The side effects of tadalafil resemble those of other ED medications, with one difference: back pain and muscle pain occur more often. Headache, flushing and a blocked nose top the list. Because tadalafil stays active for up to about 36 hours, those complaints can also last longer.
Tadalafil is known by the brand name Cialis. It is the only ED medication in the Netherlands also prescribed for urinary complaints caused by an enlarged prostate.
That double role is the most interesting thing about this medicine, and it is exactly what most articles leave out.
How long does tadalafil actually work?
Tadalafil starts working after roughly 30 to 120 minutes and then stays active for up to about 36 hours. That comes from its half-life of around 17.5 hours, far longer than the roughly 4 hours of sildenafil. Hence the nickname weekend pill.
An important detail: those 36 hours do not mean 36 hours of erection. They mean the medicine can help during that window when sexual stimulation is there.
A fatty meal barely affects absorption with tadalafil. In practice that matters more than you would think, because a dinner does not have to disrupt the timing.
Daily or only when needed?
Tadalafil comes in two regimens, and the distinction shapes both the effect and the side effects. The low daily dose keeps levels constant, the higher dose is taken per occasion. Which form is appropriate is your doctor's call.
| Regimen | Strength | How taken | Often used for | Watch out for |
|---|---|---|---|---|
| Daily | 2.5 or 5 mg | Every day, fixed moment | Frequent sex, or urinary complaints from prostate enlargement | Complaints can be continuously present |
| On demand | 10 or 20 mg | About 30 minutes beforehand | Less frequent sex | Effect and complaints can last a day |
These strengths come from the patient leaflet and the Dutch Farmacotherapeutisch Kompas. They are descriptive here, not advice.
Take two men both using tadalafil. One takes 5 mg daily and notices after two weeks that his urine flow improves as well, because his prostate benefits too. The other takes 20 mg on demand and has back pain for two days after a single tablet.
Same medicine, different dose, completely different experience. That is exactly why the regimen matters so much.
Which side effects come with tadalafil?
Headache is the most reported side effect with tadalafil too, followed by flushing, a blocked nose and stomach complaints. What sets tadalafil apart is back pain and muscle pain, usually in the lower back or thighs. Those are clearly less common with sildenafil.
That muscle pain often starts 12 to 24 hours after taking it and lasts a day or two. The cause is not fully explained.
The blue tint to vision known from sildenafil is rarer with tadalafil. That is because tadalafil affects the related enzyme in the retina less.
The nitrate warning applies in full. Combining it with nitroglycerin, isosorbide dinitrate or poppers can drop blood pressure dangerously, and with tadalafil that risk lasts longer because of the long duration.
Tadalafil and your prostate
Tadalafil 5 mg daily is also prescribed in the Netherlands for urinary complaints from a benign enlarged prostate. It relaxes the smooth muscle in the prostate and bladder neck. Men who have both urinary complaints and erection problems can sometimes address both sides.
That is not a small group. Both complaints increase with age and often occur together, as we described in enlarged prostate and erection problems.
Watch the combination with alpha blockers such as tamsulosin. Both lower blood pressure, so your doctor looks at that specifically.
What does your doctor check before you start?
Your GP mainly looks at your heart, your blood pressure and your other medication. That is not a formality but the core of the safety assessment, precisely because of nitrates and alpha blockers. Blood values are sometimes added when the complaints give reason to.
In men who do not respond to a PDE5 inhibitor, testosterone is one of the things that comes into view. Older research in men with diabetes showed that addressing a deficiency could improve the response.
Around 30 to 35 percent respond poorly to a PDE5 inhibitor, so that question is not rare. We wrote about the signals of low testosterone and about measuring testosterone.
A testosterone test brings some of those values into view. What the result means is something your GP will explain.
Tadalafil or sildenafil?
A direct comparison from 2017 found both medicines effective, with differences in profile rather than in strength. In practice the choice is about duration, side effect pattern and what your sex life looks like. Tadalafil suits spontaneity, sildenafil suits planning per occasion.
The full four-way comparison sits in ED medications compared. We cover the side effects of sildenafil in the article on Viagra.
What I would watch myself
If you start tadalafil, keep a short note for the first two weeks of when you took it and what you noticed. Back pain that only shows up the next day never gets linked to yesterday's pill otherwise.
Take that list to your GP. It makes the conversation about dose and regimen concrete instead of vague. If desire plays a role too, read low libido in men.
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
References
- Gong B, et al. Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction. Int Urol Nephrol, 2017. PMID: 28741090
- Tienforti D, et al. Comparative evaluation of on-demand PDE5 inhibitor efficacy in erectile dysfunction. J Sex Med, 2026. PMID: 42296271
- Shabsigh R, et al. Oral testosterone undecanoate reverses erectile dysfunction associated with diabetes mellitus in patients failing on sildenafil citrate therapy alone. Aging Male, 2003. PMID: 12898793
- Farmacotherapeutisch Kompas, monograph for tadalafil.
Autor
Caliberhealth
Dr. Naimi, lekarz wpisany do holenderskiego rejestru BIG, nadzoruje standardy medyczne naszych treści i ocen. Przeczytaj naszą politykę medyczną
