ED Medication Comparison Chart

Four drugs, one mechanism. All four are PDE5 inhibitors, all four need sexual stimulation to do anything, and none of them is more "powerful" than the others in any sense a prescription pad cares about. What separates them is how fast they arrive, how long they stay, whether dinner matters, and how long they keep you locked out of a nitrate. Read across your row; the interactions table at the bottom is the one that can kill you.

Two things on this sheet are deliberately not the numbers you will find elsewhere. First, no FDA label for any of these four states an onset of action. Three state a lead time in the dosage section — "approximately 1 hour", "approximately 60 minutes", "as early as approximately 15 minutes" — and the CIALIS label states none at all, only "prior to anticipated sexual activity". Where a cell prints a figure, the small type under it says whether that figure is the label's own instruction or a median time-to-peak. The widely quoted "Cialis starts working in 30 minutes" appears nowhere on the CIALIS label and is not printed here.

Second, only two of the four labels state a duration of effect. Sildenafil's documents an effect for up to 4 hr and tadalafil's documents improved erectile function against placebo up to 36 hr. The vardenafil and avanafil labels make no duration claim whatsoever, so those two rows say "not stated" and give the terminal half-life instead, marked as such. A half-life is not a duration of effect and this sheet will not pretend otherwise.

Everything here describes the label. It does not describe what a clinic will prescribe you, what a pharmacy will dispense, or what a generic tablet will cost. These are prescription-only medicines and the choice between them belongs to the clinician writing the prescription.

Timing — and what each figure actually is

The small type under each figure is the point of this table. A dosage-section instruction and a median time-to-peak are different kinds of fact, and most comparison charts print them in the same column without saying so.

Avanafil's 15-minute lead time applies to the 100 mg and 200 mg tablets only — its label puts the 50 mg dose at approximately 30 minutes before activity. Sildenafil is the only one of the four whose label states an outer limit as well as a target: "VIAGRA may be taken anywhere from 30 minutes to 4 hours before sexual activity." The note on the vardenafil row: Quoted from the current-format generic vardenafil label. DailyMed lists no innovator LEVITRA label; its LEVITRA entries are repackager copies of the withdrawn pre-2011-format Bayer label.

Approved dosing, as needed

Starting dose, the range the dosage section supports by titration, and the tablet strengths actually manufactured. These are not always the same list.

The vardenafil 2.5 mg tablet is stocked for dose reduction with CYP3A4 inhibitors, not as a starting dose for erectile dysfunction — its dosage section never offers it as one. Sildenafil's label separately drops the starting dose to 25 mg for men over 65, men with hepatic impairment and men with severe renal impairment.

Once-daily dosing — the thing only tadalafil has

Three of these four exist only as a tablet you take before sex. Tadalafil has a second, separate, licensed regimen at a lower dose, and a prostate indication attached to it. Read down the tadalafil column.

Daily tadalafil starts at 2.5 mg — lower than the lowest as-needed dose of 5 mg — and is taken "at approximately the same time every day, without regard to timing of sexual activity". That is the trade: a tablet every day in exchange for never planning again. The same 5 mg daily dose is separately licensed for benign prostatic hyperplasia, which is why a man with both problems is often given tadalafil rather than one of the other three.

Food

Whether dinner changes anything, and by how much. Every one of the four is licensed to be taken with or without food; that is not the same as food making no difference.

Tadalafil is the only one of the four whose label states no food effect at all: "the rate and extent of absorption of tadalafil are not influenced by food". Sildenafil is the most affected — a high-fat meal pushes its peak back 1 hr and cuts it by 29%. The vardenafil label reports the drop in peak concentration but states no delay to the peak, so that cell is left empty rather than filled from a secondary source.

The interactions that matter

Nitrates are an absolute contraindication on all four labels — not a caution, not a "discuss with your doctor". The second column is the one almost no comparison chart carries: how long each label says must elapse after a dose before a nitrate can even be considered in an emergency.

Two of the four labels name an interval that must elapse before a nitrate can even be considered in a life-threatening situation: 12 hours for avanafil, 48 hours for tadalafil. The sildenafil label says it is unknown, and the vardenafil label says it has not been determined. None of the four says a nitrate is ever safe alongside a dose. The alpha-blocker column is a starting dose for a man already stable on alpha-blocker therapy, and three of the four labels name a figure; the CIALIS label says only "the lowest recommended dose" and does not number it, so that cell says so rather than guessing at 5 mg. For benign prostatic hyperplasia the CIALIS label goes further and does not recommend the combination at all.

Where the labels stop

What each FDA label does not say. This table is the reason several figures elsewhere on this sheet read "not stated" — those gaps are in the source documents, and filling them from a secondary source would make the chart look more complete and be less true.

Not one of the four labels states an onset of action. Three give a lead time in the dosage section, which is a dosing instruction rather than a pharmacodynamic measurement, and the fourth gives nothing. Any chart that prints a tidy "onset: 30 minutes" for all four has taken those numbers from somewhere other than the prescribing information.

Frequently asked questions

Which ED medication is the strongest?

That is not a question the labels answer, and the milligram numbers are not comparable across the four — 200 mg of avanafil is not "stronger" than 20 mg of tadalafil, they are simply different molecules with different potencies at the same enzyme. What the labels do let you compare is timing: avanafil is licensed to be taken "as early as approximately 15 minutes before sexual activity", sildenafil and vardenafil at approximately 1 hour and 60 minutes respectively, and tadalafil has no stated lead time at all but a median time to peak of 2 hr. On duration the gap is real and large: the CIALIS label documents improved erectile function against placebo up to 36 hr after a dose, where the VIAGRA label documents an effect up to 4 hr and weaker at 4 hours than at 2.

Can you take Viagra or Cialis with nitrates?

No, and this is the single most important line on this page. All four labels carry it as an absolute contraindication in section 4. VIAGRA: "VIAGRA was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated." CIALIS: "Administration of CIALIS to patients who are using any form of organic nitrate, either regularly and/or intermittently, is contraindicated." Vardenafil: "Administration of vardenafil with nitrates (either regularly and/or intermittently) and nitric oxide donors is contraindicated". STENDRA: "Administration of STENDRA with any form of organic nitrates, either regularly and/or intermittently, is contraindicated." That covers nitroglycerin in tablets, sprays, ointments, pastes and patches, isosorbide mononitrate and dinitrate, and the recreational nitrites sold as "poppers".

How long after taking an ED tablet can you take a nitrate?

The four labels give four different answers, and two of them are "we do not know". The CIALIS label states that "at least 48 hours should elapse after the last dose of CIALIS before nitrate administration is considered". The STENDRA label states "at least 12 hours". The VIAGRA label states: "After patients have taken VIAGRA, it is unknown when nitrates, if necessary, can be safely administered." The vardenafil label states that "a suitable time interval following dosing of vardenafil for the safe administration of nitrates or nitric oxide donors has not been determined." In every case the label adds that the nitrate should still only be given under close medical supervision with hemodynamic monitoring. If you take a PDE5 inhibitor and then get chest pain, the paramedics need to know what you took and when.

What is the difference between daily Cialis and Cialis as needed?

They are two separately licensed regimens on the same label. As needed, the starting dose is 10 mg "taken prior to anticipated sexual activity", adjustable between 5–20 mg, no more than once a day. Once daily, the starting dose is 2.5 mg "taken at approximately the same time every day, without regard to timing of sexual activity", increased to 5 mg on response — a lower dose than any as-needed dose. The 5 mg daily dose is also separately licensed for benign prostatic hyperplasia. None of the other three drugs on this chart has a once-daily regimen of any kind on its label.

Do I need to take these on an empty stomach?

All four labels permit them with or without food, but that is not the same as food making no difference. Sildenafil is the most affected: "When VIAGRA is taken with a high fat meal, the rate of absorption is reduced, with a mean delay in Tmax of 60 minutes and a mean reduction in Cmax of 29%." Avanafil's peak is delayed 1.12 to 1.25 hours and cut 39%, changes its label calls "of minimal clinical significance". Vardenafil's label reports a reduction in peak concentration of 18% to 50% with high-fat meals and states no delay to the peak. Tadalafil is the exception: "the rate and extent of absorption of tadalafil are not influenced by food".

How long does each one actually last?

Only two of the four labels answer that. Sildenafil: "The time course of effect was examined in one study, showing an effect for up to 4 hours but the response was diminished compared to 2 hours." Tadalafil: "CIALIS for use as needed was shown to improve erectile function compared to placebo up to 36 hours following dosing" — which is an efficacy window measured in a trial, not a 36-hour erection. The vardenafil and avanafil labels make no duration-of-effect claim at all, so this chart prints their terminal half-lives instead and marks them as such: approximately 4 to 5 hours for vardenafil and approximately 5 hours for avanafil. A half-life tells you how fast the drug leaves; it does not tell you how long it works.

I take an alpha-blocker for my prostate. Which ED medication can I have?

All four can be co-prescribed with care, and three of the four labels name the starting dose to use once you are stable on the alpha-blocker: 25 mg for sildenafil, 5 mg for vardenafil, 50 mg for avanafil. The CIALIS label says only that it "should be initiated at the lowest recommended dose" and does not put a number on it, so this chart does not put one there either. The rule common to all four is sequencing: be stable on the alpha-blocker first, then start the PDE5 inhibitor at the bottom of its range. For benign prostatic hyperplasia specifically, the CIALIS label states that it "is not recommended for use in combination with alpha-blockers for the treatment of BPH".

Why does this chart say "not stated" instead of giving me a number?

Because the FDA label it is quoting does not give one. Three figures are commonly published for these drugs that no label supports: an onset of action for any of the four, a duration of effect for vardenafil or avanafil, and a safe nitrate interval for sildenafil or vardenafil. Where a label is silent, this chart says so and shows the nearest thing it does state — a dosage-section lead time, a median Tmax, a terminal half-life — labelled as what it is. A chart with every cell filled is easy to produce and impossible to check.

Is Levitra still available, and is this chart using its label?

The vardenafil figures here come from the current-format generic vardenafil label from Zydus Pharmaceuticals, not from a LEVITRA-branded one. DailyMed no longer lists an innovator LEVITRA label; the LEVITRA entries it returns are repackager copies of the older pre-2011-format Bayer document, which has none of the numbered sections the modern labels use. Vardenafil itself is still marketed as a generic, at the same 2.5, 5, 10 and 20 mg strengths and the same 10 mg starting dose taken approximately 60 minutes before sexual activity.

Sources

1. [1]STENDRA (avanafil) tablet — Metuchen Pharmaceuticals, LLC. FDA prescribing information via DailyMed (setid fa7d93e3-b69b-4e02-8146-89760cd8e9d6)
2. [2]VIAGRA (sildenafil citrate) tablet, film coated — Pfizer Laboratories Div Pfizer Inc. FDA prescribing information via DailyMed (setid 0b0be196-0c62-461c-94f4-9a35339b4501)
3. [3]VARDENAFIL tablet, film coated — Zydus Pharmaceuticals USA Inc.. FDA prescribing information via DailyMed (setid 5876e062-e604-42a7-99c3-5da30b8dac06)
4. [4]CIALIS (tadalafil) tablet, film coated — Eli Lilly and Company. FDA prescribing information via DailyMed (setid bcd8f8ab-81a2-4891-83db-24a0b0e25895)
5. [5]LEVITRA (vardenafil hydrochloride), Aphena Pharma Solutions — Tennessee, Inc. — FDA patient labeling via DailyMed (setid 34c30372-08b0-4060-8aba-779b5bc1e5dd), quoted only for the patient-leaflet wording on "poppers"