Tadalafil and Morphine: Can They Be Taken Together?

Takes less than 2 minutes to complete 100% online

What is tadalafil and how does it work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [4]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Tadalafil is the generic version of Cialis and is available in two forms: on-demand tablets (10mg or 20mg taken at least 30 minutes before sex) and daily tablets (2.5mg or 5mg taken once a day).

One of the key advantages of tadalafil is its long duration of action—the effect can last up to 36 hours, which is why it is sometimes called the 'weekend pill' [4]. This does not mean you will have an erection for 36 hours; rather, you may be able to achieve an erection during this window when sexually stimulated. Tadalafil requires sexual arousal to work and will not cause an automatic erection.

Like all PDE5 inhibitors, tadalafil is only available on prescription in the UK after a consultation with a healthcare professional. At Cured Pharmacy, a UK-registered prescriber reviews your medical history and current medicines to ensure tadalafil is safe and suitable for you.

What is morphine and why is it prescribed?

Morphine is a strong opioid painkiller used to treat moderate to severe pain that cannot be managed with weaker painkillers [12]. It works by binding to opioid receptors in the brain and spinal cord, changing how your body perceives and responds to pain. Morphine is commonly prescribed for pain following surgery, injury, or in conditions such as cancer or severe chronic pain.

Morphine is available in several forms, including immediate-release tablets or liquid (for short-term pain relief) and modified-release tablets or capsules (for continuous pain control throughout the day). Because morphine is a controlled drug, it is only available on prescription and is subject to strict regulations in the UK.

Common side effects of morphine include drowsiness, constipation, nausea, and dizziness. Morphine can also lower blood pressure, particularly when you first start taking it or when the dose is increased. This blood-pressure effect is important when considering whether tadalafil and morphine can be taken together, as both medicines have the potential to cause dizziness or light-headedness.

How morphine affects the body

Morphine acts on the central nervous system to reduce the sensation of pain. It can cause sedation, slow your breathing, and affect your cardiovascular system by dilating blood vessels, which may lead to a drop in blood pressure. These effects are dose-dependent and are more pronounced when you first start treatment or if the dose is increased. Your prescriber will monitor you closely to ensure morphine is working effectively without causing troublesome side effects.

When to get urgent help

• An erection lasting more than 4 hours (priapism)—go to A&E immediately
• Sudden loss of vision or hearing—stop tadalafil and seek urgent medical advice
• Severe dizziness, fainting, or chest pain during or after sex—call 999
• Difficulty breathing or severe drowsiness after taking morphine—call 999
• Any new or worsening symptoms after starting tadalafil—contact your GP or pharmacist the same day

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

Can tadalafil and morphine be taken together?

Yes, tadalafil and morphine can usually be taken together, as there is no major direct drug interaction between them [3][4]. Neither medicine significantly affects the metabolism or action of the other in the body. However, both medicines can lower blood pressure and cause dizziness, so there is a potential for these effects to add together, particularly when you stand up quickly.

Your prescriber will assess your overall health, blood pressure, and other medicines before approving tadalafil. If you are taking morphine for pain, it is essential to declare this during your consultation. The prescriber will consider factors such as how long you have been taking morphine, whether your dose is stable, and whether you experience side effects such as dizziness or drowsiness.

In most cases, if you are stable on morphine and your blood pressure is within a safe range, tadalafil can be prescribed at an appropriate dose. You may be advised to start on a lower dose of tadalafil (for example, 10mg instead of 20mg) to minimise the risk of dizziness. It is important to follow the prescriber's instructions carefully and report any unusual symptoms.

How the interaction between tadalafil and morphine works

The interaction between tadalafil and morphine is not a direct chemical interaction but rather an additive effect on blood pressure. Tadalafil works by relaxing blood vessels, which can cause a mild drop in blood pressure [4]. Morphine can also dilate blood vessels and lower blood pressure, particularly when you move from sitting or lying down to standing (a phenomenon called postural hypotension).

When both medicines are taken together, there is a possibility that their blood-pressure-lowering effects may combine, leading to symptoms such as dizziness, light-headedness, or feeling faint. This is more likely if you are dehydrated, have been drinking alcohol, or are taking other medicines that also lower blood pressure (such as blood-pressure tablets or alpha-blockers for prostate symptoms).

The good news is that this additive effect is usually manageable. Most men taking morphine and tadalafil together do not experience significant problems, especially if they start on a lower dose of tadalafil and avoid sudden changes in posture. If you do feel dizzy, sit or lie down until the feeling passes, and avoid driving or operating machinery until you know how the combination affects you.

What your prescriber will check

Before prescribing tadalafil, your healthcare professional will review your current medicines, including morphine, and ask about your blood pressure, heart health, and any history of dizziness or fainting. They will also check that you are not taking any medicines that are contraindicated with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, or riociguat [3][4]. If you are taking other medicines that lower blood pressure, the prescriber may recommend starting on a lower dose of tadalafil and monitoring how you respond.

At a glance

Practical advice for taking tadalafil and morphine together

If you have been prescribed both tadalafil and morphine, there are several practical steps you can take to use them safely. First, always take each medicine exactly as prescribed. Do not take more tadalafil than recommended, and do not adjust your morphine dose without consulting your doctor. If you are taking on-demand tadalafil (10mg or 20mg), take it at least 30 minutes before sexual activity, and remember that sexual stimulation is needed for it to work [4].

Be mindful of activities that might increase your risk of dizziness. Avoid standing up too quickly, especially after lying down or sitting for a long time. If you feel light-headed, sit or lie down until the sensation passes. Avoid drinking large amounts of alcohol, as this can worsen dizziness and make erectile dysfunction worse. Stay well hydrated, but avoid grapefruit juice, which can increase tadalafil levels in your blood.

If you experience any unusual symptoms—such as severe dizziness, fainting, chest pain, or an erection lasting more than four hours—seek medical help immediately. Contact your GP or pharmacist if you have any concerns about taking tadalafil and morphine together, or if you notice new side effects after starting treatment. Never stop or change your prescribed morphine without medical advice, as this can lead to withdrawal symptoms or uncontrolled pain.

Other medicines and interactions to be aware of

While tadalafil and morphine can usually be taken together, it is important to be aware of other medicines that may interact with tadalafil. Never take tadalafil with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as the combination can cause a dangerous drop in blood pressure [3][4]. Do not take tadalafil with another PDE5 inhibitor, such as sildenafil (Viagra) or vardenafil (Levitra).

If you are taking alpha-blockers for prostate symptoms (such as tamsulosin, doxazosin, or alfuzosin), tell your prescriber, as these medicines can also lower blood pressure when combined with tadalafil [4]. You should be stable on the alpha-blocker before starting tadalafil, and you may need to start on a lower dose. Some medicines can affect how your body processes tadalafil: potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, itraconazole, or clarithromycin) can raise tadalafil levels, while CYP3A4 inducers (such as rifampicin, carbamazepine, or St John's wort) can reduce its effectiveness [4].

During your consultation at Cured Pharmacy, you will be asked to list all your current medicines, including over-the-counter products and herbal supplements. The prescriber will check for interactions and ensure tadalafil is safe for you. If you start a new medicine after being prescribed tadalafil, check with your pharmacist or GP that it is safe to continue.

When tadalafil should not be used

Tadalafil is not suitable for everyone. It should not be used if you have been advised to avoid sexual activity (for example, after a recent heart attack or stroke, or if you have unstable angina or severe heart failure), if you have very low blood pressure, or if you have had a previous episode of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION) [4]. Your prescriber will assess your suitability during the consultation.

In summary

• Tadalafil and morphine can usually be taken together safely with no major direct interaction
• Both medicines may lower blood pressure, so dizziness is possible—stand up slowly
• Always declare morphine and all other medicines during your tadalafil consultation
• Your prescriber will check your blood pressure and may start you on a lower tadalafil dose
• Avoid alcohol and sudden movements to reduce the risk of dizziness

Faq

Choose your treatment

Select from our recommended UK-licensed medications.

Answer quick questions

Select safe UK treatments. Quick answers.

Get it delivered fast

We will deliver direct to you as quickly as tomorrow.

Start Your Assessment For Erectile Dysfunction

Start your journey to better health today.

• Reviewed by UK-based prescribers
• Takes under 3 minutes
• Discreet Packaging