How to take Cialis for ED

In this article:

• What is Cialis, and how does it work?
• Cialis directions explained
• Cialis daily vs. as-needed: Which to choose
• How long does Cialis last?
• Cialis side effects and warnings
• Tips for taking Cialis
• Common Cialis questions and answers

In this article

• What is Cialis, and how does it work?
• Cialis directions explained
• Cialis daily vs. as-needed: Which to choose
• How long does Cialis last?
• Cialis side effects and warnings
• Tips for taking Cialis
• Common Cialis questions and answers

Some prescription medications offer a lot of flexibility in timing and dosing, allowing you to fit them easily into your existing routine. But other drugs need to be taken in specific ways in order to provide the effects or benefits you’re hoping for. Cialis (tadalafil) is one of these drugs. Approved to treat erectile dysfunction (ED) in men, Cialis can be very effective when taken the correct way. But if you’re new to this medication, you may be wondering what that “correct” way is: When should you take it, what should you take it with, and what can you expect after you do? Here’s what to know about when and how to use Cialis.

What is Cialis, and how does it work?

Cialis is a type of medication called a phosphodiesterase type 5 (PDE5) inhibitor. This means it blocks the PDE5 enzyme, which normally prevents muscles—including those in blood vessels—from relaxing. In addition to ED, Cialis is also approved to treat benign prostatic hyperplasia (BPH), or an enlarged prostate.

By allowing the muscles to relax, Cialis enhances the body’s natural response during sexual arousal, allowing for the increased blood flow needed to enlarge the penis and create an erection, according to Roshni Patel, MD, internal medicine provider at Executive Medicine of Texas.

It’s important to note that Cialis doesn’t automatically cause an erection, but makes it easier for you to get and maintain one with arousal. In other words, some kind of stimulation is still needed for Cialis to work.

RELATED: How much does Cialis cost without insurance?

Cialis directions explained  

Cialis is available in several doses: 2.5 milligrams, 5 milligrams, 10 milligrams, and 20 milligrams. Not all of these doses are appropriate for all of the reasons Cialis is prescribed, however.

For daily use for ED, Dr. Patel says most people start with the smallest dose, 2.5 milligrams (mg), and can choose to increase their dose to 5 mg—under the guidance of their healthcare provider—depending on how they respond to it. This daily dose should be taken at the same time each day, regardless of sexual activity. If you are taking Cialis daily for BPH—or for both ED and BPH—the typical daily dose is 5 mg once daily.

If you are taking Cialis as needed, your provider may allow you to take 10 milligrams as a single dose, although some people require higher doses after a trial period. Dr. Patel says this dose should be taken at least 30 minutes before participating in sexual activity. 

Whatever type of Cialis dosing you’re on, Dr. Patel says you should never take more than one of your prescribed tablets per day. In other words, if you take a daily dose in the morning, you should not take another dose later that day before sexual activity.

You should take Cialis with a glass of water, and avoid excessive alcohol. Combining Cialis with excessive amounts of alcohol can increase your risk for blood pressure-related side effects, like headache and dizziness. 

Cialis daily vs. as-needed: Which to choose

If your healthcare provider gives you a choice between daily or as-needed Cialis, you may be wondering which one to choose. 

Dr. Patel says as-needed Cialis is better for men who have less frequent sexual activity and no other related health conditions, while daily Cialis is a good choice for men who have sex regularly or who also have BPH: “Once-daily Cialis can treat both conditions simultaneously, [which] is often a win-win for many of my patients,” he says.

You may also want to think about how easy it is for you to plan for sexual activity, according to Dr. Patel, since daily Cialis dosing allows for spontaneous intimacy without having to worry about timing your medication beforehand.

How long does Cialis last?

Experts recommend taking Cialis at least 30 minutes before sexual activity because it can take some time to begin working. Studies show the effects usually peak around two hours after you first take the medication, so try not to expect instant results (or become frustrated or anxious if the drug doesn’t seem to be working yet), because that can interfere with your ability to be aroused.

In fact, you have a relatively long window of time to expect the effects of Cialis to last—about 24 to 36 hours, in many cases. That’s why Cialis is sometimes called the “weekend pill.” You could take it on a Friday evening and still find it easier to become aroused until late Saturday evening or even Sunday morning.

Exactly how long it takes Cialis to begin working and to wear off depends on a few factors. According to Dana Manning, Pharm.D., RD, LDN, associate professor of pharmacy practice at Wilkes University in Pennsylvania, some things that may slow down or speed up how quickly your body metabolizes this medication include:

• Food and drinks: Grapefruit and grapefruit juice can interact with Cialis and cause side effects, such as low blood pressure and priapism (an erection that lasts longer than four hours and/or is very painful). Experts recommend avoiding foods and beverages that contain grapefruit when taking Cialis. You should also limit alcohol while taking Cialis, as the combination can increase the risk for low blood pressure, headache, and dizziness. If you drink alcohol, it’s a good idea to discuss safe amounts with your healthcare provider. 
• Other medications: Cialis is metabolized by an enzyme in your liver called CYP3A4, so if you take it with certain other medications metabolized by the same enzyme, it may affect how much medication is absorbed. One example, according to Dr. Manning, is the antifungal medication fluconazole, though there are other medications that interact, too. Be sure to check for drug interactions with your healthcare provider before using Cialis.
• Age: Older adults may have slower metabolisms, so they may find that it takes longer for Cialis to start working and that it lasts a little longer. This can also increase the risk of side effects, so lower doses are sometimes prescribed in older adults.

Cialis side effects and warnings

While Cialis is generally considered safe for men with ED, it does include some risk of side effects. Common side effects of Cialis include headache, muscle pain, dizziness, and flushing. More serious side effects include changes to vision or hearing and painful erections lasting more than six hours.  

Another possible side effect to watch out for is low blood pressure, according to Joyce Oen-Hsiao, MD, associate professor of medicine at Yale School of Medicine, especially if you’re taking nitrates to treat chest pain or blood pressure medications like alpha blockers. There are several other medications that may interact with Cialis, too, so make sure you tell your healthcare provider your full medical history, including all prescription and over-the-counter drugs you regularly take. Some drugs, like nitrates, should never be taken with Cialis—while others may require caution or dosage adjustments. 

Finally, Dr. Oen-Hsiao says people with liver impairment should only take Cialis as needed (not daily), and at a maximum dose of 10 milligrams.

Tips for taking Cialis

When prescribed by your healthcare provider and taken as directed, Cialis is considered a safe and effective treatment for ED. If you have any questions about how or when to take Cialis, don’t hesitate to talk to your healthcare provider for guidance tailored to your specific concerns or overall health. 

In the meantime, here are some tips for getting the most out of your ED medication:

• Take it at least 30 minutes before sexual activity.
• Be patient if it doesn’t work right away—the effects often peak about two hours after you take a dose.
• Remember that Cialis doesn’t cause an erection automatically; you still need to become sexually aroused for it to work.
• Also remember that Cialis can make it easier for you to be aroused for up to 36 hours after taking it, so you have a long window of time to take advantage of the drug’s effects.
• Talk to your provider about adjusting your dose if it doesn’t seem to be working well enough for you.
• Consider asking your provider about switching from an as-needed dose to a daily dose (or vice versa) if your current dosing isn’t working with your lifestyle or routine.
• Take Cialis with plenty of water to make sure it absorbs correctly in your body.
• Avoid taking it with an excessive amount of alcohol.

Common Cialis questions and answers

Can I get Cialis without a prescription?

No, Cialis is available by prescription only and can’t be purchased over the counter.

Can I combine Cialis with other ED drugs?

Medications for ED generally all block the PDE5 enzyme, so it’s not recommended to combine them, due to the increased risk of serious side effects.

Who shouldn’t take Cialis?

People with existing heart conditions, severe liver disease, or certain retinal eye problems should not take Cialis. People taking certain other prescription medications, including nitrates, guanylate cyclase (GC) stimulators, and alpha blockers, are also usually told to avoid Cialis because of an increased risk of serious side effects, including dangerous low blood pressure. Talk to your healthcare provider about whether Cialis is safe for you.