PDE5 Inhibitor: What Does It Mean?

PDE5 inhibitors are a group of medicines initially developed to treat cardiovascular issues. But today they are widely used for erectile dysfunction in men.

In this blog, we will explain what PDE5 inhibitors are, how they work, what their adverse effects are, and the effective and safest inhibitors available on the market.

What Are PDE5 Inhibitors?

PDE5 inhibitors are a class of medications that work by relaxing blood vessels and improving blood flow to certain parts of the body. They do it by hindering the activity of an enzyme called phosphodiesterase type 5 (PDE5) [1].

What Are The Uses Of PDE5 Inhibitors?

The use of PDE5 inhibitors is approved to treat the following conditions:

Erectile Dysfunction:

Erectile dysfunction (ED) or impotence is a common sexual dysfunction in men. It is a condition characterized by the inability or difficulty to achieve or maintain an erection.

Currently, PDE5 inhibitors are used by millions of men to address ED in the United States and worldwide because of their effectiveness, quick onset of action, longer-lasting effects, and minimal side effects.

Pulmonary Arterial Hypertension:

Pulmonary Arterial Hypertension is a type of high blood pressure affecting the arteries in the lungs [2]. Some of the symptoms of PAH include chest pain, shortness of breath, a fast heartbeat, and tiredness. It can also affect the blood flow throughout the body.

Benign Prostatic Hyperplasia (BPH):

BPH, or Benign Prostatic Hyperplasia, occurs when the prostate becomes enlarged. It causes difficulty while urinating because of the enlargement of the prostate gland.

In the United States, 70% of males in their 60s and 80% of men in their 70s or older are affected by this condition.

How do PDE5 Inhibitors Work?

For Erectile dysfunction 

When a man is sexually aroused, his body releases nitric oxide (NO). This helps in blood vessel relaxation, making it easier for proper blood flow to the penis.

Nitric oxide helps produce another substance known as cyclic guanosine monophosphate. The cGMP acts as a helper that lets blood vessels open up, allowing more blood to fill the penis, which results in a firm erection.

For Pulmonary Hypertension

For people suffering from Pulmonary Hypertension, the PDE5 inhibitors can help by:

• Increasing the blood flow in the lungs.
• Controlling the blood flow in the arteries of the lungs.
• Lowering blood pressure.

For Benign Prostatic Hyperplasia, PDE5 inhibitors work by relaxing the smooth muscles in the bladder and prostate gland.

Which Are The Most Effective PDE5 Inhibitors?

Some of the most commonly used PDE5 inhibitors are listed below. These are the products also available at Pharmabridge International at an affordable price:

Sildenafil Citrate:

Sildenafil Citrate is a well-known medication available in the market. Generic Viagra, which contains the active ingredient Sildenafil, was the first PDE5 inhibitor available to the public to treat Erectile dysfunction (ED). This ED medication is taken 30 minutes before sexual activity and its effects last for up to 4-6 hours.

Tadalafil:

Tadalafil or Generic Cialis is also a prescription medication commonly used to treat erectile dysfunction. It belongs to a class of drugs known as PDE5 inhibitors, which work by improving blood flow to the abdomen. When a person is sexually stimulated, Tadalafil helps relax the blood vessels in the penis. This allows increased blood flow, making it easier to achieve and maintain an erection. It is important to note that the medicine works only in the presence of sexual stimulation; it does not cause an automatic erection.
One of the key features of Tadalafil is its long duration of action. A single dose can remain effective for up to 36 hours, which is why it is often referred to as the weekend pill.

Vardenafil:

Vardenafil is a prescription medication used in the treatment of erectile dysfunction. It is part of the PDE5 inhibitor group, which supports improved blood flow by helping blood vessels relax during sexual stimulation.

The effects of Vardenafil generally last for several hours, offering a suitable window for planned sexual activity. It should be taken as directed by a healthcare professional, usually 30 minutes before intercourse, and not more than once per day.

The other generic options for Vardenafil tablets include Vilitra and Vitara. Where higher doses like Vitara V 60mg tablets are often prescribed by doctors for managing severe cases of ED.

Who Can Benefit From PDE5 Inhibitors?

The following are the people who benefit from PDE5 Inhibitors:

• People suffering from Erectile dysfunction: These medications help in achieving and maintaining an erection by increasing the blood flow to the penis.
• People suffering from Pulmonary Arterial Hypertension: The PDE5 inhibitors improve exercise ability and help in reducing the symptoms of PAH by relaxing blood vessels in the lungs.
• People suffering from heart disease: Several studies have mentioned that PDE5 inhibitors have potential cardiovascular benefits.

Natural PDE5 Inhibitors

In addition to medications, there are several natural PDE5 inhibitors, such as [3] –

L-arginine:

It is a type of amino acid available in many foods. A 2020 study by Luigi Gallo et al. suggests that L-arginine, when combined with Tadalafil, increases the effectiveness of the drug.

Black Ginger:

Black ginger, also known as kaempferia parviflora, has a PDE5-inhibiting effect. A small study from 2018 of 4 participants found that ethanol extract from the black ginger plant may improve erectile function. However, more research is necessary to determine the effectiveness and safety of this plant.

Tongkat Ali:

Tongkat ali, also known as Eurycoma Longifolia, is a native plant in Indonesia and Malaysia. There are some evidence where it was found that Tongkat Ali increases testosterone levels and arousal, which may help improve ED.

Yohimbine (Yocon):

It is a compound present in a tree that is native to central and western Africa.  There are many traditional medicines available that use the bark to increase sexual arousal and performance. However, the National Center for Complementary and Integrative Health states that there is not enough evidence to state that Yohimbine is effective in treating ED. However, it is important to note that the use of yohimbine has an association with heart attacks and seizures. So it should be used with caution.

Side Effects of PDE5 Inhibitors

PDE5 can also cause side effects and interact with other drugs. However, they are well-tolerated medicines if used as directed. Some of the side effects are manageable, although some might require immediate medical attention and treatment.

Some of the common side effects of PDE5 inhibitors include:

• Facial flushing.
• Nasal congestion.
• Headaches.
• Cold-like symptoms.
• Dyspepsia.
• Back or muscle pain.

Some serious side effects that require immediate medical attention are –

• Priapism (prolonged and painful erection).
• Hearing issues
• Loss of vision

The severity of the side effects can increase depending on the dose. If taken in excessive amounts, PDE5 inhibitors can cause a rapid drop in blood pressure and fainting.

Conclusion

PDE5 inhibitors are widely used medications that play an important role in improving blood flow in the body. While they are most commonly known for treating erectile dysfunction, they are also used in conditions like pulmonary arterial hypertension and benign prostatic hyperplasia. By supporting the natural process of blood vessel relaxation, these medicines help manage symptoms effectively when used as prescribed.

Common options such as Sildenafil, Tadalafil, and Vardenafil differ in how quickly they work and how long their effects last. Although generally well-tolerated, they can cause side effects and may not be suitable for everyone, especially when taken with certain medications or in high doses.