Drug Interactions, Kratom Guides

Mixing Tadalafil (Cialis) & Kratom: Here’s What The Science Says

Given the fact that kratom is only just now starting to be known in the United States, it’s likely that many kratom users do not know that it has certain characteristics that make it likely to react with many compounds.

And — as it turns out — tadalafil (Cialis) is one of those compounds. 

There is always a risk when using a new drug combination, and kratom is no exception.

Find out more about the interaction between kratom and tadalafil.

Last updated 5 months ago by Wade Paul

Mixing Tadalafil (Cialis) & Kratom: Here’s What The Science Says

Does Kratom Interact With Tadalafil (Cialis)?

Yes, there is a moderate interaction between kratom and PDE5 inhibitors like tadalafil. 

The CYP3A4 enzyme mainly metabolizes tadalafil. As a CYP3A4 inhibitor, kratom can lessen the efficiency of tadalafil’s metabolization and cause increased levels of the drug, leading to adverse effects [1, 2]. 

You need to talk to your doctor about whether or not this will cause serious complications for you.

Tadalafil Specs

Drug Name Tadalafil
Trade NamesCialis, Cidala, Adcirca
Classification PED5 Inhibitor
CYP MetabolismCYP3A4
Interaction With Kratom Metabolic
Risk of InteractionModerate

Is it Safe to Take Kratom With Tadalafil?

Possibly, but not necessarily. How’s that for vague? Really, though, the metabolic interaction between these two compounds will always imply a certain level of risk. Chances are, there won’t be significant complications from using them together, especially if they’re not used often. Still, only your doctor knows whether the risk is minimal or not.

The unique pharmacological properties of tadalafil — mainly its extended half-life — also mean that the risk is even more pronounced since the compound takes longer to be cleared from the body. 

However, a combination of tadalafil and kratom does not necessarily mean there will be a serious interaction, only that the risk of adverse effects is greater.

What is Tadalafil (Cialis)?

Tadalafil is a prescription medication classified as a phosphodiesterase type 5 inhibitor (PDE5 inhibitor).

PED5 inhibitors work by blocking the PDE5 enzyme and preventing it from functioning. The effect of this inhibition is to relax blood vessels and increase blood flow to various tissues. 

These properties are used to treat several different conditions, although PDE5 inhibitors are most commonly used for erectile dysfunction (ED).

What is Tadalafil Used for?

Tadalafil is different from other similar-use PDE5 inhibitors because of its extended half-life (17.5 hours). It’s even called “the weekend pill” due to this long duration. The half-life of vardenafil (Levitra) and sildenafil (Viagra) is around 5 hours.

Tadalafil is FDA-approved for the following treatments:

  • Erectile disfunction
  • Symptoms of benign prostatic hyperplasia (BPH)

In general, the scientific literature demonstrates how tadalafil is just as safe and effective as other PDE5 inhibitors [3].

What’s the Dose of Tadalafil?

Tadalafil is available in 2.5, 5, 10, and 20 mg tablets.

The starting dose is 10 mg 1 hour before sexual activity. Depending on efficacy and tolerability, the dose may be increased to 20 g or decreased to 5 g. 

While tadalafil is most often taken on demand, it can also be used daily. For this, the dose should be between 2.5 and 5 mg. 

Taladafil may be taken without food.

Always remember that tadalafil is a prescription medication. A licensed doctor must conduct a risk assessment to determine if tadalafil is right for you. 

Generic & Brand Name Versions

Taladafil is available under the following brand names:

  • Cialis
  • Cidala
  • Adcirca

What Are the Side Effects of Tadalafil?

Taladafil has a profile of adverse effects much like other PDE5 inhibitors.

The most common side effects include [4]:

  • Headache
  • Stomachal discomfort
  • Indigestion
  • Burping
  • Acid reflux
  • Back pain
  • Muscle Aches
  • Flushing

More serious adverse effects include:

  • Hypotension
  • Priapism
  • Loss of hearing
  • Loss of vision
  • Heart attack

Contraindications to taking tadalafil include:

  • Hepatic impairment
  • Renal impairment
  • Administration with nitrates and nitric oxide donors
  • Concomitant use of alpha-blockers, antihypertensives, and acute amounts of alcohol
  • Cardiovascular issues

What is Kratom?

The kratom plant is a species indigenous to Southeast Asia. It’s also known by its scientific name: Mitragyna speciosa.

The leaves of the kratom plant are harvested by local farmers and ground down to make a powder — this is what we call kratom.

Kratom possesses potent psychoactive and pharmacological properties due to its powerful alkaloids. There are more than just two, but kratom’s effects come mostly from mitragynine and 7-hydroxymitragynine

Kratom behaves very much like an opioid, which is partly why it’s so popular — it’s also why some states ban it. As such, kratom can be addictive. However — and this is crucial — it’s not likely to cause an overdose and is not dangerous on its own. 

Suggested Reading: The WHO’s Decision on the Kratom Ban

What is Kratom Used for?

Kratom has many properties and thus has various uses:

What’s the Dose of Kratom?

The effects of kratom are dose-dependent the amount you take impacts the results you get.

Common dosing amounts are as follows:

  • Low dose (1 – 5 g): Energizing; produces nootropic and stimulating effects such as increased focus, creativity, and euphoria. 
  • Medium dose (5 – 10 g): Relaxing and calming; provides pain relief and reduces anxiety.
  • High dose (10 – 15 g): Sedating; these amounts are best for intense pain or withdrawal.

Still not sure? Here’s a dosing guide and calculator to help you dial it in.

If you’re just starting out with kratom, keep it under 5 g. Learn how your body reacts with kratom before you experiment with higher doses. 

What Are the Side Effects of Kratom?

Kratom is safe, and most people don’t have any issues with it. But, life isn’t perfect, and nothing is 100% safe. Kratom has side effects, but they’re usually not serious especially when compared to many (most) prescription medications.

Here are kratom’s most common side effects:

  • Constipation
  • Dizziness
  • Insomnia
  • Nausea
  • Itchiness

The following are less common but more serious:

  • Loss of muscle coordination
  • Low blood pressure
  • Low libido
  • Nausea
  • Poor appetite
  • Seizures
  • Tremors

Luckily, these side effects are usually quite mild and are easily controlled by scaling back consumption.

What Are the Different Types of Kratom?

The first thing you might notice about kratom is its different strain. There are three main strains, with a fourth that likes to tag along. 

Each strain possesses the ability to reduce pain, provide energy, or knock you out; however, each strain also contains different alkaloid levels, impacting how it’ll affect you physically.

A) White Vein Kratom

The white strains excel at producing energy, improved mood, and focus. Tired of relying on coffee? Try one of these strains. 

B) Red Vein Kratom

Red strains are the “pharmacological strains” great for pain, anxiety, and sleep. Whether you need help relaxing at the end of the day or dealing with chronic pain, these strains are the ones to reach for.

C) Green Vein Kratom

Green strains don’t offer focused benefits; instead, they offer the whole package. You can’t expect mind-blowing pain relief or energy, but you’ll get a little bit of everything. Of course, some are better one way or the other, so read descriptions before settling on one. 

If you’re interested in experimenting with everything that kratom offers, try a green-veined strain.

D) Yellow Vein Kratom

There’s not much that stands out with yellow strains, but they tend to be milder. They’re similar to green strains due to their overall balanced effects. 

Many prefer it for these exact reasons, especially those with a proven sensitivity to kratom.

Key Takeaways: Is it Safe to Mix Kratom & Tadalafil (Cialis)?

Not quite. Similar to other PDE5 inhibitors, kratom has an inhibitory effect on tadalafil’s metabolization. This increases the risk of adverse effects.

And yes, you might be able to use them together safely, but tadalafil has an extra complicating factor that other PED5 inhibitors do not have it’s known for its unusually long half-life. This particular feature of tadalafil makes it riskier to mix with kratom.

If you want to use them together, speak to your doctor first to make sure you won’t face adverse effects.


  1. Hanapi, N. A., Ismail, S., & Mansor, S. M. (2013). Inhibitory effect of mitragynine on human cytochrome P450 enzyme activities. Pharmacognosy research, 5(4), 241.
  2. Huang, S. A., & Lie, J. D. (2013). Phosphodiesterase-5 (PDE5) inhibitors in the management of erectile dysfunction. Pharmacy and Therapeutics, 38(7), 407.
  3. Carson, C. C., Rajfer, J., Eardley, I., Carrier, S., Denne, J. S., Walker, D. J., … & Cordell, W. H. (2004). The efficacy and safety of tadalafil: an update. BJU international, 93(9), 1276-1281.
  4. Rajfer, J., Aliotta, P. J., Steidle, C. P., Fitch, W. 3., Zhao, Y., & Yu, A. (2007). Tadalafil dosed once a day in men with erectile dysfunction: a randomized, double-blind, placebo-controlled study in the US. International journal of impotence research, 19(1), 95-103.