June 13, 2023 Dr. James D Jablonski

Know About PDE5 Inhibitor Drugs

What are PDE5 inhibitors?

PDE5 Inhibitors are consumed as an oral drug and they are mainly functional to treat erectile dysfunction in men. PDE5 or Phosphodiesterase type 5 is a type of drug that may disrupt blood flow and how the cells communicate in the human body. While the enzymes of the PDE superfamily can be divided into 11 different mammalian families, PDE5 is commonly responsible for sexual disorders in men.

PDE5 inhibitors control the effect of these enzymes in the walls of blood vessels and manage other helpful molecules to keep the blood flow normally in the body. The amount of Phosphodiesterase type 5 can increase due to some food intakes and supplements, like horny goat weed, black ginger, and Tribulus Terrestris. This satisfies why choosing the right type of inhibitor is a crucial step. 

Types of PDE5 Inhibitors

There are some FDA-approved and non-approved PDE5 inhibitors that are available in the market. Here are the FDA-approved ones as follows:

Sildenafil (Viagra)

Sildenafil is sold under its brand name Viagra, which is quite common as a drug. It can be taken regularly in different dosages from 25 mg to 100 mg. Daily one intake would last from 4 to 12 hours. Sildenafil takes at least an hour to start reacting in the body.

This is the oldest PDE5 inhibitor to be approved by FDA back in 1993. That’s why it is much familiar in the market.

Tadalafil (Cialis)

 Tadalafil is mainly available in the market under the brand name Cialis, but can also be found under the brand name Adcirca. This is another PDE5 inhibitor that is used to treat ED (erectile dysfunction) in men. Apart from that, it is also used to treat benign prostate hyperplasia (BPH).

It can start reacting in the body after twenty minutes to half an hour of consumption and lasts from 24 to 36 hours, which is the longest. Also, the dosage is minimum compared to other PDE5 inhibitors. A daily dosage of 2.5 to 20 mg is enough for Tadalafil to work.

Vardenafil (Levitra)

Both Vardenafil and Tadalafil are approved by FDA in 2003. Vardenafil is sold under Levitra or Staxyn brand. This medicine can be taken 5 to 20 mg per day and it lasts up to 5-7 hours usually. However, in some cases, the effect lasts up to 12 hours.

Vardenafil starts the reaction in the least time compared to other inhibitors. It takes effect with 10 minutes of consumption. 

Avanafil (Stendra)

Avanafil Medicine is the most recently FDA-approved PDE5 inhibitor that treats erectile dysfunction in men. This drug is sold under the brand name Stendra. The daily dosage usually lies between 50 to 200 mg per day. It takes effect in 30 to 45 minutes and lasts for about 5 hours.

According to a study by PubMed in 2016, Avanafil is lesser side effects than the other PDE5 inhibitors available in the market.

There are some PDE5 inhibitors available in the market that are not yet approved by FDA. Still, they are commercially popular. Some of these drugs include Lodenafil, Udenafil, and Mirodenafi. It is better not to consume them as there may be some severe side effects related to them. 

How do PDE5 Inhibitors Work?

Achieving a satisfying erection is a complex physiological process. When a man is sexually aroused, his parasympathetic nervous system becomes activated. This system releases nitric oxide, which further releases another molecule called cGMP or Cyclic guanosine monophosphate. This particular molecule helps the blood vessels in the male genital area to circulate blood smoothly by 20 to 40 times.

However, PDE5 breaks the cyclic GMP, and the required blood flow is never reached. PDE5 inhibitors have a similar structure to cyclic GMP and they block this breakdown. As a result, the release of NO increases followed by a better erection.

An important takeaway here is, PDE5 inhibitors only work when the man is sexually aroused. These drugs are not responsible to make a man sexually active.

Apart from treating ED, PDE5 inhibitors can also help in some other aspects. For example, it helps control the blood flow to the arteries in the lungs, lifts blood flow to the lungs, and reduce blood pressure. Moreover, these drugs are also effective in treating cognitive disorders like dementia.

Risks and Side Effects of PDE5 Inhibitors:

Consuming PDE5 inhibitors can also result correctly when all the risk factors are known and required precautions are taken. Here are some of the major side effects of these drugs that need to be avoided.

• People who consume nitrate medications should avoid having any PDE5 inhibitors as both medicines may interact with each other. Nitrate medicines like Nitrostat, Dilatrate-SR, Isordil, Imdur, Monoket, and Poppers taken for heart issues interact with PDE5 inhibitors.
• Someone who had a stroke in the last 6 months or has a history of f heart attack, or severe arrhythmia needs to avoid any PDE5 inhibitor consumption.
• Those who currently using alpha-blockers should not intake these drugs. The same goes for someone having hypertension or angina.
• Some common side effects of PDE5 inhibitors include dizziness, flushing, headaches, disturbed vision, muscle, and back pain, etc.
• Some rare side effects of PDE5 inhibitors include sudden loss of hearing, priapism (prolonged and painful erection), and blurred vision.

Conclusion

This article includes everything about PDE5 inhibitors and how they work to penetrate erectile dysfunction in men. As each drug has a different composition and they come with several potential side effects, the drugs should not be consumed without a doctor’s suggestion. The same is applicable to the dosage and frequency of the medicine. Following these precautions would result in a better experience with the intake for sure.