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, also referred to as enlarged prostate, occurs when the prostate becomes large in size.  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 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 hours.

Tadalafil:

It is a PDE5 inhibitor that is available both as a generic and brand drug version. The medical use of Tadalafil is approved by several regulatory bodies, including the FDA, MHRA, and TGA. It has a longer duration of action compared to other medicines of the same class, which is up to 36 hours.

Vardenafil:

It is an FDA, MHRA, and TGA-approved PDE5 inhibitor that is available under various generic names such as Vilitra tablets and Vitara. The effects of this medication last for about four to eight hours.

Who Can Benefit From PDE5 Inhibitors?

The following are the people who benefit from PDE5 Inhibitors:

• People suffering from Erectile dysfunction: The 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 slight PDE5-inhibiting effect.

A small study of 2018 of 4 participants found that ethanol extract from the black ginger plant may improve erection 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 the symptoms of Erectile dysfunction. It has also been found that yohimbine has an association with heart attacks and seizures. Several countries have banned yohimbine due to safety concerns.

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

However, 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 medicines for treating erectile dysfunction, pulmonary arterial hypertension, and benign prostatic hyperplasia.  These medications are chosen by millions of people because of their high rates of user satisfaction. There are also certain natural PDE5 inhibitors, such as horny goat weed, tongkat ali, L-arginine, and black ginger.