Vardenafil and Chlordiazepoxide: Can They Be Taken Together?

Vardenafil and Chlordiazepoxide: Understanding the Interaction

Published: 28 October 2026

Vardenafil and chlordiazepoxide can generally be taken together, but the combination requires careful monitoring because both medicines can affect your blood pressure and central nervous system. Vardenafil (generic Levitra) is a PDE5 inhibitor used to treat erectile dysfunction, while chlordiazepoxide is a benzodiazepine prescribed for anxiety and alcohol withdrawal. This page explains how these medicines work, the potential interaction, what your prescriber will check, and practical steps to use them safely.

What Is Vardenafil and How Does It Work?

Vardenafil is a prescription medicine licensed in the UK to treat erectile dysfunction (ED) in adult men [5]. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing the blood vessels in the penis, allowing increased blood flow when you are sexually aroused [1].

Vardenafil is available in 5 mg, 10 mg, and 20 mg tablets. The usual starting dose is 10 mg, taken about 25 to 60 minutes before sexual activity [5]. The medicine only works when you are sexually stimulated; it does not cause an automatic erection. You should take vardenafil no more than once a day, and it can be taken with or without food, although a heavy, high-fat meal may delay how quickly it works.

Common side effects include headache, flushing, nasal congestion, and indigestion [5]. Vardenafil can also cause a small, temporary drop in blood pressure, which is usually not a problem for most men but becomes important when combined with other medicines that affect blood pressure or the central nervous system.

What Is Chlordiazepoxide and Why Is It Prescribed?

Chlordiazepoxide is a benzodiazepine medicine used to treat anxiety disorders and to manage the symptoms of alcohol withdrawal. It works by enhancing the effect of a natural chemical in the brain called gamma-aminobutyric acid (GABA), which has a calming effect on the nervous system.

Benzodiazepines like chlordiazepoxide can cause drowsiness, dizziness, muscle relaxation, and a reduction in blood pressure, especially when you first start taking them or when the dose is increased. These effects are usually mild but can be more noticeable if you are also taking other medicines that affect your blood pressure or alertness.

Chlordiazepoxide is typically prescribed for short-term use because long-term use can lead to dependence. If you have been prescribed chlordiazepoxide, it is important not to stop taking it suddenly without medical advice, as withdrawal symptoms can occur. Always tell your prescriber about all medicines you are taking, including those for erectile dysfunction, so they can assess any potential interactions.

The Interaction Between Vardenafil and Chlordiazepoxide

There is no major direct interaction between vardenafil and chlordiazepoxide that would make them absolutely contraindicated (unsafe to take together). However, both medicines can lower blood pressure and cause dizziness or drowsiness, so taking them together may add to these effects [5].

Vardenafil causes blood vessels to relax, which can lead to a small drop in blood pressure. Chlordiazepoxide, as a benzodiazepine, can also cause a mild reduction in blood pressure and has sedative effects that may make you feel lightheaded or unsteady, particularly when standing up quickly. When these effects combine, you may be more likely to experience dizziness, fainting, or a feeling of being off-balance.

This interaction is generally manageable, and many men take both medicines without problems. The key is that your prescriber needs to know about both medicines so they can assess your individual risk, start you on an appropriate dose of vardenafil, and give you clear advice on what to watch for. You should never adjust the dose of either medicine on your own or stop taking a prescribed medicine without speaking to your doctor or pharmacist first.

How the Interaction Works in Plain English

Think of your blood pressure as being controlled by a series of taps and valves. Vardenafil opens the valves in the blood vessels of the penis to allow more blood flow, but it also has a mild effect on blood vessels elsewhere in the body, which can lower your overall blood pressure slightly. Chlordiazepoxide calms your nervous system, which can also relax blood vessels and reduce the signals that keep your blood pressure steady. When both medicines are working at the same time, the combined effect on your blood pressure and balance may be more noticeable than either medicine alone.

What Your Prescriber Will Check Before Prescribing Vardenafil

Before prescribing vardenafil, your prescriber will ask about all your current medicines, including chlordiazepoxide, to check for interactions [2]. They will review your medical history, particularly any heart or blood pressure conditions, and assess whether sexual activity is safe for you.

Your prescriber will check whether you are taking any medicines that are absolutely contraindicated with vardenafil, such as nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs called poppers (amyl or alkyl nitrites). These combinations can cause a dangerous drop in blood pressure and must never be taken together [5].

If you are taking chlordiazepoxide, your prescriber will consider starting you on a lower dose of vardenafil (such as 5 mg) to minimise the risk of dizziness or low blood pressure. They will also advise you to be cautious when standing up quickly and to avoid drinking large amounts of alcohol, which can worsen both the sedative effects of chlordiazepoxide and the blood-pressure-lowering effects of vardenafil. At Cured Pharmacy, every prescription for vardenafil follows an online consultation reviewed by a UK-registered prescriber to ensure it is safe and suitable for you.

Practical Advice for Taking Vardenafil and Chlordiazepoxide Together

If your prescriber has approved the combination of vardenafil and chlordiazepoxide, there are several practical steps you can take to use them safely. First, take each medicine exactly as prescribed, at the dose and time your prescriber has recommended. Do not take more vardenafil than prescribed, even if you feel the first dose did not work as well as you hoped.

Be aware that you may feel more dizzy or lightheaded than usual, especially when you stand up quickly or after drinking alcohol. Sit or lie down if you feel faint, and take your time when getting up from a sitting or lying position. Avoid driving or operating machinery if you feel drowsy or unsteady.

Limit your alcohol intake, as heavy drinking can make erectile dysfunction worse, increase the risk of side effects from both medicines, and add to the drop in blood pressure [1]. If you experience severe dizziness, fainting, chest pain during sex, or an erection lasting more than four hours, seek urgent medical help. Always keep your prescriber and pharmacist informed of any new medicines, over-the-counter products, or herbal supplements you start taking, as these may also interact with vardenafil or chlordiazepoxide.

When to Seek Medical Advice

Contact your GP or pharmacist if you experience persistent dizziness, unusual drowsiness, or any side effects that concern you. If you develop chest pain during sexual activity, stop and seek urgent medical help. An erection lasting more than four hours (priapism) is a medical emergency and requires immediate treatment to prevent permanent damage. Sudden loss of vision or hearing is rare but serious; if this happens, stop taking vardenafil and seek urgent medical attention [5].

Other Medicines and Lifestyle Factors to Consider

In addition to chlordiazepoxide, several other medicines and lifestyle factors can interact with vardenafil. Alpha-blockers (such as doxazosin or tamsulosin, used for prostate problems or high blood pressure) can also lower blood pressure, so if you take one of these, your prescriber will ensure you are stable on the alpha-blocker before starting vardenafil at the lowest dose [5].

Potent CYP3A4 inhibitors, such as ritonavir, cobicistat, ketoconazole, itraconazole, and clarithromycin, can raise the level of vardenafil in your blood. In many cases, vardenafil is contraindicated or requires a significant dose reduction when taken with these medicines, so your prescriber must check the specific product information [5]. CYP3A4 inducers, such as rifampicin, carbamazepine, phenytoin, and St John's wort, can make vardenafil less effective.

Grapefruit juice can also increase vardenafil levels and should be avoided. Other blood-pressure medicines may add to the blood-pressure-lowering effect of vardenafil, which is usually manageable but must be declared during your consultation. If you are taking any medicine not listed here, do not assume the combination is safe; your prescriber and pharmacist will check every current medicine during your consultation. Never stop or change a prescribed medicine without professional advice.

Alternatives to Vardenafil for Erectile Dysfunction

If vardenafil is not suitable for you, or if you experience troublesome side effects, there are other licensed PDE5 inhibitors available in the UK. Sildenafil (generic Viagra) is taken about one hour before sex and is available from £0.45 per tablet at Cured Pharmacy. Tadalafil (generic Cialis) can be taken on-demand (at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low dose; prices start at £7.95. Avanafil (Spedra) works quickly, often within 15 to 30 minutes, and is priced at £20.95. All these medicines require a prescription following an online consultation with a UK-registered prescriber [1][2].

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 28 October 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 28 October 2026]
3. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 28 October 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.

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