What Cialis is and how the body clears it
Cialis is the brand name of tadalafil, a medicine made by Eli Lilly for erectile dysfunction and enlarged prostate. It relaxes blood vessels in the penis so more blood can flow in during arousal. It lasts up to 36 hours, which is longer than sildenafil, the drug in Viagra.
Your liver breaks down tadalafil using an enzyme called CYP3A4. Enzymes are proteins that take medicines apart so your body can get rid of them. The faster the enzyme works, the sooner the drug leaves your body.
Zen IV Spa prescribes generic tadalafil as part of our $129 ED program. Generic tadalafil is FDA-approved and contains the same active ingredient as Cialis.
What grapefruit does
Grapefruit contains chemicals called furanocoumarins. These block the CYP3A4 enzyme in the gut and liver. When the enzyme is blocked, medicines that depend on it build up to higher levels in the blood than they normally would.
This effect is well documented for drugs like some statins, blood pressure pills, and certain sedatives. For some of those, grapefruit can double or triple the blood level and cause serious problems.
The effect can last for a day or more after drinking grapefruit juice, because the enzyme has to be rebuilt. One glass is enough to matter for strongly affected drugs.
How much grapefruit affects tadalafil
The Cialis prescribing information lists grapefruit juice as a mild CYP3A4 inhibitor that may raise tadalafil levels. It does not forbid grapefruit, but it recommends caution. Strong CYP3A4 blockers like the antifungal ketoconazole raise tadalafil levels much more, by about four times.
Grapefruit is a weaker blocker than those drugs. The real-world effect is a modest rise in tadalafil levels, which could make side effects a bit more likely or last a bit longer.
No studies have shown dangerous events from grapefruit plus tadalafil alone. Most men who have an occasional grapefruit will not notice anything. Still, there is no reason to take the chance when it is easy to avoid, and men with heart or blood pressure problems should be the most careful.
Side effects that could get stronger
Higher tadalafil levels mean more of its usual side effects: headache, flushing, stuffy nose, back or muscle aches, indigestion, and dizziness. Rarely, low blood pressure. These are not dangerous for most healthy men but are uncomfortable.
The risk is higher if you also take other drugs that block CYP3A4, such as some antibiotics, antifungals, or HIV medicines. Stacking several blockers at once is where real trouble starts.
Never combine tadalafil with nitrates, like nitroglycerin for chest pain, grapefruit or not. That combination can drop blood pressure dangerously.
Practical advice
If you take tadalafil on an as-needed basis, skip grapefruit and grapefruit juice the day before and the day of. If you take daily low-dose tadalafil, it is simplest to avoid grapefruit entirely, since the drug is always in your system.
Other citrus like oranges and lemons do not have this effect. Seville oranges, used in marmalade, and pomelos do. Check juice blends, because some contain grapefruit.
If you have had grapefruit and your dose feels stronger than usual, do not take extra tadalafil. Rest, drink water, and avoid alcohol until it passes.
Getting tadalafil the simple way
Zen IV Spa serves men in New York and New Jersey. Your first video visit with our medical team is free. We review your medicines, including anything that interacts with tadalafil, and check your heart health. If labs are needed, a licensed nurse comes to your home.
Our ED program is $129 and includes generic tadalafil or sildenafil, shipped to you. Learn more at /sexual-wellness/ or call (332) 239-2005.
Common Questions
Can I drink grapefruit juice with Cialis?+
It is best to avoid it. Grapefruit raises tadalafil levels a little, which can make side effects more likely. The label advises caution.
How long should I wait after grapefruit to take tadalafil?+
The enzyme effect can last 24 hours or more. Skipping grapefruit the day before and the day of is a safe rule.
Does grapefruit affect Viagra too?+
Yes. Sildenafil is also cleared by CYP3A4, so grapefruit can raise its level in a similar way.
What other foods interact with Cialis?+
Alcohol in large amounts can add to dizziness and low blood pressure. Seville oranges and pomelos act like grapefruit. Regular oranges are fine.
Is generic tadalafil the same as Cialis?+
Yes. Generic tadalafil is FDA-approved and has the same active ingredient. Zen IV Spa prescribes the generic.
Sources: FDA prescribing information for Cialis (tadalafil), 2023; FDA consumer update, Grapefruit Juice and Some Drugs Don't Mix; Bailey DG et al., Grapefruit-medication interactions, CMAJ 2013.
All treatments are medical services. Every guest is screened, and every treatment is prescribed by a licensed provider. Nothing on this page is medical advice for you personally, and the opinions summarized here belong to the doctors named, not to Zen IV Spa. Talk to a provider before starting or stopping anything.
