Levitra vs Viagra: Which One Suits You Better?

The main differences between Levitra and Viagra

Erectile dysfunction (ED) can be a sign of other health problems, such as heart disease and diabetes, so a new erection problem is worth raising with a doctor [1, 2]. Plenty of men find it awkward to bring up, which is understandable, but for a GP or pharmacist it's an everyday conversation.

Both Levitra and Viagra are oral medications used to treat erectile dysfunction, and they belong to the same class of medicines, phosphodiesterase type 5 (PDE5) inhibitors. Neither one causes an erection by itself. Each works only when you're sexually aroused [3, 4].

This guide is for men with ED weighing up Levitra or Viagra, whether they're starting treatment or their first tablet hasn't suited them. In a Levitra vs Viagra comparison, the two medicines are closely matched, so rather than naming a ‘winner ', it sets out where they differ (food, side effects and a few cautions that apply only to vardenafil) to help you discuss the choice with a prescriber.

Levitra is the original brand name for vardenafil, and generic vardenafil tablets contain the same active ingredient [4, 5]. Viagra is the brand name for sildenafil citrate, which is also sold as generic sildenafil and as Viagra Connect, a 50 mg version available from pharmacies. 

	Levitra (vardenafil)	Viagra (sildenafil)
Drug class	PDE5 inhibitor	PDE5 inhibitor
Needs sexual arousal to work	Yes	Yes
Usual starting dose	10 mg	50 mg
Dose range	5 mg to 20 mg	25 mg to 100 mg
When to take it	25 to 60 minutes before sex	About 1 hour before sex
Peak blood level (empty stomach)	30 to 120 minutes (median 60)	30 to 120 minutes (median 60)
Half-life	About 4 to 5 hours	3 to 5 hours
Effect of food	Slowed by a high-fat meal; a moderate-fat meal made no difference	Slowed by food; peak about 1 hour later
Maximum use	Once a day	Once a day
UK supply	Prescription only	Prescription; 50 mg Viagra Connect from pharmacies

The biggest practical difference is access. Levitra and standars Viagra are prescription-only medicines in the UK, while  Viagra Connect (Sildenafil) 50 mg can may be supplied by a pharmacist without a prescription after an assessment [1, 2, 3, 4].

Vardenafil vs Sildenafil: how they differ

Arousal releases nitric oxide in the penis, raising a messenger called cGMP that relaxes smooth muscle, increasing blood flow into the penis. The enzyme PDE5 breaks cGMP down; vardenafil and sildenafil block it, so the signal lasts long enough for a firm erection [3, 4].

Vardenafil also slightly prolongs the QT interval, a measure of the heart's electrical cycle, by about 8 milliseconds at 10 mg. The clinical impact is unknown, but it's why vardenafil is best avoided with certain heart rhythm problems and medicines [4].

The US Food and Drug Administration (FDA) approved Viagra in 1998 and Levitra in 2003 [5, 6]. 

How quickly they work and how long they last

   

Timing is often the real question here, because nobody wants sex to feel like it's being run to a schedule. Both are taken on demand, shortly before sex, and on an empty stomach they peak in the blood and clear at much the same rate, so the timing gap between them is small [3, 4].

When Levitra takes effect

Levitra may start working from about 15 minutes for some men. Vardenafil is taken about 25 to 60 minutes before sexual activity, and in a laboratory study at 20 mg, some men had an erection firm enough for penetration 15 minutes after the dose, with the group as a whole doing clearly better than placebo by 25 minutes [4].

In a trial of 383 men taking vardenafil 8 hours before sex (attempts counted 6 to 10 hours after the dose), the average success rate for intercourse was 69%, against 34% on placebo [7].

When Viagra takes effect

You take Viagra about an hour before sex. In a laboratory study of 50 mg on an empty stomach, men who responded had an erection firm enough for sex after a median of 25 minutes (range 12 to 37). Another study showed it still worked 4 to 5 hours after a dose [3].

In men with mild to moderate ED, sildenafil 100 mg taken 8 hours before sex led to successful sexual intercourse in an average of 76% of attempts, against 50% on placebo, and 79% against 52% at 12 hours [8].

The trials differ in design, so they don't show either drug lasting longer, only that both can work beyond the 4 hours often quoted.

Food, alcohol and grapefruit

If sex usually follows a meal out, this is the part worth reading closely. Food is where the two genuinely differ. 

With food, sildenafil's peak arrives about an hour later and is around 29% lower. A high-fat meal (57% fat) delays vardenafil's peak by about an hour and lowers it by 20%, but a meal with 30% fat made no measurable difference. So vardenafil may cope better with an ordinary meal, though a heavy, fatty one can slow either [3, 4].

Alcohol doesn't appear to interact directly with either drug: in studies, neither added to alcohol's effect on blood pressure [3, 4]. The problem is that heavy drinking makes erections harder to get, which can make the medicine seem not to work, so the advice is to avoid drinking large amounts before sex [1, 2].

Grapefruit juice weakly blocks CYP3A4 in the gut wall, an enzyme that helps break both drugs down, so it can raise their blood levels. The vardenafil product information says to avoid the combination. For sildenafil, it describes only modest increases, but the NHS advises against grapefruit because it makes side effects more likely [1, 3, 4].

Side effects: Levitra vs Viagra

Both widen blood vessels slightly, which causes a mild, short-lived dip in blood pressure. In trials, side effects of both ED drugs rarely caused problems: vardenafil's were generally mild to moderate and short-lived, and few men stopped sildenafil because of side effects [3, 4].

Common side effects

Headache is the most frequent side effect of both, affecting more than 1 in 10 men. Dizziness, flushing, a blocked nose and indigestion are common with both, affecting up to 1 in 10 [3, 4].

The clearest difference is vision. With sildenafil, changes in colour vision, blurred vision and other visual disturbances are listed as common, and so is nausea. With vardenafil, visual disturbances, colour distortion and nausea are all listed as uncommon, affecting up to 1 in 100 [3, 4]. A 2021 network meta-analysis of 179 trials pointed the same way, linking sildenafil 100 mg more with visual disorders and vardenafil more with nasal congestion [9].

On vardenafil 20 mg, men aged 65 and over reported headache (16.2% vs 11.8%) and dizziness (3.7% vs 0.7%) more often than younger men [4]. If either medicine makes you dizzy or affects your vision, don't drive until it passes [1].

When to get medical help

Serious side effects are rare, but some need prompt action [1, 3, 4]:

• A prolonged erection lasting more than 4 hours (priapism) needs immediate medical help, as without treatment it can damage the penis and cause permanent loss of potency.
• Sudden loss of, or change in, vision means stopping the medicine and seeing a doctor straight away.
• Deafness has been reported with both medicines, so get any sudden change in your hearing checked.
• Chest pain, a seizure or signs of a severe allergic reaction, such as a swollen throat or tongue, need a 999 call.
• Blistering skin around the mouth, eyes, nose or genitals with flu-like symptoms is a rare but serious reaction, so seek medical advice urgently.
  

The product information says observational data suggest a higher risk of NAION, a sudden loss of blood supply to the optic nerve, after PDE5 inhibitor use [4]. A 2018 review that pooled five studies found no clear overall link, though it did find possible links with sildenafil and tadalafil. Because the studies were observational, other health factors may explain some of the risk [10].

Usual doses of Levitra and Viagra

Sildenafil usually starts at 50 mg, taken about an hour before sex. Depending on how well it works and how well you tolerate it, a prescriber may raise this to 100 mg or lower it to 25 mg [3]. Viagra Connect, the pharmacy version, comes only in a 50 mg strength [2].

The usual Levitra dosage starts at 10 mg of vardenafil, taken 25 to 60 minutes before sex, and can be raised to 20 mg or lowered to 5 mg. The maximum for either is one dose a day [3, 4]. Milligrams aren't comparable across the drugs: 10 mg of vardenafil isn't a weaker dose.

Some men may start lower because of other health conditions or drug interactions: sildenafil 25 mg with severe kidney impairment or liver impairment such as cirrhosis, certain interacting medicines (CYP3A4 inhibitors) or alpha-blockers; vardenafil 5 mg with mild to moderate liver impairment, severe kidney problems or alpha-blockers, and no more than 5 mg alongside erythromycin or clarithromycin. 

Neither requires a routine dose adjustment based on age alone. For vardenafil, increasing the dose to 20 mg in men aged 65 or over should be considered carefully, depending on individualt tolerability [3, 4].

Which is better for you?

For most men, neither of these erectile dysfunction medications is clearly better.

In a 2006 head-to-head trial, 931 men with diabetes, high blood pressure or high cholesterol took vardenafil 20 mg and sildenafil 100 mg for four weeks each. Of these, 38.9% preferred vardenafil, 34.5% sildenafil and 26.6% had no preference. Vardenafil met the test for being no worse than sildenafil, and some efficacy scores favoured it, though only nominally. Both were well tolerated [11].

Pooled analyses lean the other way. The 2021 network meta-analysis ranked low-dose sildenafil among the most effective options and recommended low-dose sildenafil and tadalafil as first choices [9]. Those comparisons are indirect, so they can't settle it for any one man.

In practice, the choice comes down to meal timing (a moderate meal seems to affect vardenafil less), side effects (especially visual changes on sildenafil), your heart and other medications (vardenafil has extra heart-rhythm cautions) and access (sildenafil 50 mg is available from pharmacies) [2, 3, 4]. 

Men who'd rather not plan around a tablet often look at Cialis vs Viagra instead, because tadalafil (Cialis) has a half-life of about 17.5 hours, roughly four times that of either drug [12].

Who should not take Levitra or Viagra

   

The two ED medications share most of their contraindications [3, 4]. You shouldn't take either if you:

• use nitrates in any form, such as GTN spray or tablets for angina, or amyl nitrite (poppers), because the combination can cause a dangerous drop in blood pressure
• take riociguat
• have a heart condition that makes sex inadvisable, such as unstable angina or severe heart failure
• have had a heart attack or stroke recently, generally within the last 6 months
• have low blood pressure (below 90/50 mmHg)
• have severe liver problems
• have an inherited eye condition such as retinitis pigmentosa
• have lost vision in one eye because of NAION
  

Vardenafil isn't used with kidney failure needing dialysis or with the HIV medicines ritonavir or indinavir, nor with ketoconazole or itraconazole tablets in men over 75. It's best avoided with QT risk factors such as congenital long QT syndrome, low potassium, or quinidine, procainamide, amiodarone or sotalol [4]. Sildenafil with ritonavir isn't advised [3].

Nicorandil, an angina medicine with a nitrate component, can also interact seriously with both. Both need extra care with alpha-blockers (blood pressure medications also used for an enlarged prostate), a curved or scarred penis (such as Peyronie's disease), conditions that raise priapism risk (sickle cell anaemia, multiple myeloma, leukaemia), bleeding disorders or an active stomach ulcer. 

Neither is for women or under-18s [3, 4].

Can you switch between Levitra and Viagra?

If the first tablet didn't work, it's easy to assume nothing will. Yes, you can switch with a prescriber's guidance, but make sure the first medicine had a fair trial. In trials of sildenafil 50 mg, 40.8% of the men it worked for reported better erections after the first dose (14.6% on placebo), rising to 78.4% after up to 8 doses (46.7% on placebo) [2].

A 2018 review estimated that 30% to 35% of men don't respond to a PDE5 inhibitor, and that 30% to 50% of those can be helped by advice on correct use and a full trial at an appropriate dose [13]. A heavy meal, too little sexual stimulation or too low a dose are worth ruling out first [3, 4].

If sildenafil still hasn't worked, vardenafil helps some men. In a 12-week trial of 463 men who said sildenafil hadn't worked, the average rate of successful intercourse on vardenafil rose from 10.5% to 46.1%, and 61.8% reported better erections, against 14.7% on placebo [14]. Their earlier non-response was self-reported, though, and the trial didn't retest an optimised course of sildenafil. Reviews treat switching as one option among several, without enough evidence to rank them [13].

If neither works, see your GP. Erectile dysfunction can be linked with high blood pressure, diabetes or heart disease, and non-tablet treatments exist [2, 13].

Frequently asked questions

Can I take Levitra and Viagra together?

No. Combining them, or either with another ED treatment, hasn't been studied for safety and isn't recommended. Take one, no more than once a day [3, 4].

Is Levitra available over the counter in the UK?

No. Vardenafil is prescription-only, whether it's supplied as Levitra or a generic version, so you'll need an assessment of your medical history by a doctor or prescribing service before you can get it [4]. Only sildenafil is available without a prescription: Viagra Connect 50 mg is sold in pharmacies after a chat with the pharmacist, and you're advised to see your doctor within 6 months to check for underlying causes [1, 2].

Can I drink alcohol with Levitra or Viagra?

Yes, within reason. In studies, alcohol didn't add to either drug's effect on blood pressure, but heavy drinking makes erections harder to get [1, 3, 4].

What if Viagra does not work for me?

Give it a fair try, and check how to use Viagra correctly: take it on an empty stomach if you can, as food can delay it, allow about an hour, and make sure there's enough stimulation. Many men need several attempts, and a prescriber may raise the dose [2, 3]. If it still doesn't help, a healthcare provider can look for causes and discuss vardenafil or other options [13, 14].

Can I take Levitra every day?

Like Viagra, Levitra (vardenafil) is licensed for use when needed, up to once a day, not as a regular daily treatment [3, 4]. If you'd rather not time a tablet around sex, low-dose tadalafil (2.5 mg or 5 mg) is licensed for daily use in men who expect sex at least twice a week [12].