Tadalafil (Cialis) Interactions You Should Know About

For some, tadalafil (Cialis) may be a preferred medication to get or maintain an erection.

Why? Because tadalafil lasts longer than other similar medications.

However, high blood pressure and heart disease are also more common as men get older. And medications used to treat them can interact with tadalafil. Some interactions can have dangerous effects and should be avoided altogether. Others just require monitoring.

Your regular provider, or a telehealth service like GoodRx Care, may have prescribed tadalafil for your ED. In any case, it’s important to know about tadalafil interactions and how to manage them.

Common tadalafil interactions you should be aware of

Tadalafil is a phosphodiesterase-5 (PDE-5) inhibitor commonly used to treat ED. But it can be used to treat other medical conditions, too. This includes symptoms of benign prostatic hyperplasia (BPH) with or without ED. It’s also available as Adcirca and Alyq for treating pulmonary hypertension.

No matter why you’re taking tadalafil, these interactions still apply. Some people take tadalafil daily, while others only take it as needed. And one dose can stick around in your body for several days. This can result in interactions — even if you didn’t take tadalafil and another medication on the same day. So, it’s best to check with your healthcare provider first before starting a new medication.

Below, we’ll detail nine of the most common tadalafil interactions to keep in mind.

1. Nitrates

Nitrates are used to treat and prevent angina (chest pain) caused by heart disease. Examples include nitroglycerin (Nitrostat), isosorbide mononitrate (Monoket), and isosorbide dinitrate (Isordil).

PDE-5 inhibitors, like tadalafil, are contraindicated with nitrates. This means the combination should be avoided since it can cause harm. Taking these medications together can result in a severe drop in blood pressure (called hypotension). This can make you feel dizzy and possibly cause you to faint or pass out.

2. Alpha blockers

Alpha blockers are a medication class used to treat high blood pressure. Some are also used to help with urinary symptoms from BPH. Examples include terazosin (Hytrin), tamsulosin, (Flomax), and doxazosin (Cardura). Alpha blockers can cause your blood vessels to widen. This can result in a decrease in your blood pressure.

Tadalafil also causes your blood vessels to widen. So taking an alpha blocker with tadalafil can significantly reduce your blood pressure. This can cause dizziness and fainting in some people. If you’re taking tadalafil for ED, use caution when taking these medications together. However, it’s not recommended to take them together at all for BPH.

Let your healthcare provider know if you experience dizziness or fainting with this combination.

3. Blood pressure medications

It’s not uncommon to take a blood pressure medication with tadalafil. That’s because having high blood pressure can be a contributing factor for ED. What’s more, some blood pressure medications can also cause ED.

There are several types of medications available to lower your blood pressure if it’s too high. And they all work differently to achieve this effect. Examples include diuretics (water pills), angiotensin-converting enzyme (ACE) inhibitors, and calcium channel blockers. When they’re taken with tadalafil, some people experience a small drop in blood pressure.

This interaction may not cause meaningful blood pressure changes for everyone. But it’s still important to use caution with this combination.

4. sGC stimulators

Riociguat (Adempas) is used to control pulmonary hypertension. And vericiguat (Veroquvo) is used in certain types of heart failure. Both medications are soluble guanylate cyclase (sGC) stimulators. They work by relaxing blood vessels to improve blood flow.

Like nitrates, these medications should not be taken with tadalafil. That’s because your blood pressure could drop dangerously low with this combination.

5. PDE-5 inhibitors

As discussed earlier, tadalafil is a PDE-5 inhibitor. Other common examples of this class include sildenafil (Viagra, Revatio) and vardenafil (Levitra).

For most people, taking more than one PDE-5 inhibitor may not provide an added benefit. Instead, you may be more likely to experience side effects, like dizziness, headache, and flushing.

Your healthcare provider may recommend taking two PDE-5 inhibitors in certain situations. But you should always check with them before taking more than one of these medications at the same time.

6. Protease inhibitors

Protease inhibitors are medications used to treat viral infections like hepatitis C and HIV. Examples include ritonavir (Norvir), darunavir (Prezista), and atazanavir (Reyataz). Sometimes they’re combined with medications to help them work better. One example of this is Paxlovid (nirmatrelvir/ritonavir) for COVID-19.

Ritonavir has been shown to raise the blood levels of tadalafil when taken together. Other protease inhibitors may have a similar interaction. This can increase the risk of side effects like vision changes, low blood pressure, and prolonged erections.

Your healthcare provider may limit your tadalafil dosage with this combination. This may depend on how often you’re taking it.

7. Anti-infective medications

Certain anti-infective medications, including antibiotics and antifungals, interact with many medications. Examples of these include erythromycin (Ery-Tab), ketoconazole, and itraconazole (Sporonax).

Similar to protease inhibitors, these medications may increase tadalafil levels in the blood. This may result in dizziness and fainting. Your tadalafil dosage may need to be adjusted if you’re also taking one of these medications.

8. Grapefruit

You’ve probably heard that grapefruit can interact with medications. And tadalafil — as well as other PDE-5 inhibitors — is no exception. For some people, this combination may cause a drop in blood pressure. But this can vary by person.

Is consuming grapefruit or grapefruit juice part of your regular routine? If so, ask your healthcare provider about how much is safe with your medications.

9. Alcohol

Both tadalafil and alcohol can cause your blood vessels to relax. When you combine the two, this effect can cause your blood pressure to drop. This may be more apparent when changing positions (like from sitting to standing). You may feel dizzy and be more likely to fall.

Because of this, it’s best to minimize or avoid alcohol while taking tadalafil. And if you’re taking tadalafil for ED, alcohol isn’t going to do you any favors. Talk to your healthcare provider about how much alcohol is safe for you to drink.