Which of the three cards if dinner is never skipped?
Three cards, one Copenhagen shelf
Line the three blister marks this site actually uses. A 10 mg Cialis card for as-needed use. A 25 mg Viagra diamond as the caution start. A Levitra pair: 2.5 mg when CYP3A4 is loud, 20 mg as the labeled high card. Other clinics will quote 50 mg sildenafil or 10 mg vardenafil as everyday opens. Fine. This folio matches our locks so the shelf stays internally honest.
Shared mechanism is boring on purpose: sexual stimulation, nitric oxide, cGMP, PDE5 blockade, more blood in cavernosal muscle. None of the three creates desire. None of the three is safe with a nitrate.
The useful differences are clocks, food, a QT avoid that sits on one card, and how long a nitrate stay-away lasts. Draw those. Note them on one table. Shelf-check the man's list. Bind without a crown.
Avanafil exists in other pharmacies and is not on this Copenhagen shelf. We will not smuggle a fourth card into the table to look complete. Three locks, three clocks, three nitrate sentences. That is the match. If a clinic starts sildenafil at 50 mg or vardenafil at 10 mg, that clinic is not wrong - it is using the everyday opens. This folio stays honest to 25 mg and 2.5-or-20 so the rest of the site does not argue with itself.
A match table, not a crown
| Mark on this shelf | Cialis 10 mg PRN | Viagra 25 mg | Levitra 2.5 or 20 |
|---|---|---|---|
| Role here | As-needed card (daily 2.5-5 is a separate folio) | Caution first diamond | CYP3A4 floor or labeled ceiling |
| Typical Tmax | ~2 hours | ~1 hour fasted | ~1 hour fasted |
| Half-life | ~17.5 hours | ~4 hours | ~4-5 hours |
| Label window often cited | Up to 36 hours | Same-evening (30 min-4 h plan) | Same-evening (from ~25 min) |
| High-fat food | No meaningful change | Tmax +~60 min, Cmax -~29% | Cmax down, Tmax may slip ~1 h |
| Nitrate note | Contraindicated; 48 h emergency gap | Contraindicated (origin of the miss) | Contraindicated; no interval given |
| Extra hold | Standing exposure if daily is chosen | Empty plate if the clock is tight | QT / IA / III avoid |
Read the rows as counseling marks, not as a contest. A 25 mg diamond is not 'weaker' than a 20 mg Levitra tablet. A 10 mg Cialis is not 'twice a 5.' Different molecules, different locks on this shelf.
Duration is a window, not a score
Sildenafil's half-life is about 4 hours. Practical cover for most men is a same-evening window, not a next-afternoon promise. That is a feature if you want the drug gone, and a nuisance if Saturday was supposed to bleed into Sunday.
Vardenafil's half-life is about 4 to 5 hours. Same short-board logic. Do not advertise it as a weekend tablet. Do not punish it for not being tadalafil.
Tadalafil's half-life near 17.5 hours is why the 10 mg card can still be working the next day, and why a nitrate, if ever discussed in an emergency, waits 48 hours. Longer is not 'better.' Longer is more standing exposure if you later need a spray, an alpha-blocker change, or a strong CYP3A4 drug.
Daily 2.5 mg or 5 mg tadalafil is not a fourth column on this table. It is a different route of the same molecule and has its own folio. Do not read a 36-hour PRN window and a daily strip as two extra 'wins' for Cialis in a comparison against short-clock cards. One molecule, two rhythms - argued next door, not here as a hidden crown.
Who even reaches for which card
A 10 mg Cialis card fits a thin calendar that still wants a forgiving window, or a dinner that will not be delayed. Flip to the daily strip only after the decision folio, not from this table.
A 25 mg Viagra diamond fits a first cautious start, a high AUC risk (age, liver, kidneys, CYP3A4), or a man who will actually clear the plate. It is a poor fit if every evening is a feast and nobody will wait.
Levitra 2.5 mg fits a strong-inhibitor list and a clean QT line. Levitra 20 mg fits a man who already tried a mid mark and still needs more effect, with no antiarrhythmic in the box. If the QT line is dirty, this card is not on the shelf.
Colour wash that bothers every evening is a reason to prefer the wider PDE6 gap on tadalafil, not a reason to keep climbing Levitra to 20 mg to 'see if it clears.' Headache that tracks the short clock is a reason to try a different evening plan, or a different card, after a fair trial - not a reason to stack two molecules in one weekend.
QT and nitrate as shared and unshared holds
All three cards are shut with nitrates and with riociguat. Sildenafil's origin file is literally that collision. Tadalafil writes a 48-hour emergency gap. Vardenafil writes that a safe nitrate interval has not been determined. None of those sentences is a home experiment.
Only vardenafil carries the extra QT avoid: congenital long QT, Class IA, Class III. If that line is dirty, do not 'pick Levitra because it is potent.' Pick a different card or pick no card. The selectivity slip exists so this match file does not have to retell the 59-man QT study.
CYP3A4 inhibitors rewrite all three rows, but they rewrite them differently. Tadalafil PRN stretches to 10 mg every 72 hours and daily caps at 2.5 mg. Sildenafil often falls to the 25 mg diamond, and ritonavir makes that diamond a 48-hour ceiling. Vardenafil can fall all the way to 2.5 mg in 72 hours. Same enzyme family, three different rewritten slips. That is another reason not to treat milligrams as exchange rates.
Alpha-blockers and antihypertensives can potentiate hypotension on all three. Stabilize the other drug first. Start at the low end of whichever card you bind. Sudden vision or hearing loss, and an erection past four hours, are class stops.
Onset clocks that do not match
Sildenafil on an empty stomach often peaks near an hour (30 to 120 minutes). The label lets you swallow from about 30 minutes to 4 hours before sex. A fatty plate can push that peak about an hour later.
Vardenafil's fasted Tmax is also near 60 minutes. The tablet may be taken from roughly 25 minutes to several hours before sex. A high-fat meal can delay that clock too. Bioavailability near 15 percent makes the onset feel punchy or thin depending on CYP3A4 company.
Tadalafil's Tmax sits nearer two hours, which sounds slower until you remember the 36-hour window on the 10 mg card. You are not trying to hit a 70-minute appointment the way you might with a short clock. You are laying a longer board.
Stimulation is required on every row. A swallowed tablet without arousal is a quiet blood level, not a failed brand. Men who judge a first attempt in a rushed, unstimulated, heavy-meal setting are scoring the setup, not the molecule. Give a card two or three honest evenings before you declare it dead and reach for the next blister.
Food, fat, and an empty plate
Viagra's leftover from the angina programme is the plate rule: high-fat meals delay Tmax about 60 minutes and cut Cmax about 29 percent. If the 25 mg diamond is meant to be punctual, clear the plate. Details sit in the origin file.
Levitra may be taken with food. A heavy plate can still slow it. A moderate plate usually does not. That is a softer food sentence than sildenafil's, not a food-blind sentence.
Cialis 10 mg does not care about dinner. That is the cleanest food line of the three. It is a reason to pick tadalafil if meals are never skipped. It is not a reason to ignore the 48-hour nitrate hold.
Alcohol is not a fourth column and still belongs in the same breath as food. Heavy drink plus any PDE5 is two vasodilator ideas. A 'relaxed dinner' that is mostly wine can look like a food-effect complaint when it is an alcohol complaint. Ask the plate and the glass separately before you blame the lock.
Pick a card after the holds
Draw three marks: 10 mg, 25 mg, 2.5-or-20. Note clocks, plates, and the nitrate sentences that do not match. Shelf-check QT only on the Levitra row, and CYP3A4 on all three. Bind one card.
No crown. A longer window is not a better man. A smaller first diamond is not a weaker drug. A 20 mg ceiling is not a trophy.
If the failure has not been named, stop matching cards and open the work-up folio. A comparison cannot replace a diagnosis.
Bring the bound card to a clinician who can see kidneys, the ECG if Levitra is in play, and the full bottle list. This shelf teaches a match. It does not dispense. A favourite molecule with a dirty hold is still the wrong bind, even if a forum voted it first.
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Reader mail
Reader questions on this review
Answered by Dr. Ingrid Halvorsen, MD · Internal medicine & clinical pharmacology
Match-file letters try to make me pick a champion. I will not. I will line up this site's three locks - 10 mg, 25 mg, 2.5 or 20 - against a clock, a plate, and a hold. Your own clinician still owns the prescription.
The 10 mg Cialis card is the food-blind one. Sildenafil's 25 mg diamond loses punctuality after a high-fat plate. Vardenafil usually survives a moderate meal and can slow after a heavy one. If the couple will not delay dinner and will not delay sex, tadalafil's lack of a food effect is the practical bind - after the nitrate line is clean. That is not a crown. It is a plate. If the man also wants standing cover, that is a different folio: daily 2.5 or 5 mg, not this match table.
Short clock versus long window - who actually picks 10 mg Cialis?
Someone who wants Saturday night to still be possible Sunday without a second swallow, and who accepts a longer standing presence if a nitrate ever becomes an emergency question. The 10 mg card is a window, not a sprint. Men who want the drug gone by morning often prefer the 25 mg diamond or a Levitra mark. Men who hate a 70-minute appointment often prefer tadalafil. Neither preference is a moral win. If the calendar is two evenings a month, the long window can still be the right PRN card - you are not obligated to move to a daily strip just because the half-life is long.
Is a 25 mg Viagra diamond even comparable to Levitra 2.5 mg?
Only as counseling marks on this shelf, not as equal currencies. 25 mg is our caution start when sildenafil exposure may run high. 2.5 mg is Levitra's interaction floor for strong CYP3A4 inhibition. A man on ritonavir might see both numbers in the same month for different reasons. A man with a clean list will usually not live at either lock: his clinic may open sildenafil at 50 mg and vardenafil at 10 mg. This match file refuses to say 25 is 'weaker' than 2.5 or the reverse. Compare the hold that put the number on the slip, then compare clocks.
Does the QT line knock Levitra off the shelf for everyone?
No. It knocks it off for congenital long QT and for Class IA or Class III antiarrhythmics. For a man with a quiet ECG and no such drug, Levitra remains a usable short-clock card, with 20 mg as a ceiling after a mid-dose trial and 2.5 mg when CYP3A4 is loud. What the QT line does is stop trophy talk. You do not pick vardenafil because a forum said it is 'most potent.' You pick it after the QT sentence is clean, the same way you pick any card after the nitrate sentence is clean.
Nitrate hold hours - 24, 48, or unknown - which card is least messy?
None of them is friendly with a nitrate. All three are contraindicated. Tadalafil at least writes a 48-hour emergency gap. Sildenafil's origin file is the GTN collision itself; clinics often speak in a 24-hour neighbourhood, but the home rule is still 'do not combine.' Vardenafil refuses to name an interval at all. The least messy card is the one you are not taking if a spray is still in the pocket. If the nitrate has been retired by a cardiologist, any of the three may be discussable. If it has not, this table has no winner row - it has a blank shelf.
Can I keep two cards and rotate by weekend?
Not as a home project. Rotating stacks half-lives you are not tracking, doubles the chance of a nitrate surprise, and makes a side-effect diary unreadable. If one card failed after a fair trial - right food, stimulation, enough attempts - a prescriber may switch the molecule. That is a rewrite of the slip, not a cocktail. Do not take Cialis 10 mg on Friday and a 25 mg diamond on Saturday because a forum called it 'stacking smart.' One PDE5 at a time.
Empty plate - is that rule only for the Viagra diamond?
It is loudest for the 25 mg diamond: high-fat meals delay Tmax about an hour and cut Cmax about 29 percent. Levitra can slow after a heavy plate and usually does not after a moderate one. Cialis 10 mg is food-blind. So 'empty plate' is not a house rule for the whole shelf. It is the leftover PK on the sildenafil row, and a maybe on the vardenafil row. If the evening is a feast, either pick the 10 mg Cialis card or accept a later short-clock peak. Do not add a second tablet because dinner made the first one late.
Why refuse a crown if one window is obviously longer?
Because longer is a trade, not a medal. A 36-hour Cialis window is standing exposure if a chest spray ever becomes necessary. A 4-hour sildenafil window is a tighter date and a cleaner next-morning blood level. Levitra's QT avoid is irrelevant to a man with a normal ECG and decisive for a man on amiodarone. Crowns flatten those trades into a personality contest. This folio is a match file. Bind the card that fits the hold, the plate, and the calendar.
If one card already failed, is the next one automatic?
No. First ask whether the failure was the molecule or the setup: no stimulation, a fatty plate on a short-clock drug, one lonely attempt, a dirty hold, or an unnamed cause. The AUA still wants a morning testosterone in men with ED. Nitrate users do not get a second card. After a fair, clean trial, switching molecules is reasonable because food effect and duration differ. Automatic hopping after one blank Friday is how people collect blisters and never name the failure. Start at the work-up folio if that naming never happened.
These replies are teaching, not a treatment plan for the person who asked. Take your own history, labs and medicine list to a prescriber who can see all three.