How to Take Cialis: Timing, Food, Alcohol and Dose Guide

How to take Cialis depends on which schedule your doctor prescribes: either one tablet (usually 10 mg to start) at least 30 minutes before expected sex, or one low-dose tablet (2.5 mg or 5 mg) at about the same time every day. You can take it with or without food, never more than once a day, and never with nitrate medicines or “poppers.” Cialis (tadalafil) is one of the main medicines used in erectile dysfunction treatment, and taking it correctly is often the difference between “it doesn’t work” and a good result.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; MedlinePlus — Tadalafil

How to take Cialis: the basics

Cialis is the brand name of tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor. It relaxes the smooth muscle of the erectile tissue so that blood can flow in when you are aroused. It does not cause an erection by itself: the FDA patient information states that some form of sexual stimulation is still needed for an erection to happen.

A few rules apply whatever schedule you use. Swallow the tablet whole with a glass of water; the label says not to split it. Take Cialis no more than once in any 24-hour period, even if the first one seemed weak. Use only one tadalafil product at a time, because the same drug is also sold as Adcirca for pulmonary arterial hypertension.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; NHS — Tadalafil

Cialis lasts much longer than most similar medicines. The label gives a mean half-life of 17.5 hours in healthy men, and the patient leaflet notes that some of the active drug stays in your body for more than 2 days. This long tail is why the timing rules, the alcohol advice and the nitrate warning below matter more than they would for a short-acting tablet. If you are still choosing between brands, our comparison of Viagra vs Cialis explains how onset, duration and food effects differ.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; MedlinePlus — Tadalafil

On-demand vs daily Cialis: which schedule fits you?

The FDA approves two ways to take Cialis for erectile dysfunction (ED). With on-demand (as-needed) dosing, you take one tablet before sex you expect. With once-daily dosing, you take a low dose every day and can have sex at any time between doses. Once-daily tadalafil is also approved for the urinary symptoms of an enlarged prostate (benign prostatic hyperplasia, BPH), alone or together with ED.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH)

The EAU guidelines list on-demand 10 mg and 20 mg and daily 5 mg as the standard tadalafil options, with the on-demand dose adapted to how well it works and how well you tolerate it. Which schedule is “better” is mostly a question of lifestyle: daily use removes the need to plan, while on-demand use means you only take the drug when you need it. We explain the once-daily option, its BPH use and the 2.5 mg vs 5 mg choice in detail in our guide to the tadalafil daily dose, so we will not repeat it here.

Source: EAU Guidelines — Management of Erectile Dysfunction

When to take Cialis before sex

For on-demand use, the FDA counseling section tells patients to take one tablet at least 30 minutes before anticipated sexual activity. Blood levels peak at a median of about 2 hours after a dose, with a range of 30 minutes to 6 hours, so many men find that taking it an hour or two ahead gives more reliable results than taking it at the last minute.

In one trial described in the label, successful erections at or before 30 minutes were reported by 38% of men on 10 mg and 52% on 20 mg, compared with 35% on placebo. The EAU describes a window of effectiveness that starts about 30 minutes after the dose, peaks at around 2 hours and extends up to 36 hours.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; EAU Guidelines — Management of Erectile Dysfunction

Does the time of day matter?

Not for absorption. A pooled pharmacokinetic analysis of 13 studies found that exposure was not substantially affected by the time of dosing. For daily use, pick a time you will remember, such as with breakfast or when you brush your teeth, and keep to it. If you take Cialis on demand, the long window means a tablet taken in the evening may still help the next morning.

Sources: Br J Clin Pharmacol (PMC) — Tadalafil pharmacokinetics in healthy subjects (Forgue et al., 2006); DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

How to take Cialis with food, alcohol and grapefruit

Food

Unlike sildenafil (Viagra), whose absorption can be delayed by a high-fat meal, you can take Cialis with or without food. The FDA label states that food does not affect the rate or extent of absorption, and the Forgue pharmacokinetic study found food had negligible effects on bioavailability. A heavy dinner is therefore not a reason to skip or move your dose.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; Br J Clin Pharmacol (PMC) — Tadalafil pharmacokinetics in healthy subjects (Forgue et al., 2006)

Alcohol

Both alcohol and tadalafil widen blood vessels. The label reports that substantial drinking, about 5 units or more, can increase orthostatic signs such as dizziness, a faster heart rate, headache and a drop in blood pressure when standing. The patient leaflet gives 5 glasses of wine or 5 shots of whiskey as an example of “too much.” The NHS adds that heavy drinking can itself make erections harder to get, so a drink or two is usually fine when you take Cialis, but a big night out works against the medicine.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; NHS — Tadalafil

Grapefruit and antacids

Grapefruit juice blocks the liver enzyme CYP3A4, which breaks tadalafil down. The label lists grapefruit juice among substances likely to increase tadalafil exposure, and the NHS advises not drinking it while you take Cialis. Antacids slow the rate of absorption a little but do not change the total amount absorbed.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; NHS — Tadalafil

Missed doses and taking too much

If you take Cialis on demand, there is no such thing as a missed dose: you simply take it before your next planned sexual activity. For daily Cialis, the advice from the FDA leaflet, MedlinePlus and the NHS is consistent:

• Take the missed tablet as soon as you remember.
• If your next dose is nearly due, skip the missed one and carry on as normal.
• Never take two tablets, or more than one dose in a day, to make up for a forgotten one.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; MedlinePlus — Tadalafil

If you take Cialis daily, missing one dose is rarely a problem in practice, because the drug builds up gradually: once-daily dosing reaches a steady blood level within about 5 days. Doubling up does not make erections better; it only raises the chance of headache, flushing, back pain and dizziness, which we cover in detail in our article on Cialis side effects.

Source: Br J Clin Pharmacol (PMC) — Tadalafil pharmacokinetics in healthy subjects (Forgue et al., 2006)

If you think you have taken more than your prescribed dose, contact a poison control center or emergency department straight away, and take the pack and any other medicines with you. Do not drive yourself if you feel dizzy.

Sources: Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH); NHS — Tadalafil

How to take Cialis with kidney or liver disease

Because the kidneys and liver clear tadalafil from the body, reduced function can leave more of the drug in your blood for longer. The FDA label therefore sets lower ceilings for some men who take Cialis. Age alone does not require a lower dose, although diarrhea was reported more often in men 65 and older.

Source: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

Your doctor works these limits out from blood tests and your medicine list, so tell them about any kidney or liver problem before you first take Cialis. Never adjust the dose yourself based on this table.

Medicines that change how you take Cialis

Never combine: nitrates, poppers and riociguat

Any nitrate, including nitroglycerin spray or tablets, isosorbide mononitrate or dinitrate, and recreational “poppers” (amyl or butyl nitrite), is contraindicated with Cialis because the combination can cause a dangerous fall in blood pressure. The same applies to guanylate cyclase stimulators such as riociguat, and Cleveland Clinic also lists vericiguat. If a man who has taken Cialis needs a nitrate in a life-threatening emergency, the label says at least 48 hours should pass after the last dose, which is why you should always tell emergency staff that you take Cialis.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH)

Lower the dose: CYP3A4 inhibitors

Tadalafil is mainly broken down in the liver by CYP3A4. Strong inhibitors of that enzyme, such as ketoconazole, itraconazole and the HIV medicine ritonavir, raise tadalafil levels; erythromycin and grapefruit juice probably do too. This is why the on-demand limit drops to 10 mg once every 72 hours and the daily limit to 2.5 mg. In the opposite direction, rifampin cut tadalafil exposure by 88% in a study, which can be expected to make the medicine less effective.

Source: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

Start low: alpha-blockers and blood pressure medicines

Alpha-blockers such as doxazosin, tamsulosin and alfuzosin also lower blood pressure. If you take one for ED, you should be stable on it first and start Cialis at the lowest dose. For BPH, the label does not recommend combining daily Cialis with an alpha-blocker, and it advises stopping the alpha-blocker at least one day before starting once-daily Cialis. Other blood pressure tablets, such as amlodipine, enalapril or metoprolol, caused only small additional drops in blood pressure in studies. Do not take Cialis with other ED tablets such as sildenafil, vardenafil or avanafil.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH)

If Cialis does not seem to work

Before deciding that tadalafil has failed, the EAU guidelines advise checking that the medicine has been prescribed properly and is being used correctly. Common problems are waiting too short or too long after the tablet, expecting an erection without sexual stimulation, and giving up after one or two attempts at a low dose. The EAU notes that patient education can rescue many apparent non-responders, and that after stressing dose, timing and stimulation, erectile function can often be restored when the same drug is tried again.

Source: EAU Guidelines — Management of Erectile Dysfunction

Practical steps include taking the tablet at least 30 minutes, and ideally an hour or two, before sex; allowing for foreplay; avoiding heavy drinking; and asking your doctor whether the dose can be raised within the label limits. Keep tablets in their original pack at room temperature, between 15°C and 30°C, away from the moisture of a bathroom. If correctly used tablets still do not work, there are other effective options, from penile injections for erectile dysfunction to implants.

Sources: Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH); MedlinePlus — Tadalafil

When to see a doctor

Only take Cialis after a medical assessment, because ED is often linked to diabetes, high blood pressure or heart disease, and because the drug is not safe for men for whom sexual activity is inadvisable because of their heart condition. Seek urgent medical help if you notice:

• An erection lasting more than 4 hours (priapism), whether painful or not.
• Sudden loss or decrease of vision in one or both eyes.
• Sudden decrease or loss of hearing, which may come with ringing in the ears (tinnitus) or dizziness.
• Chest pain, dizziness or nausea during sex: stop and get help right away.
• Signs of a severe allergic reaction, such as swelling of the lips, face or throat or trouble breathing.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; NHS — Tadalafil

You should also see a doctor if Cialis does not work after several correct attempts, if side effects bother you, or if you start any new medicine while you take Cialis. Men with heart disease can read more in our guide to erectile dysfunction and heart disease.

If you would like personal advice on how to take Cialis or on other options, you can have a confidential consultation with our urologist-andrologist on WhatsApp. The cost of any treatment depends on your assessment, and the first WhatsApp consultation is free.

FAQs about how to take Cialis

How long before sex should I take Cialis?

Take Cialis on demand at least 30 minutes before sex. Blood levels peak at a median of about 2 hours, so taking it an hour or two ahead often works better. Its effect can last up to 36 hours, which gives you a wide window and means you do not need to time sex precisely after the tablet.

Source: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

Can I take Cialis on an empty stomach or after a meal?

Either is fine. Food does not change how quickly or how much tadalafil is absorbed, so you can take Cialis before or after a meal, including a fatty one. This is a practical difference from sildenafil, which can be slowed down by a heavy meal. Swallow the tablet whole with water.

Sources: Br J Clin Pharmacol (PMC) — Tadalafil pharmacokinetics in healthy subjects (Forgue et al., 2006); NHS — Tadalafil

Can I drink alcohol with Cialis?

Small amounts are generally acceptable, but heavy drinking is not. About 5 units or more, roughly 5 glasses of wine, raises the risk of dizziness, headache, a fast heartbeat and low blood pressure when you stand up. Alcohol also weakens erections, which works against the medicine. Ask your doctor what is safe for you.

Sources: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information; MedlinePlus — Tadalafil

Can I take Cialis two days in a row?

Yes, if your doctor has prescribed it that way: daily Cialis is taken every day, and on-demand Cialis may be used up to once a day in most men. What you must not do is take more than one dose in a single day. Men with kidney disease or on certain medicines may be limited to one dose every 48 or 72 hours.

Source: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

Is it better to take Cialis in the morning or at night?

It makes little difference to how the drug is absorbed. Studies found that exposure was not substantially affected by the time of dosing. If you take Cialis daily, choose a time you will remember and keep to it. For on-demand use, take it at least 30 minutes before you expect to have sex.

Sources: Br J Clin Pharmacol (PMC) — Tadalafil pharmacokinetics in healthy subjects (Forgue et al., 2006); DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

What happens if I take two Cialis tablets by mistake?

Taking more than your prescribed dose raises the risk of side effects such as headache, flushing, dizziness and low blood pressure, and does not improve erections. Do not take any more that day, and contact a poison control center, your pharmacist or an emergency service for advice, bringing the pack with you if you go to hospital.

Sources: Cleveland Clinic — Tadalafil Tablets (Erectile Dysfunction, BPH); NHS — Tadalafil

Can I cut a Cialis tablet in half?

No. The FDA label states that Cialis tablets should not be split and that the entire dose should be taken, and the NHS advises swallowing tadalafil whole with water. If you need a lower dose, ask your doctor to prescribe a lower-strength tablet rather than cutting a larger one.

Sources: NHS — Tadalafil; DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information

Does Cialis work without arousal?

No. Tadalafil helps the natural erection process but does not start it. The FDA patient information states that some form of sexual stimulation is needed for an erection to happen. If you take Cialis and wait without any stimulation, it may seem as though it has not worked.

Source: DailyMed (FDA label) — CIALIS (tadalafil) tablets — prescribing information