Vardenafil vs Tadalafil: Key Differences

What is the difference between Vardenafil and Tadalafil?

Erectile dysfunction (ED) is very common, particularly in men over 40, and the main ED treatment is a group of medicines called PDE5 inhibitors [1]. Vardenafil and tadalafil both belong to this group. They work in the same way, and neither has been shown to work better than the other [2, 3, 4].

What sets them apart is practical, and the vardenafil vs tadalafil choice usually comes down to how soon each takes effect, how long it lasts, whether food slows it down, whether it can be taken daily, and which side effects are more likely. 

Each of these is covered below so you can go into a consultation knowing which tablet fits the way you want to use it.

How do they work, and how are they dosed?

During arousal, nitric oxide raises levels of a messenger molecule called cGMP in the penis, which relaxes the smooth muscles there, increasing blood flow. Blocking PDE5, the enzyme that breaks cGMP down, helps sustain that response, promoting blood flow to the penis during arousal. Neither tablet causes an erection on its own, and sexual stimulation is still needed [2, 3].

The biggest practical difference is how long each drug stays in the body. Vardenafil has a half-life of about 4 to 5 hours, while tadalafil’s is about 17.5 hours [2, 3]. That difference shapes most of what follows.

Vardenafil is usually started at 10 mg, and the dose can be lowered to 5 mg or raised to 20 mg depending on how well it works and how well it’s tolerated. On-demand tadalafil is also usually started at 10 mg, with 20 mg tried if needed, while lower 2.5 mg and 5 mg strengths are used for daily treatment. If you decide to buy Tadalafil online, the right strength is decided during a consultation and depends on whether you want to take it when needed or as a small daily dose [2, 3, 6, 7].

How quickly do they start to work?

Vardenafil is usually taken approximately 25 to 60 minutes before sexual activity, according to its product information, and tadalafil at least 30 minutes before [2, 3].

Some men respond sooner. In a study of 732 men timing their response at home, vardenafil worked better than placebo from as early as 10 minutes after a dose. Within 25 minutes, around half the men on vardenafil (50% on 10 mg, 53% on 20 mg) had at least one erection that led to successful sexual intercourse, compared with 26% on placebo [8].

A similar study of tadalafil found that the 20 mg dose outperformed placebo from 16 minutes, and 52% of men taking it had at least one successful attempt within 30 minutes, against 35% on placebo. Results for the 10 mg dose were weaker and less consistent [9].

These figures describe the fastest responders, and both studies are more than 20 years old, so the recommended timings are the better guide for most men.

How long do effects last?

Neither tablet produces a lasting erection. Each opens a window in which sexual stimulation can lead to one [2, 3].

Tadalafil’s window is longer. The tadalafil product information states that it can improve erectile function for up to 36 hours after a dose. In one trial, 59.2% of attempts at sex 36 hours after tadalafil 20 mg were successful, compared with 28.3% on placebo, and the results at around 24 hours were similar (52.9% vs 29.1%) [3, 10].

Vardenafil’s window is shorter, in line with its half-life. In its main trials, the small number of men who tried to have sex four to five hours after a dose still did better than on placebo. A later trial went further. Men who took vardenafil 8 hours before sex had successful intercourse in 69% of attempts, compared with 34% on placebo, although that trial didn’t test longer gaps [2, 11].

Whatever the window, don’t take more than one dose of either tablet in a day [2, 3].

Is a daily dose only possible with Tadalafil?

   

Yes. Tadalafil is the only one of the two licensed for daily use in the UK. For men who expect to use it at least twice a week, a doctor may suggest 5 mg once a day, taken at about the same time each day, with the option of dropping to 2.5 mg if side effects are a problem. The need for daily treatment should be reviewed from time to time [3].

Blood levels settle after about five days of daily dosing. In the main trials, men taking tadalafil 5 mg daily had successful sex in 57% and 67% of attempts (two separate studies), compared with 31% and 37% on placebo. In men who hadn’t used a PDE5 inhibitor before, the success rate was 68% on tadalafil against 52% on placebo. The same 5 mg daily dose is also licensed for the urinary symptoms of an enlarged prostate [3].

Vardenafil is licensed only for use when needed, up to once a day [2].

Does food change how they work?

It can with vardenafil. In studies, taking a vardenafil tablet with a high-fat meal (57% fat) delayed the time to peak blood level by about an hour and lowered the peak by around 20%, which may delay the effect. A meal with 30% fat made no difference. Taking tadalafil with food doesn’t change how it’s absorbed, so it can be taken with or without a meal [2, 3].

Grapefruit juice can raise vardenafil levels, so the two shouldn’t be combined. It’s expected to raise tadalafil levels too, and the NHS advises not drinking grapefruit juice while taking tadalafil [2, 3, 12].

Alcohol didn’t change how vardenafil was absorbed in studies. With tadalafil, larger amounts of alcohol caused dizziness on standing in some men, and the NHS notes that alcohol can raise the risk of low blood pressure and make erections harder to get [2, 3, 12].

Vardenafil vs Tadalafil: Side effects compared

Side effects of both tadalafil and vardenafil are usually mild to moderate and short-lived. Each drug’s side-effect list comes from its own trial programme, so the lists can’t be compared directly [2, 3].

One recent analysis of placebo-controlled trials found the odds of treatment-related side effects were highest with vardenafil and lowest with tadalafil. Its authors cautioned that the estimates overlapped and the differences may not be statistically significant [4].

Back pain and muscle ache

This is the clearest difference between the two. Back pain, muscle ache and pain in the arms or legs are listed as common with tadalafil, while back pain and muscle ache are listed as uncommon with vardenafil [2, 3].

In pooled data from 10 tadalafil trials, back pain or muscle ache affected 9.4% of men on 10 mg and 8.3% on 20 mg, against 3.7% on placebo, and fewer than 1% stopped treatment because of it. Tests in healthy volunteers found no signs of muscle damage or inflammation. The cause remains unknown, but the pain tends to settle on its own [13].

Vision changes

Changes in vision are linked to PDE6, the retinal enzyme that vardenafil affects more than tadalafil does. With vardenafil, visual disturbance, altered colour vision, eye pain and sensitivity to light are listed as uncommon. With tadalafil, blurred vision is uncommon, and changes in colour vision were rare across its trials, affecting fewer than 0.1% of men [2, 3, 5].

A rare but serious problem applies to both. Non-arteritic anterior ischaemic optic neuropathy (NAION), in which reduced blood flow damages the optic nerve, has been reported with both drugs, and observational studies suggest a raised risk in men with erectile dysfunction after taking a PDE5 inhibitor. Anyone who notices sudden loss of vision should stop the tablet and get medical help straight away. Men who have previously lost vision in one eye because of NAION shouldn’t take either drug [2, 3].

Headache, flushing and nasal congestion

Headache is the most common side effect of vardenafil, affecting more than 1 in 10 men, while flushing, a blocked nose, indigestion and dizziness are common. With tadalafil, headache, flushing, a blocked nose and indigestion are all common, and most headaches on daily tadalafil happen within the first 10 to 30 days of treatment. An analysis of trials across all PDE5 inhibitors found vardenafil among those most likely to cause nasal congestion [2, 3, 14].

Who should not take Vardenafil or Tadalafil?

   

Both drugs can be unsafe alongside certain medicines and existing health conditions [2, 3]. Neither is suitable if you:

• take nitrates for chest pain, such as glyceryl trinitrate (GTN)
• take riociguat, as combining it with either drug can make your blood pressure drop too low
• have heart disease severe enough that sexual activity isn’t advisable, including unstable angina, or have low blood pressure (below 90/50 mmHg)
• have lost vision in one eye because of NAION

Beyond that, the lists differ. Vardenafil also can’t be combined with other nitric oxide donors, such as amyl nitrite (“poppers”). It isn’t used within 6 months of a heart attack or stroke, or in men with severe liver disease, kidney failure needing dialysis, or inherited retinal conditions such as retinitis pigmentosa. It can’t be taken with the HIV medicines ritonavir or indinavir, and it needs caution in men with certain heart-rhythm risks because it can slightly lengthen the QT interval [2].

Tadalafil isn’t used within 90 days of a heart attack or 6 months of a stroke, or in men with angina during sex, heart failure that has limited everyday activity in the last 6 months, uncontrolled heart rhythm problems or uncontrolled high blood pressure. Tadalafil is also contraindicated with nitric oxide donors such as amyl nitrite (“poppers”), because the combination can cause a potentially dangerous drop in blood pressure [3, 12].

Both need care alongside alpha-blockers, a group of blood pressure medications that are also used for prostate symptoms, and tadalafil isn’t recommended with doxazosin. Because tadalafil lasts so long, at least 48 hours should pass after the last dose before nitrates are given in an emergency. Several other prescription medications, including some antibiotics and antifungals, can raise levels of either drug [2, 3].

Tell your healthcare provider about any other medications you take, including anything bought without a prescription, and read the patient information leaflet in the pack before your first dose.

Which one suits you better?

There’s little direct evidence comparing the two. The most recent network analysis found no trial in its data set that tested vardenafil against tadalafil, and in its indirect comparison of placebo-controlled trials, vardenafil 10 mg and tadalafil 20 mg performed about equally well [4]. That leaves most of the decision to practicalities, summarised below [2, 3, 11, 12, 15].

	Vardenafil	Tadalafil
When to take (on demand)	About 25–60 minutes before sex	At least 30 minutes before sex
Half-life	About 4–5 hours	About 17.5 hours
Window of effect	Several hours; trial evidence up to 8 hours	Up to 36 hours
Daily dosing	Not licensed	2.5 mg or 5 mg once a day
High-fat meal	Can delay the effect	No effect on absorption
Back pain and muscle ache	Uncommon	Common
UK supply	Prescription only	Mostly prescription; one 10 mg product from pharmacies

Tadalafil may suit men who want a longer window, would rather not plan sex around a tablet, or prefer a small dose every day, and food won’t affect it. Vardenafil may suit men who prefer a shorter-acting tablet, or who’ve had troublesome back or muscle pain on tadalafil, as that side effect is less common with vardenafil [2, 3].

In preference studies where men tried more than one tablet, 52% to 65% chose tadalafil, compared with 12% to 20% for vardenafil, mainly because of its longer duration. Those studies date from 2000 to 2010, however, and the reviewers noted serious limitations, including differences in the doses being compared [16].

Apart from one pharmacy pack of tadalafil, both need a prescription, so the choice is usually made with a prescriber [2, 12].

Frequently asked questions

Is Vardenafil or Tadalafil better for ED?

Neither has been clearly shown to be superior for treating ED. There is limited head-to-head evidence, and indirect comparisons suggest that vardenafil and tadalafil have broadly similar efficacy, although the evidence does not establish that they are equivalent [4].

Is Levitra the same as Cialis?

No. Levitra is a brand of vardenafil and Cialis is a brand of tadalafil, so they contain different active ingredients, although both are PDE5 inhibitors. The Levitra brand has been discontinued in the UK, and vardenafil is now supplied as a generic version. Men who prefer the branded tablet can get Cialis online in UK after a consultation and have the same longer window of effect [2, 3, 6, 10].

Can you switch between Levitra and Cialis?

Yes, on a prescriber’s advice, but not by taking both. Combining a PDE5 inhibitor with other ED medications hasn’t been studied and isn’t recommended [2, 3]. UK prescribing guidance suggests trying at least four, and preferably eight, doses at the highest tolerated dose before deciding a tablet hasn’t worked, then considering a different PDE5 inhibitor, as limited evidence suggests some men respond better to one than another [17]. 

In a trial of men who hadn’t responded to sildenafil, 30% of those given vardenafil reached normal erectile function, against 6% on placebo, although that trial looked at switching from sildenafil rather than between vardenafil and tadalafil [18].

Can you buy them without a prescription in the UK?

Vardenafil is prescription-only. Tadalafil mostly needs a prescription too, but one product, Cialis Together 10 mg, can be bought from a pharmacy by men over 18 after a conversation with a pharmacist. It’s limited to one tablet a day and packs of up to eight [2, 15].

If you buy tadalafil without a prescription, a pharmacist should check that it is suitable for you. Erection problems can be a sign of conditions such as diabetes or heart problems, so understanding erectile dysfunction’s cause matters as much as treating it [12].

How do they compare with Sildenafil?

Sildenafil is another PDE5 inhibitor, and it can be bought from a pharmacy as well as on prescription [1]. Like vardenafil, it’s short-acting, and a high-fat meal can slow its absorption, while tadalafil lasts the longest of the three [4]. Weighing up Sildenafil vs Tadalafil comes down to much the same trade-offs as this comparison: a shorter window that a heavy meal can delay, against a longer one that food doesn’t affect.