Zydena (Udenafil) – Patient Information for the UK

Zydena contains the active substance udenafil. It is a medicine used to treat erectile dysfunction (ED) in adult men. This page explains how Zydena works, how to take it, what to expect, and important safety information for people in the United Kingdom.

Always read the patient information leaflet supplied with your medicine. If you have questions about suitability for you, talk to a pharmacist or a healthcare professional.

Quick overview

• Medicine: Zydena (Udenafil)
• What it treats: Erectile dysfunction (difficulty achieving and/or maintaining an erection)
• How it works: Helps improve blood flow to the penis during sexual stimulation
• Typical timing: Often taken before sexual activity; effects may last for several hours
• Common side effects: Headache, flushing, indigestion, nasal congestion, dizziness
• Important safety note: Do not use with medicines containing nitrates or “poppers”

Basic product information

How Zydena works (mechanism of action)

Zydena belongs to a group of medicines called PDE5 inhibitors. In the body, sexual stimulation releases nitric oxide, which increases levels of a natural messenger called cGMP. cGMP helps relax blood vessels in the penis, allowing more blood to flow and support erection.

Udenafil blocks an enzyme called PDE5. By inhibiting PDE5, it helps prevent the breakdown of cGMP. As a result, during sexual stimulation, blood flow to the penis can improve, making it easier to achieve and maintain an erection.

Important: Zydena works best with sexual stimulation. It does not cause an erection on its own.

Pharmacokinetics (how your body processes it)

Pharmacokinetics describes what happens to a medicine in the body—how it is absorbed, distributed, metabolised, and eliminated. While individual responses can vary, the following points are generally relevant to PDE5 inhibitors like udenafil:

• Absorption: Udenafil is absorbed after oral administration. Peak concentrations typically occur within a few hours.
• Onset: Effects generally begin within the same day of taking the tablet, often after a delay depending on the person and food intake.
• Duration: Udenafil is considered to have a relatively long duration of action compared with some shorter-acting ED treatments, supporting sexual activity over a wider time window.
• Metabolism: The medicine is processed mainly in the liver by enzyme systems (often involving CYP pathways).
• Elimination: Metabolites are cleared from the body, mainly via biliary and/or renal routes.

If you have liver or kidney problems, your doctor or pharmacist may recommend extra caution, because drug handling may be affected.

What Zydena is used for (indications)

Zydena is indicated for the treatment of erectile dysfunction in adult men. ED may have many causes, including stress, relationship factors, smoking, cardiovascular disease, diabetes, high cholesterol, hormonal changes, and certain medications.

Addressing underlying health factors can improve long-term outcomes. If ED is new, persistent, or worsening, it’s a good idea to seek medical advice, as ED can sometimes be an early sign of cardiovascular or metabolic conditions.

Typical dosing and how to take it

The exact dose and frequency should follow the product instructions and advice from a healthcare professional. Typical guidance for PDE5 inhibitors is to use the lowest effective dose.

General approach (common for ED medicines):

• Take Zydena by mouth before sexual activity.
• Try to take it at a consistent time relative to planned intercourse.
• Most men should not take it more than once in a 24-hour period.
• It may take several attempts to find the most suitable timing for your body.

Timing example:

• Many men find it effective when taken approximately 30 minutes to several hours before sex.
• Because response varies—especially with food—consider experimenting within safe limits recommended for your dose.

Important: Do not exceed the recommended frequency. If you miss a planned dose, do not take a double dose.

When it works: timing, sexual stimulation, and expectations

Zydena helps the blood vessels in the penis respond more effectively to normal sexual stimulation. That means:

• Sexual stimulation is necessary: You still need arousal for the medicine to work.
• There may be a “window” of effectiveness: Depending on the individual and conditions, the effect can last for hours.
• First-time users: Effects can be different from person to person. Factors include anxiety, fatigue, alcohol, and timing with food.

If Zydena doesn’t seem to help after several properly timed attempts, it may be worth discussing with a pharmacist or clinician. Sometimes a different strength, different medicine, or addressing lifestyle factors can make a significant difference.

Food interactions and what to eat

Food can influence how quickly and effectively PDE5 inhibitors are absorbed. In general:

• Heavy or fatty meals may delay absorption and reduce or delay the onset of effect.
• If you plan to use Zydena, consider taking it after a lighter meal.
• Taking it on an empty stomach or with a light snack may help some men achieve a more predictable timing.

If you notice slower onset on days you eat a large meal, try adjusting meal size and timing next time, within safe usage instructions.

Alcohol and Zydena

Alcohol may affect erections by reducing sexual arousal, lowering blood pressure, and impairing performance. Alcohol can also increase side effects such as dizziness, flushing, and headaches.

• Moderation is key: If you drink, keep alcohol intake modest.
• Be cautious with multiple drinks: Higher amounts can make ED harder to manage regardless of medicine.
• Safety note: If you feel light-headed or dizzy, avoid driving and avoid additional alcohol.

Because both alcohol and PDE5 inhibitors can influence blood vessels and circulation, some men may feel more dizzy—especially if standing up quickly.

Interactions with other medicines (including nitrates)

The most important drug interaction with PDE5 inhibitors is with nitrates and certain blood-pressure medicines. Combining them can lead to a potentially dangerous drop in blood pressure.

Do not take Zydena with nitrates

• Nitrate medicines used for chest pain (angina), such as glyceryl trinitrate (GTN) or isosorbide compounds.
• “Poppers” (certain recreational nitrite inhalants) can also contain nitrate-like substances and are dangerous with PDE5 inhibitors.

Emergency situations: If you take Zydena and later experience chest pain, tell the medical team that you have taken it. They may need to choose alternative treatments.

Other important interactions

Several other medicine groups can interact with Zydena, either by increasing the level of udenafil in the body or by affecting blood pressure. Common examples include:

• Alpha-blockers for prostate enlargement or high blood pressure (e.g., tamsulosin, doxazosin) – may increase dizziness or low blood pressure in some people.
• Some antibiotics/antifungals and HIV medicines that affect liver enzymes – may increase udenafil exposure.
• Other PDE5 inhibitors – should not be combined.
• Riociguat (for certain lung/cardiovascular conditions) – can cause problematic blood pressure effects when combined with PDE5 inhibitors.

Always provide your pharmacist with a full list of medicines, including over-the-counter products and herbal remedies. If you are unsure, it is safer to ask.

Safety profile: who should be cautious

Zydena is generally well tolerated by many men, but it is not suitable for everyone. Certain conditions require extra caution, and in some cases Zydena may be unsafe.

Seek medical advice before using Zydena if you have:

• Low blood pressure or episodes of fainting
• Severe heart disease or unstable angina
• Significant liver impairment
• Severe kidney impairment (dose adjustments may be needed)
• History of stroke or recent heart attack (timing matters)
• Retinitis pigmentosa (rare inherited eye condition)
• Any condition that increases risk of prolonged erections

Priapism and other urgent symptoms

PDE5 inhibitors can rarely cause an erection that lasts too long (priapism). This is a medical emergency. Get urgent help if you have:

• An erection lasting 4 hours or more
• Severe chest pain, severe dizziness, or fainting
• Sudden vision loss or severe eye symptoms
• Sudden hearing changes

Common side effects and what to do

Side effects are usually mild to moderate and may lessen as your body adjusts. Commonly reported effects for PDE5 inhibitors include:

• Headache
• Flushing (warmth/redness in the face)
• Indigestion or stomach discomfort
• Blocked or runny nose
• Dizziness or light-headedness
• Occasionally back pain or muscle aches

Practical advice:

• Hydrate and avoid sudden standing if you feel dizzy.
• If you experience persistent headaches or dizziness, discuss with a pharmacist.
• Do not drive if you feel unwell, dizzy, or faint.

Practical use tips for better results

Zydena is more likely to help when used correctly and when lifestyle factors support sexual function. Consider these helpful tips:

• Allow enough time: Take the tablet before planned intimacy so it reaches effective levels.
• Keep meals lighter: A heavy/fatty meal may delay onset.
• Manage alcohol: Keep drinking moderate to avoid worsening ED.
• Focus on arousal: Use adequate foreplay and avoid rushing.
• Reduce anxiety: Stress can affect erections. Feeling pressured can make performance harder.
• Consider smoking and exercise: Stopping smoking and improving cardiovascular health can improve ED over time.
• Review other medicines: Some drugs (e.g., certain antidepressants, blood pressure medicines) can affect erections.

If you are using Zydena regularly and still experience problems, it may help to explore potential causes such as diabetes, vascular disease, hormonal imbalance, or medication side effects.

Alternative options to consider

If Zydena isn’t suitable or doesn’t give the expected results, other options may help. These include:

Other PDE5 inhibitors

• Sildenafil (often shorter acting)
• Tadalafil (longer acting for some men)
• Vardenafil (another PDE5 inhibitor option)

Different PDE5 inhibitors have different onset and duration, and some men respond better to one than another.

Non-medicine approaches

• Address underlying health: blood pressure, cholesterol, diabetes, weight, sleep, and stress
• Counselling or sex therapy: particularly when anxiety or relationship factors are involved
• Devices: vacuum erection devices (where appropriate and medically advised)
• Other treatments: for selected cases, clinicians may discuss further options

A pharmacist can help explain which alternatives may be most appropriate based on your situation and safety profile.

UK market and legal context (general information)

In the United Kingdom, medicines are regulated under UK pharmaceutical and medicines legislation and must be supplied through appropriate channels. ED treatments may be available via different routes depending on the product, strength, and regulatory status.

Some ED medicines may be treated as medicines that require online consultation or clinical assessment to confirm suitability and safe use. Availability can depend on:

• Whether the medicine is marketed and authorised for supply in the UK
• Whether it is classified as prescription-only or otherwise regulated
• Age and patient eligibility requirements
• Safety checks for interactions (especially nitrates and cardiovascular medicines)

If you are ordering online, ensure the pharmacy is legitimate, follows UK regulatory requirements, and supplies genuine products with clear packaging and patient information.

Note: If you are unsure about your eligibility or medicines you take, do not use the product until you have confirmed safety with a qualified healthcare professional.

Recent guidance and clinical considerations (UK-relevant)

Guidance for ED management in the UK commonly emphasises:

• Safety-first screening for cardiovascular risk and medicine interactions
• Use of PDE5 inhibitors as first-line pharmacological treatment for many men who are suitable
• Careful review of nitrates and other interacting medicines
• Consideration of lifestyle and underlying causes (e.g., diabetes, smoking, high cholesterol)

Always follow the most current advice available from trusted healthcare sources or your clinician, especially if you have heart disease or take multiple medicines.

Delivery and availability in the UK

Online pharmacies in the UK typically deliver medicines in discreet packaging. Delivery times depend on the provider, your location, and stock availability.

• Availability: Zydena may be available in certain strengths depending on stock.
• Packaging: Sealed product packaging with patient information is typically included.
• Storage: Store tablets as directed on the packaging (commonly at room temperature away from moisture and heat).

Delivery options (standard/express) vary by supplier. If you have a deadline for when you need the medicine, check the estimated dispatch and delivery times before ordering.

Frequently asked questions (FAQ)

1) How quickly does Zydena start to work?

Many men notice effects within a time window after taking Zydena, often after around 30 minutes to a few hours. The exact timing varies and can be delayed by heavy/fatty meals.

2) What if Zydena doesn’t work for me?

ED can have many causes. If you don’t see improvement after several correctly timed attempts, speak to a pharmacist or clinician. They may recommend dose adjustment, switching to another PDE5 inhibitor, or investigating underlying causes.

3) Can I take Zydena with food?

You can, but heavy or fatty meals may delay onset. For more predictable timing, consider taking it after a lighter meal.

4) Can I drink alcohol while using Zydena?

Moderate alcohol is generally safer than heavy drinking, but alcohol can reduce effectiveness and increase side effects like dizziness or flushing. Keep alcohol intake modest.

5) What medicines must I avoid?

Do not use Zydena with nitrates (for angina) or poppers. Also use extra caution with medicines that lower blood pressure, and tell your pharmacist about all medicines you take, including alpha-blockers and certain antibiotics/antifungals or HIV medicines.

6) Is Zydena suitable if I have heart problems?

Some men with stable cardiovascular disease may use PDE5 inhibitors under medical guidance, but others may be at higher risk. If you have heart disease, low blood pressure, or have been advised to avoid sexual activity, seek medical advice first.

7) Will Zydena cure erectile dysfunction?

Zydena helps manage symptoms for sexual activity, but ED may reflect underlying health or lifestyle factors. Addressing these factors can improve long-term outcomes.

8) How long does Zydena last?

Udenafil is typically considered to have a longer duration compared with some shorter-acting ED medicines. Many men can plan sexual activity within a several-hour window, but individual duration varies.

9) What should I do if I get side effects?

Mild side effects often improve. If dizziness is significant, avoid driving and do not stand up quickly. If you have chest pain, fainting, or an erection lasting 4 hours or more, seek urgent medical help.

10) Can women or children use Zydena?

Zydena is intended for adult men with erectile dysfunction. It is not for use in women or children.

Important reminders

• Zydena helps erections only with sexual stimulation.
• Do not combine with nitrates or “poppers”.
• Check interactions with your pharmacist, especially if you take medicines for blood pressure, angina, or prostate problems.
• If you experience severe or unusual symptoms, seek urgent medical advice.

If you’d like, you can share (without any personal identifying details) which medicines you currently take and we can help identify common interaction categories to discuss with a pharmacist before using Zydena.