Tadalafil With Alcohol: How Much Is Too Much?

The Cialis label's five-unit line, the studies behind it, and why a long half-life matters on daily doses.

Tadalafil can be taken with a normal amount of alcohol for most healthy men, but heavy drinking with it raises the chance of dizziness, headache, a fast heartbeat and a drop in blood pressure. The Cialis label draws the line at about five units of alcohol at once, and the patient leaflet gives the example of five glasses of wine or five shots of whiskey.¹ MedlinePlus gives the same five-glass example and tells patients to talk to their doctor about alcohol during treatment.²

What does the Cialis label say about tadalafil and alcohol?

The label explains the interaction in one idea: alcohol and tadalafil are both mild vasodilators, so when they are combined, the blood-pressure-lowering effect of each can add to the other.¹ The label says that substantial alcohol consumption (for example five units or more) with tadalafil can increase the chance of orthostatic signs and symptoms, which means a faster heart rate, a fall in standing blood pressure, dizziness and headache.¹

The same label reports that tadalafil did not change alcohol levels in the blood and alcohol did not change tadalafil levels.¹ So this is an effect on blood vessels and blood pressure, not one drug changing how the body clears the other.

What did the alcohol studies find?

The label summarises three clinical pharmacology studies. The two larger-dose studies gave alcohol at 0.7 g/kg, which the label equates to about 6 ounces of 80-proof vodka in an 80 kg man, swallowed within 10 minutes, together with tadalafil 10 mg in one study and 20 mg in the other. In both, more men had clinically significant blood pressure drops on the combination than on alcohol alone, and some reported dizziness on standing and orthostatic hypotension.¹

When tadalafil 20 mg was given with a lower dose of alcohol (0.6 g/kg, about 4 ounces of 80-proof vodka, again within 10 minutes), the label says orthostatic hypotension was not seen, dizziness was about as frequent as with alcohol alone, and alcohol's blood-pressure effect was not increased.¹

These were controlled studies in volunteers, with a large dose of alcohol drunk quickly. They show a dose pattern, not a safe number for any one person, and they do not cover men on blood pressure medicines or with heart disease.

Does daily tadalafil change the advice on alcohol?

Possibly in practice, though the label does not set a different alcohol limit. Tadalafil has a mean terminal half-life of 17.5 hours in healthy men, so after a dose it stays in the body long after the evening has ended.¹ The label tells prescribers to keep this continuous presence in mind when they consider interactions with nitrates, alpha-blockers, blood pressure medicines, strong CYP3A4 inhibitors and substantial alcohol, especially for once-daily use.¹ In plain terms, a man on a 2.5 mg or 5 mg daily dose has tadalafil on board whenever he drinks, not only on the nights he planned for.¹ Our tadalafil doses guide covers daily use in detail, so the practical point here is simply this: ask the prescriber how much alcohol is reasonable with the dose you take.

Does alcohol itself affect erections?

Separately from the drug interaction, the research on drinking and erectile dysfunction (ED) is mixed. A 2018 dose-response meta-analysis of 24 cross-sectional studies (154,295 men) found that light to moderate drinking (under 21 drinks a week) was linked to lower odds of ED (odds ratio 0.71), while regular and high drinking showed no significant difference.³ A 2021 meta-analysis of 46 studies (216,461 participants) described a J-shaped relationship, and its authors suggested that chronic drinking could cause vascular damage.⁴

These are observational studies, so they cannot show that a small amount of alcohol protects erections.

Who should be more careful?

The label bars tadalafil in anyone taking nitrates in any form, and it cautions on alpha-blockers and antihypertensive medicines, which also lower blood pressure.¹ Alcohol adds a third source of lowering. Men with low resting blood pressure, a history of fainting, heart conditions, or liver problems should ask before combining the two. The label recommends against use of Cialis in severe hepatic impairment because of insufficient information.¹ For the wider interaction picture see ED medication interactions and does tadalafil lower blood pressure.

Practical points that follow from the label

• Keep alcohol well under five units in a sitting while taking tadalafil, and lower if you are dizzy on standing after a single drink.¹
• Stand up slowly after drinking on a dose day; the labeled effect is a fall in standing blood pressure.¹
• Do not take extra tablets to make up for a drink. See tadalafil side effects for what the headache, flushing and dizziness can look like.
• Seek emergency care for chest pain, an erection lasting more than four hours, or sudden vision or hearing loss.¹

Limits of what we know

Every number above comes from short studies in volunteers who drank on a schedule, and from one manufacturer's label. Nothing here tells a particular man how many drinks are right for him, and none of it covers heavy alcohol use or alcohol-related liver disease, where a prescriber's judgement is needed. If you are choosing between tadalafil and another drug for how it behaves around drinking, see our comparison, sildenafil or tadalafil.

Questions readers ask

Can you drink alcohol while taking tadalafil?

The Cialis label does not ban alcohol. It warns that substantial consumption, for example five units or more, can increase dizziness, headache, a faster heart rate and a fall in standing blood pressure. Ask the prescriber what is reasonable for your dose and health.

How long after taking tadalafil can you drink?

The label gives no waiting time. Tadalafil has a mean terminal half-life of 17.5 hours, so it remains in the body for a day or more, and the caution applies to the amount of alcohol rather than the gap between the dose and the drink.

Can alcohol make tadalafil less effective?

The label reports that alcohol did not change tadalafil blood levels. What drinking does to an erection is a separate question, and heavy intake can interfere with erections in its own right.

Is tadalafil with alcohol dangerous?

In the studies the label describes, the main finding was lower blood pressure and dizziness with large doses of alcohol. Risk rises with nitrates, alpha-blockers, blood pressure medicines and heart conditions, so those need a prescriber's advice.

Does daily tadalafil mix differently with alcohol than as-needed tadalafil?

The label sets no separate alcohol limit for daily use, but it asks prescribers to remember that the drug is continuously present when assessing interactions with substantial alcohol.

Further reading

Part of our guide: How ED Medications Work: Timing, Food, Interactions and Combinations

• Sildenafil Headache: How Common Is It?
• What Is Tadalafil Used For? The Three Approved Uses
• Tadalafil Brand Names: Which Brand Is Used for What
• Sildenafil or Tadalafil: How the Two Drugs Differ