with Sildenafil.


Sildenafil is suited for those who prefer precise timing of sexual activity.

Tadalafil is better for individuals seeking a longer window of effectiveness without the need for precise timing.

Health Considerations

Sildenafil and Tadalafil both require caution in individuals with cardiovascular conditions but may be chosen based on how their duration of action aligns with individual health needs.

A healthcare provider's input is essential to navigate potential interactions with other medications and pre-existing conditions.

Sildenafil vs. Spedra (Avanafil)

Onset and Duration

Spedra is famous for its rapid action, starting to work in just 15-30 minutes after consumption, and its effects can last for approximately 4-6 hours.

Sildenafil takes effect in 30 to 60 minutes and has a similar duration of action, although it may not be as fast as Spedra for certain people.

Side Effect Profiles

Spedra has similar side effects to Sildenafil, but it is often said to cause fewer side effects because it acts more selectively in the body.

Both can cause headaches, flushing, and nasal congestion, but Spedra might have fewer side effects for some people.


Spedra is a great choice if you want fast results and fewer side effects, making it perfect for unexpected events.

Sildenafil remains a reliable choice for many, with its well-established profile and effectiveness.

Health Considerations

Similar to Sildenafil, Spedra needs to be used cautiously in people with specific health conditions, particularly those related to heart health.

It's important to talk to a doctor to decide on the best choice between the quick effects of Spedra and the proven effectiveness of Sildenafil.

If you're having trouble with erectile dysfunction, it's important to seek advice from a medical professional. At noah™, our doctors are highly skilled and experienced in identifying the underlying causes of ED.

They will offer you expert recommendations on the best treatment options that are specifically tailored to your individual needs. If required, they can also prescribe the appropriate medication to support you in overcoming ED.

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Written by our Editorial Team
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