Tadalafil is a medication commonly prescribed for erectile dysfunction. It’s available in several different dosage strengths and two different dosing regimens, so you’re likely to find something that works for you and your lifestyle. In this guide, we’ll take a closer look at the dosage options, how to know how much you should be taking, and offer advice on how to get the most out of your treatment.
As always, the content in this article is for educational purposes only. It’s important to stick with the dosing instructions given to you by your prescribing doctor and to not change your dose without discussing this with a healthcare provider.
What is tadalafil (generic Cialis®)
Tadalafil, which you probably recognize by its brand name, Cialis®, is the generic version of a type of medication called a phosphodiesterase 5-inhibitor (PDE5i). It’s a popular FDA-approved treatment for erectile dysfunction but is also approved to treat two other conditions: benign prostatic hyperplasia (an enlarged prostate) and pulmonary arterial hypertension (high blood pressure affecting the arteries in the lungs). It’s usually taken as an oral tablet.
How does tadalafil work?
Tadalafil works by blocking the effects of the enzyme phosphodiesterase 5 (PDE-5), which is commonly found in the blood vessels in the penis, prostate and lungs. Normally, PDE-5 helps break down a molecule involved in dilating (expanding) blood vessels. By allowing this molecule to stay intact longer, blood vessels stay widened, increasing blood flow to the penis.
What are the dosage options for tadalafil?
The starting and maximum dosage strengths of tadalafil for erectile dysfunction depend on whether you’re taking it as needed (on demand) or daily, and other factors such as age and whether you have pre-existing liver or kidney disease. That’s because these conditions can affect how drugs are broken down and eliminated from the body.
The tadalafil dosage for erectile dysfunction ranges from 2.5-20 mg. When taken as on demand, the typical starting dose for tadalafil is 10 mg, which can be increased to 20 mg depending on the patient’s needs. The tadalafil dosage if you’re taking it daily is typically 2.5 mg, which can be increased to a 5 mg maintenance dose.
Can you take too much tadalafil? Yes. For patients taking this medication on demand, it’s not recommended to exceed 20 mg in 24 hours. Taking too much of any medication can increase the risk of side effects due to increased drug exposure and it’s extra important to keep this in mind for longer-acting drugs like tadalafil. It’s one of the reasons why the daily maintenance dose is smaller than the as needed dosage option. Studies show that these smaller daily dosages of tadalafil are enough to establish stable blood levels of the medication after just 5 days (Forgue et al., 2005).
Timing and duration for tadalafil
Compared to sildenafil (generic Viagra®), tadalafil is a longer lasting medication with a half-life of 17.5 hours compared to sildenafil’s 4-5 hours. This means that the effects of a single dose of tadalafil can last up to 36 hours (Washington and Shindel, 2010). Another big difference is that while sildenafil is taken as needed, tadalafil can be prescribed for on demand use or as a daily medication. When taken on demand, both tadalafil and sildenafil should be taken at least 30 minutes to an hour before engaging in sexual intercourse. The daily dosing option for tadalafil has the added benefit of helping you be ready whenever you want to.
Is taking a higher dose of tadalafil more effective?
This is a great question. In general, there aren’t significant differences in efficacy between the daily or on demand dosing regimens for tadalafil. In one large multicenter trial, men were treated with 20 mg three times a week or 20 mg on demand over a 12-week period. More than 60% of men in either treatment group reported normalization of erectile function and more than 70% in both groups also reported being able to have sexual intercourse successfully compared to baseline. There is some data that suggests there may be differences between the on demand and daily dosing schedules (with daily dosing coming out on top) when it comes to other dimensions of sexual experience (e.g., satisfaction with sex, whether confidence improves). For patients taking tadalafil daily, this could be due to added flexibility around the timing of sexual activity (Brock et al., 2017).
When it comes to absolute dosage differences, for example taking 10 mg of tadalafil versus taking 20 mg, there does appear to be a dose-dependent response. According to one Japanese study, men with severe erectile dysfunction who took the larger 20 mg dose experienced greater improvements in erectile function (Marumo et al., 2007). The safety and tolerability of these dosage options are similar.
Why isn't my tadalafil dosage working?
If you have any concerns about whether the medication you’re taking is doing what it’s supposed to, we highly recommend talking to your prescribing physician. Based on the data from the section above, in some cases, increasing your dosage of tadalafil could make it more effective (make sure you talk to your prescribing doctor about this) but there are three other key points to consider:
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Not taking tadalafil at the right time
If you’ve been prescribed tadalafil to use on demand as needed, it’s important to remember to take it at least 30 minutes to an hour before having sex. Also note that you need to be sexually excited for tadalafil to work. It doesn’t cause spontaneous erections.
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Mixing tadalafil with alcohol
There's no science to support the idea that drinking makes tadalafil (or any other PDE5i) more effective. Alcohol might take the edge off the anticipation of a sexual encounter, and there may be a narrow range of intake that could enhance its effects on blood vessels, but this sweet spot hasn’t been identified. In fact, drinking too much could affect your ability to maintain an erection, independent of whether you’re taking tadalafil. You can check out our blog article on alcohol and erectile dysfunction to learn more.
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Overlooking the importance of lifestyle
On a physiological level, erections depend on a healthy, functioning cardiovascular system. Exercising regularly and making smart food choices have always been recommended by health professionals as preventative strategies against heart disease, and the benefits extend to your sex life. We’ve written a whole article on the relationship between high blood pressure and erectile dysfunction and why it’s important in some cases to take a step back and consider whether a problem in one area of your body might indicate something bigger that needs attention.
Side effects and safety warnings for tadalafil
Tadalafil has been associated with side effects such as headaches, dyspepsia (indigestion), back pain and muscle aches, flushing and nasal congestion. The exact mechanisms behind these side effects are still being determined but could have something to do with tadalafil’s effects on blood vessels and smooth muscle tissue. There are several rarer but serious side effects of tadalafil that have been reported, including: hypotension (low blood pressure), vision changes and hearing loss (which can become permanent) and priapism, or an erection that lasts more than 4 hours. These serious side effects require prompt medical attention to avoid permanent injury.
Taking too much tadalafil can increase your chances of experiencing side effects, which is why it’s so important to follow dosage instructions and only take tadalafil with medical supervision.
Tadalafil dosage guide: key rules
Medications like tadalafil come in different dosages to help meet the lifestyle preferences and needs of patients. Tadalafil is typically prescribed at a starting dose of 10 mg taken as needed, or 2.5 mg taken once daily. These dosages can be increased to 20 mg or 5 mg respectively.
It's essential that you don't take more than 20 mg of tadalafil within a 24-hour period (doing so could put you at an increased risk for side effects) and remember that for tadalafil to work, you need to be sexually excited or aroused. Finally, tadalafil should only be taken under the supervision of a doctor or another trusted healthcare professional.
References:
Brock, G., Ni, X., Oelke, M., Mulhall, J., Rosenberg, M., Seftel, A., D'Souza, D., & Barry, J. (2016). Efficacy of Continuous Dosing of Tadalafil Once Daily vs Tadalafil On Demand in Clinical Subgroups of Men with Erectile Dysfunction: A Descriptive Comparison Using the Integrated Tadalafil Databases. The Journal of Sexual Medicine, 13(5), 860–875. https://doi.org/10.1016/j.jsxm.2016.02.171
Forgue, S. T., Patterson, B. E., Bedding, A. W., Payne, C. D., Phillips, D. L., Wrishko, R. E., & Mitchell, M. I. (2006). Tadalafil pharmacokinetics in healthy subjects. British Journal of Clinical Pharmacology, 61(3), 280–288. https://doi.org/10.1111/j.1365-2125.2005.02553.x
Marumo, K., Imaoka, T., Fujimoto, K., Watts, S., Stothard, D., & McGill, J. (2007). A comparison of the efficacy and tolerability of tadalafil 10 mg and 20 mg in Japanese patients with severe erectile dysfunction. The Journal of Sexual Medicine, 4(3), 745–752. https://doi.org/10.1111/j.1743-6109.2006.00387.x
Washington, S. L., 3rd, & Shindel, A. W. (2010). A once-daily dose of tadalafil for erectile dysfunction: compliance and efficacy. Drug Design, Development and Therapy, 4, 159–171. https://doi.org/10.2147/dddt.s9067
