Tadalafil and Levetiracetam: Can They Be Taken Together?

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Key takeaways

• No major interaction is commonly reported between tadalafil and levetiracetam.
• Always declare levetiracetam and all other medicines during your online consultation.
• Continue taking your epilepsy medicine exactly as prescribed—never stop without medical advice.
• Your prescriber reviews your full medical history to ensure tadalafil is safe for you.
• Seek urgent help for erections lasting over four hours or sudden vision or hearing loss.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [3][4]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused. This helps you get and keep an erection suitable for sexual activity.

Tadalafil is available in two forms: on-demand tablets (usually 10 mg or 20 mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) and daily low-dose tablets (2.5 mg or 5 mg taken once a day) [4]. It does not work automatically—you still need sexual stimulation for it to be effective. Tadalafil is the active ingredient in branded Cialis and is also available as a generic medicine at lower cost.

At Cured Pharmacy, tadalafil is available on prescription after an online consultation with a UK-registered prescriber, who will check your medical history and current medicines to ensure it is safe for you.

What Is Levetiracetam and Why Is It Prescribed?

Levetiracetam is an antiepileptic medicine (also called an anticonvulsant) used to prevent and control seizures in people with epilepsy. It is often prescribed on its own or alongside other antiepileptic drugs to manage different types of seizures, including focal seizures, generalised tonic-clonic seizures, and myoclonic seizures.

Levetiracetam works by stabilising electrical activity in the brain, helping to reduce the frequency and severity of seizures. It is usually taken twice a day, and the dose is tailored to each person's needs. Common brand names include Keppra, but generic levetiracetam is widely available.

Because levetiracetam is a long-term treatment for a serious condition, it is essential that you continue taking it exactly as prescribed by your doctor. You should never stop or change your epilepsy medicine without medical advice, even if you are starting a new treatment for erectile dysfunction.

How Levetiracetam Differs from Other Antiepileptics

Unlike some older antiepileptic medicines (such as carbamazepine or phenytoin), levetiracetam does not strongly affect the liver enzymes that break down other drugs. This means it is less likely to cause significant drug interactions compared to enzyme-inducing antiepileptics, which can reduce the effectiveness of many medicines, including some treatments for erectile dysfunction.

At a glance

Do Tadalafil and Levetiracetam Interact with Each Other?

Based on current clinical evidence and prescribing guidance, there is no major direct interaction commonly reported between tadalafil and levetiracetam [3][4]. Levetiracetam does not significantly affect the liver enzymes (CYP3A4) responsible for breaking down tadalafil, so it is unlikely to alter tadalafil levels in your body or reduce its effectiveness.

However, it is important to remember that every person's health is different. Your prescriber will always review your full medical history, including your epilepsy, any other conditions you have, and all the medicines you take (prescription, over-the-counter, and herbal), before deciding whether tadalafil is suitable for you.

Some antiepileptic medicines—particularly enzyme inducers like carbamazepine, phenytoin, and phenobarbital—can reduce the effectiveness of PDE5 inhibitors by speeding up their breakdown in the body. Levetiracetam does not have this effect, which is one reason it is generally considered compatible with tadalafil when prescribed appropriately.

What Does Your Prescriber Check Before Approving Tadalafil and Levetiracetam Together?

When you request tadalafil through Cured Pharmacy, a UK-registered prescriber will review your online consultation to ensure the medicine is safe for you. They will check your current medicines, including levetiracetam, to identify any potential interactions or contraindications.

The prescriber will also assess your overall health, including your heart and blood pressure, because tadalafil can lower blood pressure slightly. If you take other medicines that also lower blood pressure (such as some treatments for high blood pressure or an enlarged prostate), the prescriber will consider whether the combination is safe and may recommend starting on a lower dose of tadalafil.

You must declare all your current medicines during the consultation, including levetiracetam and any other antiepileptics, as well as any over-the-counter products or supplements. This helps the prescriber make an informed decision and ensures your safety.

Why Honesty in Your Consultation Matters

It can be tempting to leave out information, especially if you are worried a medicine might be refused. However, full disclosure protects you. The prescriber is not there to judge—they are there to ensure any treatment is safe and effective for your individual circumstances. If tadalafil is not suitable, they may suggest an alternative or recommend you speak to your GP.

Practical Advice for Taking Tadalafil and Levetiracetam Safely

If your prescriber approves tadalafil, continue taking levetiracetam exactly as your doctor has prescribed. Do not stop, reduce, or change the timing of your epilepsy medicine without medical advice, as this could increase your risk of seizures.

Take tadalafil as directed—either on-demand (at least 30 minutes before sexual activity) or daily, depending on the dose prescribed. Do not take more than one dose in 24 hours. Remember that tadalafil only works when you are sexually aroused; it does not cause an automatic erection.

Avoid drinking large amounts of alcohol, as heavy drinking can worsen erectile dysfunction and increase the risk of side effects such as dizziness or low blood pressure. Grapefruit juice can raise tadalafil levels in your blood, so it is best to avoid it while using this medicine. If you experience any new or unusual symptoms after starting tadalafil, contact your prescriber or GP for advice.

When to Seek Medical Help and Warning Signs to Watch For

Most men tolerate tadalafil well, but it is important to know the warning signs that require urgent medical attention. If you develop an erection that lasts longer than four hours (priapism), go to A&E immediately, as this can cause permanent damage if not treated quickly.

Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects. Stop taking tadalafil and seek medical help straight away if this happens. If you experience chest pain during or after sex, do not use nitrate medicines (such as GTN spray)—call 999 and tell the paramedics you have taken tadalafil.

If you notice any increase in seizure frequency or severity after starting tadalafil, contact your GP or epilepsy specialist promptly. While there is no known interaction that would cause this, any change in your condition should be reviewed by a doctor. Never stop levetiracetam suddenly, as this can trigger seizures.

Common Side Effects of Tadalafil

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a blocked or runny nose [4]. These are usually mild and go away on their own. If side effects are troublesome or persistent, speak to your prescriber—they may be able to adjust your dose or suggest an alternative treatment.

When to get urgent help

• Erection lasting longer than four hours (priapism)—go to A&E immediately
• Sudden loss of vision in one or both eyes—stop tadalafil and seek urgent medical help
• Sudden decrease or loss of hearing, sometimes with ringing or dizziness—stop tadalafil and see a doctor
• Chest pain during or after sex—call 999 and tell paramedics you have taken tadalafil
• Increase in seizure frequency or severity—contact your GP or epilepsy specialist promptly

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.

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