Zydena (Udenafil)

Introduction

Zydena is a phosphodiesterase-5 (PDE5) inhibitor whose single active ingredient is Udenafil. It is supplied as a 100 mg oral tablet and belongs to the same therapeutic class as sildenafil and tadalafil. The drug is primarily indicated for the treatment of erectile dysfunction (ED) in adult men. In several Asian markets, regulatory agencies have approved Udenafil for this use, and it is sometimes prescribed off-label for pulmonary arterial hypertension or benign prostatic hyperplasia under specialist supervision.

What is Zydena?

Zydena contains the synthetic compound Udenafil (chemical name: 5-[(3-ethyl-4-hydroxy-5-methyl-pyrimidin-2-yl)-methyl]-2-(1-oxo-1-propanoxy)-1-H-pyridine-3-carboxylic acid). Udenafil was developed in the early s by Dong-A Pharmaceutical Co., Ltd. and received its first regulatory approval in South Korea in 2005 for the treatment of erectile dysfunction.

The medication is marketed in tablet form, each containing 100 mg of Udenafil. While Zydena is the brand name used by some distributors, the same active molecule is also marketed under other brand names such as Udenac and Zyprem in different regions.

How Zydena Works

Udenafil inhibits the enzyme phosphodiesterase-5 (PDE5), which normally degrades cyclic guanosine monophosphate (cGMP) in smooth-muscle cells of the corpus cavernosum. By blocking PDE5, Zydena allows cMP to accumulate after sexual stimulation, leading to prolonged smooth-muscle relaxation, arterial inflow, and engorgement of penile tissue.

Key pharmacologic points

• Onset of action: 30-60 minutes after oral ingestion.
• Duration of effect: Up to 12 hours, longer than sildenafil but slightly shorter than tadalafil.
• Metabolism: Primarily hepatic via CYP3A4; the half-life is about 11-13 hours.

These characteristics make Zydena a flexible option for men who desire spontaneity or a longer therapeutic window.

Conditions Treated with Zydena

Approved indication - Erectile Dysfunction (ED)

• Rationale: ED often results from insufficient cGMP-mediated vasodilation. By preserving cGMP, Zydena restores the physiological pathway that leads to erection in response to sexual arousal.
• Clinical evidence: Randomised, double-blind trials in Korean and Japanese populations demonstrated that a 100 mg dose improved International Index of Erectile Function (IIEF) scores by an average of 7-9 points versus placebo (p < .001).

No other indications have received formal regulatory approval in the jurisdictions where Zydena is marketed.

Off-Label and Investigational Uses of Zydena

Important: Off-label use should only be undertaken under direct supervision of a qualified healthcare provider. The efficacy and safety for these applications have not been established by major regulatory bodies.

Is Zydena the Right Medication for You?

Suitable candidates

• Adult men (≥ 18 years) with a confirmed diagnosis of erectile dysfunction.
• Individuals who have adequate sexual stimulation and are not contraindicated for PDE5 inhibition.
• Patients seeking a longer duration of action than that provided by sildenafil but shorter than tadalafil.

Clinical scenarios where Zydena may be preferred

• Need for flexibility in timing of sexual activity (onset within 1 hour, effect lasting up to 12 hours).
• Prior intolerance or insufficient response to other PDE5 inhibitors.
• Co-administration with medications metabolised by CYP3A4, provided dose adjustments and monitoring are performed.

Contraindications & cautions

• Concurrent use of nitrates (e.g., nitroglycerin) or nitric-oxide donors.
• Severe uncontrolled hypertension or recent myocardial infarction (< 30 days).
• Retinitis pigmentosa or other hereditary retinal disorders.
• Significant hepatic impairment (Child-Pugh class C) or severe renal dysfunction (CrCl < 30 mL/min).

Patients with any of the above conditions should discuss alternative therapies with their clinician.

Risks, Side Effects, and Interactions

Common

• Headache
• Flushing
• Nasal congestion
• Dyspeasia (indigestion)
• Myalgia (muscle aches)

These events are usually mild, transient, and resolve without intervention.

Rare

• Visual disturbances (e.g., blurring, color tinge)
• Priapism (prolonged erection > 4 hours)
• Hypotension (systolic < 90 mmHg)

Patients experiencing any rare event should seek medical advice promptly.

Serious

• Cardiovascular events (myocardial infarction, stroke) in patients with pre-existing heart disease.
• Severe allergic reactions (anaphylaxis, angioedema).

Immediate emergency care is warranted for serious reactions.

Drug-Drug Interactions

• Nitrates (e.g., isosorbide dinitrate): Potentiate vasodilatory effect → severe hypotension.
• CYP3A4 inhibitors (ketoconazole, clarithromycin, HIV protease inhibitors): Increase Udenafil plasma concentration; consider dose reduction to 50 mg.
• CYP3A4 inducers (rifampicin, carbamazepine): Reduce efficacy; monitor response.
• Alpha-blockers (tamsulosin, doxazosin): May cause additive blood pressure lowering; start with low Udenafil dose and observe.

Drug-Food Inter- Alcohol: Excessive intake can amplify hypotensive and dyspeptic effects. Moderate consumption (≤ 2 drinks) is generally tolerated.

• High-fat meals: May delay absorption, modestly postponing onset of action.

Use: Dosing, Missed Dose, Overdose

• Standard dosing: One 100 mg tablet taken with water about 30-60 minutes before anticipated sexual activity. Do not exceed one tablet in a 24-hour period.
• Dose adjustments: For patients taking strong CYP3A4 inhibitors, a 50 mg dose is recommended. Elderly patients (≥ 65 years) may also start at 50 mg.
• Missed dose: If an erection is not achieved, a second dose should not be taken within 24 hours.
• Overdose management: Symptoms may include severe hypotension, prolonged erection, or syncope. Seek immediate medical attention; supportive care (intravenous fluids, vasopressors) is the mainstay.

Practical precautions

• Avoid taking Zydena with grapefruit juice, which can inhibit CYP3A4.
• Do not operate heavy machinery or drive a vehicle if you experience dizziness or visual changes.
• Store tablets at 20-25 °C (68-77 °F) in a dry place, away from direct sunlight.

FAQ

• Can I take Zydena if I have high blood pressure? Yes, if your hypertension is wellcontrolled and you are not using nitrate medication. Uncontrolled high blood pressure should be stabilized before starting any PDE5 inhibitor.

• Is it safe to use Zydena with antihistamines for allergies? Antihistamines generally do not interact with Udenafil. However, some sedating antihistamines may cause mild dizziness, so monitor your response.

• Will Zydena affect my heart rhythm? Udenafil does not have a direct effect on cardiac conduction. Patients with known arrhythmias should discuss therapy with their cardiologist, especially if they use other heart-acting drugs.

• How should I store Zydena while traveling abroad? Keep the tablets in their original blister pack, protected from moisture and heat. A small insulated pouch can prevent temperature extremes during long flights.

• Can I take Zydena after a meal? Yes, Zydena can be taken with or without food. A high-fat meal may delay onset by about 30 minutes, so plan accordingly.

• Is Zydena available in a lower strength (e.g., 50 mg)? Currently, commercial formulations are marketed only as 100 mg tablets. Dose reduction is achieved by splitting the tablet, but this should be done only after confirming tablet splitability with the manufacturer or pharmacist.

• What laboratory tests are recommended before starting Zydena? Baseline blood pressure measurement, assessment of cardiac risk factors, and liver/renal function tests are advisable, especially in older adults or those on multiple medications.

• Does Zydena interact with herbal supplements such as ginseng or yohimbine? Ginseng may have synergistic vasodilatory effects, potentially enhancing blood-pressure reduction. Yohimbine can increase sympathetic activity and may counteract the vasodilatory action of Udenafil. Discuss any supplement use with a healthcare professional.

• Can Zydena be used for female sexual dysfunction? While some early studies have explored this off-label use, safety and efficacy in women have not been established, and the medication is not approved for that purpose.

• Will taking Zydena affect drug testing for employment? Udenafil is not typically screened for in standard workplace drug panels. However, specialized testing could theoretically detect PDE5 inhibitors; disclose all medications if you are subject to such testing.

Glossary

Phosphodiesterase-5 (PDE5) inhibitor

A class of drugs that block the PDE5 enzyme, preventing breakdown of cGMP and thereby promoting smooth-muscle relaxation in the genital vasculature.

cGMP (Cyclic guanosine monophosphate)

A second messenger molecule that mediates vasodilation; its accumulation is essential for erection.

Cytochrome P450 3A4 (CYP3A4)

A liver enzyme responsible for metabolising many drugs, including Udenafil; inhibitors or inducers of CYP3A4 can alter drug levels.

Priapism

A prolonged, often painful erection lasting more than four hours; it is a medical emergency requiring prompt treatment.

Buying Zydena from Our Online pharmacy

Patients who encounter limited availability or high out-of-pocket costs for erectile-dysfunction therapy can obtain Zydena through our online pharmacy. We source the medication directly from licensed, overseas manufacturers that adhere to Good Manufacturing Practice (GMP) standards, ensuring product purity comparable to the original market price.

Key benefits

• Cost-effective pricing: Our brokerage model removes middle-man mark-ups, delivering a price close to the manufacturer’s list.
• Verified quality: Each batch is accompanied by an authenticity certificate and undergoes third-party laboratory testing before shipment.
• Discreet, reliable delivery: Packages are sealed in unmarked envelopes and dispatched via express courier (7-day delivery) or regular airmail (approximately 3 weeks), with tracking options available.
• Privacy-focused service: We operate as a pharmacy broker, handling all regulatory paperwork on your behalf while protecting personal identifiers.

For patients who lack insurance coverage for PDE5 inhibitors or who reside in regions where Zydena is not stocked locally, this service offers a secure and affordable pathway to obtain their prescribed medication.

Disclaimer

The information presented about Zydena serves solely for general educational purposes and does not substitute professional medical advice. Treatment decisions, including any off-label applications, must be made under the direct supervision of a qualified healthcare professional. Readers are assumed to be responsible adults capable of making informed health choices. Our online pharmacy provides access to Zydena for individuals who may encounter limited availability through conventional pharmacies or who seek more affordable generic alternatives. Always consult your clinician before initiating, altering, or discontinuing any medication.