Understanding How Erectile Dysfunction Drugs Work 


By Chinedu Akpa. Freelance Health Writer and DLHA Volunteer. Medical review and editorial support provided by The DLHA Team.

ED drugs poured on a table

ED drugs poured on a table.




  • Erectile dysfunction is both a medical condition and a psychosocial problem.
  • Understanding the underlying cause of erectile dysfunction is the hallmark of an effective treatment plan.
  • PDE5i is the mainstay treatment medication but side effects are causing people to search for alternatives. 
  • African traditional medicines may have a lot to offer when it comes to erectile dysfunction treatment.





Nothing makes an African man feel more like a king than to have a satisfying sexual encounter with his partner. It is a source of pride that is often discussed at bars, viewing centers, and even at work. 


Anecdotally, in Africa, the amount of time a man lasts in bed is sometimes equated in patriarchic terms with his ability to solve a woman’s sexual desires. This expectation puts pressure on men, and in order to meet peer and personal expectations, they may go to extreme lengths to solve any perceived sexual performance problems. These may include performing rituals and using charms. 


This pressure is understandable because no man wants to be seen as an impotent, and with the porn industry’s glamorization of sex, it becomes even scarier. 


Erectile dysfunction (ED) is the cog in the wheel of many men’s sexual lives. It dampens their confidence, causes anxiety, and may cause social phobia in some. 


This article explains in simple terms how erectile dysfunction drugs work and how to best manage the condition.



What is ED?


Erectile dysfunction is the continuous inability to achieve or maintain penile erection enough for sexual satisfaction [1]. In 1995, the global estimate of ED was 152 million men, but it is expected to rise to 322 million by 2025, a more than 100% increase. The increase is expected to be more pronounced in developing continents such as Africa. [2]


ED is more commonly an indicator of an underlying illness than a standalone illness. ED typically occurs between the ages of 40 and 70, but a growing number of younger men are reporting to healthcare providers with it. When questioned, many of them (especially the younger ones in Nigeria for example) admit to using a combination of herbs, tramadol, and other mixtures to help them last longer before experiencing ED. It should be noted that the use of this cocktail was not motivated by ED, but by peer pressure and a desire to demonstrate their macho power to their female sexual partners.  


How Does Erection Occur? 


An erection involves a complex interaction of hormones, nerves, muscles, and blood vessels. It begins from the brain, a rested mind (psychological factor) is more likely to get an erection than a restless one.


There are three chambers that surround the penis. When the brain senses an urge, it sends signals to the nerves of the penis, then the artery swings into action by carrying blood to these chambers causing a filling of the chambers. This in turn gives rise to the hardening of the penis. [3] Physical stimulation, thoughts, smell, pictures or videos can also cause arousal which can set this whole process in motion. 


Any disease or condition that reduces or blocks blood flow to the three chambers surrounding the penis will result in erectile dysfunction.



Is ED curable?


Understanding the underlying cause of ED is important to answering this question. This would also help in appreciating that not all people with ED require medication.


As previously stated, the pathway of an erection includes blood vessels, nerves, hormones, and muscles. Anything that obstructs this pathway, such as nerve diseases like multiple sclerosis, can cause erectile dysfunction, as can high blood pressure, type 2 diabetes, chronic kidney disease, atherosclerosis, heart disease, and Peyronie's disease. Our mental and emotional states also play a role. Coupled with all these factors is the use of drugs. For example, antipsychotic drugs like risperidone have been found to cause ED.


ED can be cured if the underlying cause is identified and it is curable if well managed. When the underlying cause is identified but not curable, as in multiple sclerosis for example, ED can last for the duration of the disease.


Cognitive behavioral therapy has been shown to be effective in restoring mental health, in which case drugs may be unnecessary.



What Are Erectile Dysfunction Drugs?


Before beginning treatment for ED, it is critical to determine the underlying cause. Failure to address this issue may render the use of any drug completely or partially ineffective. 


The following are the classes of medication that are used to treat ED.

  • Phosphodiesterase inhibitors (PDE5i): Examples are sildenafil, tadalafil, vardenafil and avanafil.
  • Androgens: These medications are usually presented in oral, injectable, transdermal, and gel form. They are the synthetic form of testosterone.


  • Vasodilators: Examples are alprostadil, phentolamine.


PDE5i is the most common class of ED medication on the African continent, with generic and branded versions of sildenafil and tadalafil  being readily available on pharmacy shelves. 


1. Phosphodiesterase Inhibitors 


PDE5i was discovered by accident. It was created as a result of side effects (penile erection) noted while studying its use in hypertension and angina. It is typically the first line of treatment for people suffering from ED.


Studies in over 250,000 men found that none of the PDE5i drugs outperformed the others. [4] While there is no superiority in how these drugs work, some are short-acting and others are long-acting. Tadalafil has the longest duration of action (23-36 hours), whereas Vardenafil has the shortest (5-12 hours). 


Tadalafil's long acting duration allows it to be taken every other day regardless of when sexual activity occurs. In fact, it is best to take these medications only as needed.


PDE5i is usually started at the lowest possible dose and increased as needed. It may be taken with or without food. Common side effects include flushing, headaches, indigestion, a stuffy or runny nose, back pain, and muscle aches. 


How PDE5i Drugs Work?


Cyclic guanosine monophosphate (cGMP) is an enzyme that widens blood vessels. PDE5 degrades this enzyme and inhibits its action. Tadalafil and other PDE5 inhibitors work by preventing the breakdown of cGMP, thereby extending their blood vessel widening activity to the penile blood vessel. [5] 


When Not To Use PDE5i Medications


There are some medication and disease conditions that preclude one from using PDE5i medications. Below are some of them.


Patients taking nitrates or nitroglycerin for angina should avoid combining them with PDE5i due to their additive hypotensive effect. [6] It is recommended to wait 1 to 2 days after the last dose of nitrate before taking PDE5i. Alpha blockers, such as doxazosin, should not be used concurrently because they both lower blood pressure.



The following disease conditions have been fingered to be contraindicated in PDE5i use:

  • Low blood pressure
  • Heart or liver disease
  • Peyronie’s disease
  • Stroke
  • PDE5i allergy



2. Androgens


The function of androgen in erectile dysfunction remains a subject of debate among researchers. The reason for the debate is that men with low testosterone who were given sildenafil alone did not achieve an erection until testosterone shots were administered. [7] However, some researchers argue that testosterone is only useful for libido, not erections. [8]


New research has shown however, that a lack of testosterone can affect the tissues of the penis, resulting in poor erection. [8] As a result, it is now widely accepted that androgens play an important role in both libido and penile erection. So, testosterone administration can help people with erectile dysfunction caused by hypogonadism. 


3. Vasodilators


Alprostadil and Phentolamine are potent vasodilators (blood vessel dilators). They aren't popular in the African continent. Moreso, they are classified as second line treatment options. 

  • Alprostadil: It is an analogue of a chemical called prostaglandin. It is the site that this chemical binds that determines its vasodilation activity. It can be applied by injection into the corpus cavernosum of the penis (intracavernously). Side effects include headache, dizziness, hypotension, syncope, priapism, and urethral strictures.
  • Phentolamine: It blocks the effect of adrenergic blood vessels constricting chemicals like epinephrine and norepinephrine to open up the blood vessels for more blood flow. It usually comes as an injection. Side effects include hypotension, diarrhea, cardiac dysrhythmia, and myocardial infarction.  



Common Supplements Used To Manage ED


The banging headache that comes with the use of PDE5i is a major concern to many. Something that is meant to help have pleasure shouldn't leave a bitter taste in the mouth afterwards. This complaint has given rise to the increasing need to find alternatives to the PDE5i. 


And since PDE5i are first line drugs of choice, these alternatives are being sought for in plants and herbs. In Africa, this shouldn't be surprising as the continent is blessed with many medicinal herbs and plants. 


Yohimbine, Eriosema Kraussianum (uBangalala), and Maca root are some common supplements used on the African continent to help with ED.




It is a plant native to Africa and has been used for years for its sexual aiding abilities. Analysis of different studies done on Yohimbine discovered that it is effective in managing ED only when combined with other supplements. [9]


Eriosema Kraussianum


This is a plant native to South Africa, it has been used by the Zulu ethnic group of the country to treat ED for centuries. Decoctions of the root of this plant is widely used in South Africa especially among the Zulus to treat ED. Scientific evidence to this effect is still scanty. [10]


Maca Root


Maca has its roots from Southern America, and it has been used for male fertility and ED for a long period. But available studies and evidence show that there is limited evidence that Maca actually improves the condition of people having ED. [11]




To reduce the risk of developing an ED, emphasis should be placed on making better life choices such as quitting smoking, reducing alcohol consumption, and exercising. Combining medications with these lifestyle changes has been shown to yield better results in the management of ED. 


Health policy managers and leaders in Africa should support pharmaceutical companies on the continent to standardize and conduct more research on herbs that have been found to be promising in the treatment of erectile dysfunction.




1. Johns Hopkins Medicine. Erectile Dysfunction [internet, n.d] cited April 13, 2024. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/erectile-dysfunction.

2. Ayta IA, McKinlay JB, Krane RJ. The likely worldwide increase in erectile dysfunction between 1995 and 2025 and some possible policy consequences. BJU Int. 1999 Jul;84(1):50-6. doi: 10.1046/j.1464-410x.1999.00142.x. 

3. Panchatsharam PK, Durland J, Zito PM. Physiology, Erection. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513278/

4. Burnett AL, Nehra A, Breau RH et al: Erectile dysfunction: AUA guideline. J Urol 2018; 200: 633. Available from: https://www.auanet.org/guidelines-and-quality/guidelines/erectile-dysfunction-(ed)-guideline.

5. Pasmanter N, Iheanacho F, Hashmi MF. Biochemistry, Cyclic GMP. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542234/

6. Dhaliwal A, Gupta M. PDE5 Inhibitors. [Updated 2023 Apr 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549843/

7. Traish A, Kim N. The Physiological Role of Androgens in Penile Erection: Regulation of Corpus Cavernosum Structure and Function. The Journal of Sexual Medicine, Volume 2, Issue 6,2005, Pages 759-770. https://doi.org/10.1111/j.1743-6109.2005.00094.x. Available from: https://www.sciencedirect.com/science/article/pii/S1743609515312546)

8. Gooren L. New insights into a driven treatment of erectile dysfunction. Indian Journal of Paediatric Dermatology 22(3):p 231-234, Jul-Sep 2006. DOI: 10.4103/0970-1591.27630. Available from:https://journals.lww.com/indianjurol/fulltext/2006/22030/new_insights_into_androgen_treatment_of_erectile.11.aspx.

9. Wibowo DNSA, Soebadi DM, Soebadi MA. Yohimbine as a treatment for erectile dysfunction: A systematic review and meta-analysis. Turk J Urol. 2021 Nov;47(6):482-488. doi: 10.5152/tud.2021.21206.

10. Ojewole JA. African traditional medicines for erectile dysfunction: elusive dream or imminent reality? Cardiovasc J Afr. 2007 Jul-Aug;18(4):213-5. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170225/

11. Lee HM, Lee MS, Kil KJ. Maca (L. meyenii) for erectile dysfunction: a systematic review and meta-analysis. Journal of Men's Health. 2023. 19(1);1-6. Available from: https://www.jomh.org/articles/10.22514/jomh.2023.003



Recommended reading:

Erectile Dysfunction in Nigerian Men

Be aware: Erectile Dysfunction in Younger Men Often a Sign of Diabetes



Published: April 17, 2024

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