Udenafil belongs to the class of sex stimulant drugs that are similar in function and structure to Viagra. This medication is a relatively new long-acting medication used to treat erectile dysfunction in men.

Read on to learn more about the drug, its mechanism of action, benefits, side effects, dose, and cost.

What is Udenafil?

Udenafil is a PDE5 inhibitor that was developed by Dong-A Pharmaceuticals for the treatment of erectile dysfunction and pulmonary arterial hypertension.

Manufactured under the trade name of Zydena, this drug is a new addition to the PDE5 inhibitors drug class. It was developed as a potent, longer-lasting medication to combat the efficiency problems of other drugs in the same class.

Udenafil works to dilate the smooth muscles of the corpus cavernosa and the penile blood vessels to increase blood flow through them and induce a penile erection.

Udenafil’s duration of action is relatively longer than other PDE5 inhibitors, making it suitable for once-daily dosing for treating ED.

Currently, it is approved in Korea and 14 other countries for the treatment of ED. It has not yet been approved by the US FDA. It is also undergoing clinical trials to treat pulmonary arterial hypertension [1, 2].

What Is the Dose of Udenafil?

One of the key differences between udenafil and other PDE5 inhibitors is that it is long-acting [3, 4]. This helps men achieve a spontaneous erection throughout the day.

This is in contrast to other medications that require on-demand doses, i.e., the drug should be taken within an hour of anticipated sexual intercourse [11].

Udenafil is available as oral tablets in four different dosages:

  • 50 mg
  • 75 mg
  • 100 mg
  • 200 mg

The starting dose of Udenafil should be begun at the lowest possible amount. It can later be tapered according to individual response and tolerability, under the guidance of a physician.

How Long Does it Take For Udenafil to Kick in?

It takes approximately 30 to 60 minutes for udenafil to kick in, but sexual stimulation is required for it to work. Take the drug one hour before sexual activities. Do not repeat the dose before 24 hours when you take it on an on-demand basis.

If udenafil is taken once daily, it is possible that a spontaneous erection may occur at any time of the day.

How Long Does Udenafil Last?

Udenafil lasts for about 10 to 13 hours.

How Much Does Udenafil Cost?   

The price ranges from $8.25 to $15.25 per pill.

Udenafil is available in strips with four pills, eight pills, and 20 pills priced at $60.99, $94.99, and $164.99, respectively.

History Of Udenafil

Udenafil was developed in Korea by Dong-A Pharmaceutical under the trade name Zydena. It was approved for the treatment of ED in 2005.

Since then, it has been registered in 14 other countries and is available by various other trade names like Zudena, Udzire, and Actizia. It has not been approved yet by the FDA.

Udenafil is currently used for the treatment of erectile dysfunction. It is under clinical trials for the treatment of pulmonary arterial hypertension. The use of udenafil in patients with single-ventricle heart disease is currently under review by the FDA [5].

Who Should Take Udenafil?

Men above the age of 18 years with erectile dysfunction of any organic cause can take Udenafil.

Is Udenafil Safe?

Yes, udenafil is safe. There have been many studies that have proven it to be a safe and effective drug for ED patients [3, 4, 6].

Some common side effects that may occur while taking udenafil include:

  • Dizziness
  • Dyspepsia
  • Flushing
  • Headache
  • Hearing loss
  • Nasal congestion
  • Nasal hemorrhage
  • Palpitation
  • Prolonged erection
  • Rash
  • Redness in eye
  • Shortness of breath
  • Spontaneous penile erection
  • Visual disturbance

Compared to other PDE5 Inhibitors, it does not cause muscle or back pain.

Most of these side effects are mild and self-limiting. If any symptom becomes intolerable, discontinuation of the drug is advised.

Potential Drug Interactions With Udenafil

Some drugs interact with udenafil, so make sure you’re doctor knows about any other medications you use.


Nitrates are vasodilators that are used to treat angina. The use of nitrates with udenafil and any other PDE5 inhibitors is contraindicated as it can cause a drastic drop in blood pressure.


According to various studies, using udenafil in hypertensive patients taking multiple antihypertensives did not produce any significant hemodynamic changes. It did not increase the frequency or severity of any adverse effects [7].

However, anti-hypertensives under the class of alpha-blockers must be used cautiously with udenafil as they potentiate each other’s hypotensive action.

Guanylyl Cyclase (GC) Stimulators

Avoid using PDE5 inhibitors with GC stimulators, as they can interact and lead to a rapid drop in blood pressure. However, no individual studies about the interaction between udenafil and GC stimulators have been conducted.


The use of alcohol with PDE5 Inhibitors is not advised as it can increase the severity of adverse effects like chest discomfort and dizziness [8].

CYP3A4 Inducers

These medications induce the liver CYP3A4 enzyme responsible for the metabolism of udenafil. Hence their use together leads to faster metabolism of udenafil and decreased drug effect.  

Some common CYP3A4 inducers include rifampin, carbamazepine, phenytoin, and phenobarbitone.

CYP3A4 Inhibitors

Udenafil undergoes metabolism in human liver microsomes mainly via cytochrome P450 (CYP3A4). The administration of CYP3A4 inhibitors with udenafil leads to an increase in the half-life of the latter.

Common CYP3A4 inhibitors include ritonavir, ketoconazole, itraconazole, erythromycin, and grapefruit.


According to a study, a low-fat diet tends to decrease the absorption rate of udenafil compared to high-fat meals [9]. This study showed that only the absorption rate of udenafil was affected, not the bioavailability.


Antacids should be taken separately. If taken together with udenafil, it can slow the latter’s absorption.

Who Should Avoid Using Udenafil?

Always consult your physician before taking udenafil to avoid any potential risks.

Here are some conditions contraindicated with udenafil:

  • Severe heart disease
  • Severe liver disease
  • NAION or “crowded” optic disc
  • Retinitis pigmentosa
  • Known hypersensitivity to any PDE5 inhibitors
  • A history of priapism

How Does Udenafil Work?

Udenafil is a PDE5 inhibitor class of drug. It inhibits the enzyme phosphodiesterase type 5, which is responsible for the degradation of cGMP in the smooth muscles of the corpus cavernosum.

During sexual stimulation, nitric oxide (NO) is produced by the endothelial cells and neuronal endings of the penis. NO then travels to the smooth muscle cells and binds to guanylate cyclase receptors leading to activation of guanylate cyclase (GC). The GC then produces cGMP from GTP.

cGMP is present at high levels after the use of udenafil. The cGMP formed activates cGMP-dependent protein kinase. This, in turn, activates certain proteins resulting in decreased intracellular calcium.

Low intracellular calcium causes vascular and smooth muscle relaxation and increases blood flow to the spongy corpus cavernosa, ultimately causing penile erection. This erection is maintained until sexual stimulation is withdrawn.

Udenafil cannot work without sexual stimulation. To get the desired results, it is advised to take this medication one hour before the anticipated sexual intercourse.

Medical Research Involving Udenafil

Many studies have been conducted in test animals and human groups to establish the efficacy and safety of udenafil.

Some important research involving udenafil done over the years are summarized below:

  • Efficacy of once-daily administration of udenafil for 24 weeks on erectile dysfunction [4].

A group of 346 ED patients was randomized into a study group and a placebo group. The study group was given 50 mg and 75 mg udenafil every day for 24 weeks.

At the end of the study, researchers concluded that the study group who received 50 mg showed improvement, and the ones that received 75 mg showed significant improvement regardless of the baseline degree of ED compared to the ones who received the placebo.

  • The efficacy and safety of udenafil [Zydena] for treating erectile dysfunction in hypertensive men taking concomitant antihypertensive agents [7].

A clinical trial was conducted with 165 ED patients receiving antihypertensive medication. They were randomized into a placebo and study group. The study group received 100 mg and 200 mg of udenafil for 12 weeks.

At the end of the study, researchers concluded that patients receiving both doses of udenafil showed significantly improved erectile function among ED patients with hypertensive symptoms treated with concomitant antihypertensive medication than the placebo group. The treatment did not increase the frequency or severity of adverse events.

Best Udenafil Alternatives

There are many ED medications, some using the same active ingredients, others with separate ingredients that share the same mechanism of action.

Pharmaceutical  Alternatives To Udenafil

Udenafil is a generic medication. It is also manufactured by many other companies; some are cheaper, and some are expensive, but all contain the same compound and dose.

Here is a list of similar medications:

  • Avanafil (Avaforce, Stendra, Avana)
  • Mirodenafil (Mvix)
  • Sildenafil (Viagra, Fildena, P-Force, Vygex)
  • Tadalafil (Cialis, Tadagra, Tadovas, Tadact, Tadacip, Tadalip)
  • Vardenafil (Levitra, Vilitra, Savitra)

Natural Alternatives to Udenafil

It is always advised to make lifestyle changes like diet modifications, meditation, and exercise to keep the body and mind healthy to reduce stress levels that might be causing ED.

There are some herbs and nutrients that can also help facilitate erection. These herbal compounds are effective but also have side effects.

Ginseng (Panax ginseng)

Various studies have shown the benefit of Korean red ginseng for ED [10, 11]. It induces the release of NO and relaxes the smooth muscles of the corpus cavernosum.


A study in the Journal of Sex and Marital Therapy found that L-arginine and Pycnogenol supplements helped many men aged 25 to 45 with ED achieve normal erections. The treatment also did not cause side effects with ED medications [12].

Muira Puama (Ptychopetalum olacoides)

It is an herb that is used for libido and penile erections. It is rich in sterols, e.g., sitosterol, campesterol, and lupeol. It activates the body’s receptors for hormones like testosterone to heighten libido and enhance performance.

Also present are volatile oils like camphor, which help restore sex drive, inner depth of libido, and the mental ability to be aroused.

Catuaba (Erythroxylum catuaba)

Catuaba extract is considered a central nervous system stimulant without the side effects of caffeine. This is used in some Asian remedies for sexual issues and low libido.

Yohimbe (Pausinystalia yohimbe)

It blocks alpha-2 adrenergic activity allowing vasodilation. It also acts as a monoamine oxidase inhibitor increasing serotonin in the brain. Yohimbine has a dual aphrodisiac function. Side effects include nervousness, anxiety, insomnia, and possibly mild hypertension.

Tribulus (Tribulus terrestris)

It improves sexual activity by increasing the levels of testosterone and NO synthesis.

Where to Buy Udenafil?

Udenafil can only be purchased with a doctor’s prescription. It is marketed in Korea and 14 other countries, including Brazil, Algeria, Belarus, Turkey, Ukraine, Jordan, Azerbaijan, Uzbekistan, Russia, Kyrgyzstan, Mongolia, the Philippines, Malaysia, and India.

Always consult your doctor before using this drug to avoid potential risks.

You can buy udenafil from any authorized pharmacy or online.

Most patients prefer to order their medications online. Buying online allows buyers to compare prices and have easy access to information and reference sources. Furthermore, it gives the privacy that many with ED seek.


  1. Chang, H. J., Song, S., Chang, S. A., Kim, H. K., Jung, H. O., Choi, J. H., … & Kim, D. K. (2019). Efficacy and safety of udenafil for the treatment of pulmonary arterial hypertension: a placebo-controlled, double-blind, phase IIb clinical trial. Clinical therapeutics, 41(8), 1499-1507.
  2. Kim, H. Y., & Kim, K. H. (2019). Udenafil as a therapeutic option for pulmonary arterial hypertension. Korean circulation journal, 49(4), 361-362.
  3. Zhao, C., Kim, S. W., Yang, D. Y., Kim, J. J., Park, N. C., Lee, S. W., … & Park, J. K. (2011). Efficacy and safety of once-daily dosing of udenafil in the treatment of erectile dysfunction: results of a multicenter, randomized, double-blind, placebo-controlled trial. European urology, 60(2), 380-387.
  4. Moon, K. H., Ko, Y. H., Kim, S. W., Moon, D. G., Kim, J. J., Park, N. C., … & Park, K. (2015). Efficacy of Once‐Daily Administration of Udenafil for 24 Weeks on Erectile Dysfunction: Results from a Randomized Multicenter Placebo‐Controlled Clinical Trial. The journal of sexual medicine, 12(5), 1194-1201.
  5. Goldberg, D. J., Zak, V., Goldstein, B. H., Schumacher, K. R., Rhodes, J., Penny, D. J., … & Pediatric Heart Network Investigators. (2020). Results of the FUEL trial. Circulation, 141(8), 641-651.
  6. Ortaç, M., Çayan, S., Çalışkan, M. K., Yaman, M. Ö., Okutucu, T. M., Semerci, M. B., … & Kadıoğlu, A. (2013). Efficacy and tolerability of udenafil in Turkish men with erectile dysfunction of psychogenic and organic aetiology: a randomized, double‐blind, placebo‐controlled study. Andrology, 1(4), 549-555.
  7. Paick, J. S., Kim, S. W., Park, Y. K., Hyun, J. S., Park, N. C., Lee, S. W., … & Chung, W. S. (2009). ED PHARMACOTHERAPY: The Efficacy and Safety of Udenafil [Zydena] for the Treatment of Erectile Dysfunction in Hypertensive Men Taking Concomitant Antihypertensive Agents. The journal of sexual medicine, 6(11), 3166-3176.
  8. Kim, J. N., Oh, J. J., Park, D. S., Hong, Y. K., & Yu, Y. D. (2019). Influence of Alcohol on Phosphodiesterase 5 inhibitors Use in Middle-to Old-Aged Men: A Comparative Study of Adverse Events. Sexual medicine, 7(4), 425-432.
  9. Kim, T. E., Kim, B. H., Kim, J. R., Lim, K. S., Hong, J. H., Kim, K. P., … & Yu, K. S. (2009). Effect of food on the pharmacokinetics of the oral phosphodiesterase 5 inhibitor udenafil for the treatment of erectile dysfunction. British journal of clinical pharmacology, 68(1), 43-46.
  10. De Andrade, E., De Mesquita, A. A., de Almeida Claro, J., De Andrade, P. M., Ortiz, V., Paranhos, M., … & Erdogrun, T. (2007). Study of the efficacy of Korean Red Ginseng in the treatment of erectile dysfunction. Asian journal of andrology, 9(2), 241-244.
  11. Hong, B., Ji, Y. H., Hong, J. H., Nam, K. Y., & Ahn, T. Y. (2002). A double-blind crossover study evaluating the efficacy of korean red ginseng in patients with erectile dysfunction: a preliminary report. The Journal of urology, 168(5), 2070-2073.
  12. Stanislavov, R., & Nikolova, V. (2003). Treatment of erectile dysfunction with pycnogenol and L-arginine. Journal of Sex &Marital Therapy, 29(3), 207-213.
  13. Kang, S. G., & Kim, J. J. (2013). Udenafil: efficacy and tolerability in the management of erectile dysfunction. Therapeutic advances in urology, 5(2), 101-110.






Leave a Reply

Your email address will not be published. Required fields are marked *