Tadalafil and Orlistat: Can You Take Them Together?

Takes less than 2 minutes to complete 100% online

At a glance

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine licensed in the UK for treating erectile dysfunction (ED) [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 [1]. Tadalafil is the active ingredient in branded Cialis and is also available as a generic medicine.

Tadalafil is available in two forms: on-demand tablets (10mg or 20mg) taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours, and daily tablets (2.5mg or 5mg) taken once a day [4]. Both forms require sexual stimulation to work. Tadalafil does not cure ED but can help you achieve and maintain an erection suitable for sexual activity when used as directed.

At Cured Pharmacy, tadalafil is available after an online consultation reviewed by a UK prescriber. The prescriber will check your medical history, current medicines, and cardiovascular health to ensure tadalafil is safe and suitable for you.

What Is Orlistat and How Does It Work?

Orlistat is a weight-loss medicine that works in your digestive system to reduce the amount of fat your body absorbs from food. It blocks enzymes called lipases, which normally break down dietary fat in your intestines. When these enzymes are blocked, about one-third of the fat you eat passes through your body undigested and is removed in your stools.

Orlistat is available in the UK as a prescription medicine (120mg capsules) and as a pharmacy medicine called Alli (60mg capsules), which can be supplied by a pharmacist after a consultation. It is licensed for adults with a body mass index (BMI) of 28 or above (or 30 or above for the prescription strength) and is used alongside a reduced-calorie, lower-fat diet and increased physical activity.

Because orlistat works in your gut rather than being absorbed into your bloodstream in significant amounts, it does not directly affect how most other medicines work in your body. However, it can affect the absorption of fat-soluble vitamins (A, D, E, and K), and your prescriber may recommend a multivitamin supplement taken at a different time of day.

Can You Take Tadalafil and Orlistat Together?

There is no commonly reported major interaction between tadalafil and orlistat. Orlistat works locally in your digestive system and is minimally absorbed into your bloodstream, so it does not interfere with how tadalafil works to improve blood flow to the penis [4]. Tadalafil is absorbed higher up in your digestive tract, before orlistat has its main effect on fat absorption in the small intestine.

However, it is essential to declare all your current medicines—including orlistat, vitamins, herbal remedies, and over-the-counter products—during your consultation for tadalafil. Your prescriber will review your full medication list to check for any potential interactions and ensure that tadalafil is safe for you. This is particularly important because some medicines can affect tadalafil levels in your blood or increase the risk of side effects.

Weight loss achieved through orlistat and lifestyle changes may actually improve erectile function over time. Obesity is a known risk factor for ED, and losing weight can improve blood flow, hormone levels, and overall cardiovascular health [10]. Many men find that addressing weight issues alongside ED treatment leads to better outcomes, but both medicines must be used under professional guidance.

Why Your Prescriber Checks All Your Medicines

Even though tadalafil and orlistat do not have a direct interaction, your prescriber needs to know about all your medicines to assess your overall health and safety. Some medicines can significantly affect tadalafil levels or increase the risk of side effects, such as potent CYP3A4 inhibitors (certain antifungals, antibiotics, and HIV medicines) or alpha-blockers used for prostate or blood pressure problems [4]. Your prescriber will also check that you do not take any medicines that are contraindicated with tadalafil, such as nitrates, nicorandil, riociguat, or other PDE5 inhibitors.

What you need to know

• No major direct interaction is commonly reported between tadalafil and orlistat
• Always declare all medicines during your consultation so your prescriber can review your full medication list
• Weight loss may improve erectile function over time by improving cardiovascular health
• Do not take tadalafil with nitrates, nicorandil, riociguat, poppers, or another PDE5 inhibitor
• Seek urgent help for an erection lasting over four hours or sudden vision or hearing loss

Medicines That Must Not Be Taken with Tadalafil

Do not take tadalafil together with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or amyl/alkyl nitrites (poppers) [4]. The combination can cause a dangerous fall in blood pressure that may be life-threatening. You must also not take tadalafil with another PDE5 inhibitor (sildenafil, vardenafil, or avanafil) at the same time.

If you take alpha-blockers for prostate problems or high blood pressure (such as doxazosin, tamsulosin, alfuzosin, terazosin, prazosin, silodosin, or indoramin), there is a risk of low blood pressure and dizziness when combined with tadalafil [4]. Your prescriber will check that you are stable on your alpha-blocker and will usually start you on the lowest dose of tadalafil. You should not start both medicines at the same time.

Potent CYP3A4 inhibitors—including ritonavir, cobicistat, Paxlovid, ketoconazole, itraconazole, and clarithromycin—can raise tadalafil levels in your blood, increasing the risk of side effects [4]. Your prescriber will adjust your tadalafil dose or advise whether the combination is suitable. CYP3A4 inducers such as rifampicin, carbamazepine, phenytoin, and St John's wort can make tadalafil less effective. Always declare these during your consultation.

What Your Prescriber Checks Before Prescribing Tadalafil and Orlistat

During your online consultation at Cured Pharmacy, the prescriber will ask about your medical history, current medicines, and any allergies. For tadalafil, they will check your cardiovascular health, as PDE5 inhibitors are not suitable when sexual activity is inadvisable—for example, if you have had a recent heart attack or stroke, unstable angina, or severe heart failure [4]. They will also check your blood pressure, as very low blood pressure is a contraindication.

The prescriber will review any history of eye problems, particularly non-arteritic anterior ischaemic optic neuropathy (NAION), a rare condition causing sudden vision loss, or inherited retinal disorders such as retinitis pigmentosa [4]. They will also ask about any history of priapism (prolonged erections), liver or kidney problems, and bleeding disorders. If you take medicines for any of these conditions, the prescriber will assess whether tadalafil is safe and what dose is appropriate.

For orlistat, the prescriber or pharmacist will check your BMI, diet, and weight-loss goals. They will also review any medicines that may be affected by reduced fat absorption, such as some diabetes medicines, thyroid hormones, anticoagulants, and anticonvulsants. If you take both tadalafil and orlistat, the prescriber will ensure that your overall treatment plan is safe and that you understand how to take each medicine correctly.

Declaring Other Blood Pressure Medicines

If you take other medicines for high blood pressure (such as ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, or diuretics), tadalafil may add to the blood-pressure-lowering effect, potentially causing dizziness or light-headedness [4]. This is usually manageable, but your prescriber must know about all your blood pressure medicines so they can assess the risk and advise on the appropriate tadalafil dose. Never stop or change a prescribed medicine without advice from your doctor or pharmacist.

When to get urgent help

• An erection lasting more than four hours (priapism) – go to A&E or call 999 immediately
• Sudden loss of vision or hearing – seek urgent medical help
• Chest pain during sexual activity – stop and seek immediate medical attention
• Signs of a severe allergic reaction (swelling of face, lips, or throat, difficulty breathing) – call 999
• Severe or persistent dizziness or fainting – contact your GP or call 111 for advice

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

Practical Advice for Taking Tadalafil and Orlistat Safely

If you are prescribed both tadalafil and orlistat, take each medicine exactly as directed. Orlistat is usually taken three times a day with meals that contain fat, or up to one hour after a meal. If you skip a meal or eat a meal with no fat, you can skip that dose of orlistat. Tadalafil on-demand tablets are taken at least 30 minutes before sexual activity, while daily tadalafil is taken once a day at the same time each day, regardless of when you plan to have sex [4].

Because orlistat can cause digestive side effects—particularly oily stools, increased bowel movements, and urgency—it is important to follow a lower-fat diet (no more than about 30% of calories from fat) to minimise these effects. Eating a high-fat meal while taking orlistat will make digestive side effects worse. Plan your meals and be aware of toilet access, especially when you first start orlistat.

Avoid drinking large amounts of alcohol when taking tadalafil, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effect, increasing the risk of dizziness [1]. Grapefruit juice can raise tadalafil levels in your blood, so it is best to avoid it. If you experience side effects from either medicine, contact your prescriber or pharmacist for advice. Common side effects of tadalafil include headache, indigestion, back pain, and flushing [4].

When to Seek Urgent Medical Help

Seek urgent medical help if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity while taking tadalafil [4]. Go to A&E or call 999. Priapism requires immediate treatment to prevent permanent damage. If you experience severe digestive symptoms, signs of an allergic reaction (such as swelling of the face, lips, or throat, or difficulty breathing), or any other serious side effects from either medicine, seek medical help straight away.

Ready to Speak to a Pharmacist?

Start your journey to better health today.

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