Excessive alcohol drinking while you take Cialis may lead to some very serious side effects. In moderation, though, drinking alcohol likely won’t cause problems.

Cialis is used to treat erectile dysfunction, or difficulty getting or maintaining an erection. Generally, Cialis is a safe drug. However, you need to consider the other substances you take with it and the effects the combination can cause.

For example, alcohol and Cialis may interact. Here’s what to know to help you stay safe while taking Cialis.

Having just a glass of wine or other drink is unlikely to affect Cialis or cause any health risks. But if you take Cialis and drink excessively, you may be setting yourself up for some problems.

In particular, drinking too much alcohol while you take Cialis can lead to orthostatic hypotension. This can cause a headache, dizziness, and fainting, which can cause fractures or other injuries. Hypotension may also make your heart beat at a faster rate. In some cases, this can lead to severe heart problems.

This effect can occur because Cialis and alcohol both act as vasodilators. Vasodilators are substances that lower your blood pressure by relaxing the walls of your blood vessels, which allow the blood vessels to open wider.

Orthostatic hypotension can be even more likely with Cialis than with some other erectile dysfunction drugs. This may be because Cialis stays in your system longer than many other ED drugs.

Keep reading: List of drugs that treat ED »

What’s more, if you drink too much alcohol while you’re taking Cialis, stopping your drinking can lead to a sudden increase in your blood pressure level.

Moderate drinking is fewer than three alcoholic drinks per day. The amount in an alcoholic drink varies according to the type of alcohol. For example, one alcoholic drink could be:

  • 12 ounces of beer
  • 5 ounces of wine
  • 1.5 ounces of 80-proof liquor, such as gin, vodka, whisky, rum, or tequila

Consuming five or more drinks at a time while taking Cialis has been linked with orthostatic hypotension. That amount is a bit more than what is considered “moderate” drinking.

If you notice symptoms such as dizziness or headaches, stop drinking and tell your doctor.

If you regularly have three or more drinks per day or feel that you need to have a drink every day, talk with your doctor or a mental health counselor. Long-term excessive alcohol use is not only dangerous while you take Cialis, it also increases your risk of many health problems, including heart disease, obesity, and early dementia.

Cialis is a prescription medication, so before you start taking it, make sure your doctor knows your medical history and your current health status. That includes a list of all the medications you take. You should also be honest with your doctor about how much alcohol you drink on a regular basis.

Overall, moderate alcohol consumption while you take Cialis is usually safe. If you want to avoid potentially dangerous side effects, limit yourself to one or two drinks per day.