Cialis is a brand name version of tadalafil, a popular medication for treating erectile dysfunction (ED). Taking the medication properly helps you get the maximum effect while avoiding side effects.

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Reasons not to take 40 milligrams (mg) of Cialis include how the drug works and how long it lasts. Both can make it risky to up your dose.

If you feel your current dosage isn’t working, there may be options to consider. Let’s take a look at Cialis, why to avoid taking too much, and more.

It’s risky to increase your Cialis dose to 40 mg. Here’s why: The drug affects other parts of the body, which can cause unwanted side effects.

It changes more than your penis

While Cialis works for ED by affecting the PDE5 enzyme in the penis, it also effects other PDE enzymes in tissues and cells in other areas of the body. For example, PDE5 is found in tissues in the lungs, kidneys, liver, brain, and platelets.

Cialis also affects PDE11 which is found in tissues in the heart, pancreas, pituitary, skeletal muscles, testes, and corpus cavernosum.

It increases your chances of side effects

Doubling the maximum dose of Cialis to 40 mg can increase the chances of experiencing side effects including:

  • headaches
  • flushing
  • dizziness
  • back pain
  • vision and hearing changes

It may also cause priapism, an erection lasting longer than 4 hours, which can damage the penile tissue. If this occurs, an urgent medical evaluation is needed to prevent long-term damage.

It’s in your system a while and clears slowly

Another reason not to double your dose are the long-lasting effects of Cialis.

The effects of Cialis last much longer (up to 36 hours) compared to other PDE5 inhibitors like Viagra (4–5 hours). So, Cialis hangs around a while in your body and clears slowly. This can increase the risk of side effects if you add doses on top of what’s already in your system.

How does Cialis work?

Cialis is a phosphodiesterase type 5 (PDE5) inhibitor. It limits the effect of the PDE5 enzyme in the penis, allowing blood vessels in your penis to relax so blood can flow into the penis, helping to get or keep an erection. Keep in mind, Cialis won’t work unless you’re stimulated or aroused.

Healthline

Cialis, a brand name version of tadalafil, is available by prescription in tablet form in four different strengths:

  • 2.5 mg
  • 5 mg
  • 10 mg
  • 20 mg

The dose of Cialis for ED depends on your age and if you’re taking it once daily (lower dose) or as needed (higher dose).

According to the Food and Drug Administration (FDA) dosing guidelines for ED symptoms, the recommended dose for Cialis once daily is 2.5 mg to start and may be increased to 5 mg if needed.

The recommended dose for as-needed Cialis is 10 mg and may be adjusted up or down to a maximum of 20 mg.

What is the benefit of tadalafil?

Tadalafil is unique compared to other PDE5 inhibitors because it can be taken either once daily at a lower dose or as needed at least 30 minutes before sexual activity.

This lets you choose which dosing suits your lifestyle needs best.

Healthline

On average, Cialis starts to work in about 30 minutes, and can take up to 2 hours to take effect.

How well a medication works depends on the individual and can vary from person to person.

Don’t be discouraged if Cialis doesn’t work right away. If you’re nervous or anxious, this also affects your arousal and ability to get or keep an erection.

Talk to your doctor about your experience with Cialis to see if a dose increase or switching to a different ED medication would work better.

  • Try different timing if you take it as-needed. You may need to take Cialis a few times for you to figure out the best timing for as-needed dosing. Don’t take more than one dose in a day.
  • Be consistent for daily use. Some people prefer the daily dose because it allows small amounts of Cialis to always be in your bloodstream, so you can have flexibility with sexual activity. For the daily dose, try to take it at the same time every day.

Cialis can last up to 36 hours in the body, but may last up to 72 hours in some cases. How long it lasts can vary.

Your age, genetics, and if you have heart, liver, or kidney disease all affect how the drug works and how long Cialis stays in your body. You may need dose adjustments to avoid side effects.

The dosage of Cialis and how it’s prescribed for you depends on:

  • your overall health
  • your age and lifestyle
  • other medications you’re taking
  • other conditions you may have like diabetes or high blood pressure

If you have heart, kidney, or liver disease, it’s important to discuss your ED treatment options with a doctor. You may need a lower dose of Cialis to avoid side effects.

Warning

Do not take Cialis with nitrate class angina medications or alpha blocker medications. They can cause a dangerous drop in your blood pressure.

Some tips when taking Cialis:

  • avoid excess alcohol because it can cause low blood pressure, dizziness, and fainting
  • avoid grapefruit juice with Cialis, as it interacts with the medication
  • take the medicine as prescribed by your doctor
  • ask your pharmacist about interactions with other medications

Lifestyle tips to improve ED symptoms:

  • try to lower stress and anxiety
  • increase your physical activity and eat a healthy diet
  • communicate with your partner about your concerns
  • consider professional counseling or sex therapy

Upping your dose of Cialis increases your chances of serious side effects and damage.

Serious side effects may include:

  • low blood pressure (a higher dose may increase risk of dizziness and fainting)
  • chest pain
  • confusion
  • difficulty speaking or breathing
  • priapism (a higher dose may increase this risk due to the longer effect of Cialis)
  • sudden change or loss of vision or hearing

Call your doctor if you feel you’re experiencing serious side effects. Get medical help right away if you experience an erection lasting longer than 4 hours.

Some common side effects for Cialis include:

  • muscle pain and back pain (higher doses may increase risk of these effects)
  • limb pain
  • headache
  • diarrhea
  • dizziness
  • indigestion
  • flushing
  • stuffy or runny nose
Allergic reaction

If you feel you’re experiencing an allergic reaction to Cialis (face or tongue swelling, rash, difficulty breathing or swallowing) or a medical emergency, seek immediate medical attention or call 911.

Cialis is one of the most popular ED medications sold worldwide. Unfortunately, it’s also very common to find Cialis and other ED medications sold online without a prescription through fake pharmacies and on other risky online portals.

Buying prescription medications online through fake sites can not only jeopardize your health but may also compromise your data and privacy.

These fake products are designed to look exactly like the genuine prescription but may be tainted, have more or less than the listed strength or dose, be expired, have harmful ingredients, and pose a serious risk to your health.

Keep in mind, you can’t tell what’s in these products just by looking.

So, what can you do?

The best way to learn more about ED is to make an appointment with a doctor. They can diagnose the problem and offer a prescription if that’s needed.

Telehealth options, (sometimes covered by insurance, including Medicare plans) such as over the phone, online services, and telemedicine apps are available to connect you with a doctor.

If the Cialis dose your doctor prescribed doesn’t seem to be helping, don’t double your dose to 40 mg on your own. This could increase the risks of serious adverse reactions or side effects.

Make an appointment to talk to your doctor about possible causes and alternative treatment options including other PDE5 inhibitors, other medications, and lifestyle changes that might help.

It’s important to discuss your sexual history, medications you’re taking, and your overall health and concerns about ED with a doctor.