What do IIEF, SEP2, and SEP3 actually ask me?
Which IIEF points a 20 mg Cialis trial actually posts
A slogan cannot be randomized. A questionnaire can. Start with the six questions that make the erectile-function domain, or you are reading an ad.
Rosen's IIEF is a 15-item form. The erectile-function domain, IIEF-EF, sums six of those items on a 1-to-5 scale and runs from 6 to 30. Twenty-six or higher is the usual 'normal' cut. Mild sits 22-25, mild-to-moderate 17-21, moderate 11-16, severe 10 or below. A trial that only says 'erections improved' has not posted a signal. A trial that moves IIEF-EF several points past placebo has.
Beside the form sit two diary questions. SEP2 asks whether penetration was possible. SEP3 asks whether the erection lasted long enough to finish. SEP3 is the harder bar and the one I watch. GAQ is a blunt yes-or-no: did treatment improve your erections? When IIEF-EF, SEP2, SEP3, and GAQ all move the same way, you are not looking at one flattering item. The pharmacology behind those moves is in the tadalafil reference.
Brock 2002: five trials, 1112 men, 20 mg points
Brock and colleagues pooled five randomized, double-blind, placebo-controlled phase 3 studies from 74 centers. Mean age was 59. Etiology was about 61 percent organic, 9 percent psychogenic, 31 percent mixed. Severity at baseline was mild in 41 percent, moderate in 23 percent, severe in 36 percent. Men took tadalafil from 2.5 mg up to 20 mg before activity, at most once a day, for 12 weeks.
IIEF-EF rose 6.5 points on 10 mg and 7.9 points on 20 mg, against 0.6 on placebo. SEP3 successful-attempt rates improved 34 percentage points on 10 mg and 39 on 20 mg, against 6 on placebo. More than 70 percent of attempts from 30 minutes to 36 hours after a dose succeeded on drug. GAQ improved-erection rates were 81 percent on 20 mg versus 35 percent on placebo. Fifty-nine percent of men on 20 mg reached an IIEF-EF of 26 or higher, against 11 percent on placebo. Those are the points. Not a slogan.
Porst timed the window. The slogan came later.
Duration was measured as successful attempts at stated hours, not as a weekend brand.
Porst presented timed data at the 2002 AUA meeting and published the 36-hour window in 2003. The design asked whether a man could still complete intercourse many hours after a swallow. He could, at rates that stayed close across that span. Carson and colleagues later stacked eleven trials, including Brock's original 1112 men plus 1215 more, and saw IIEF-EF gains of 6.5 on 10 mg and 8.6 on 20 mg versus 0.9 on placebo. SEP3 totals reached 58 percent on 10 mg and 68 percent on 20 mg versus 31 percent on placebo. GAQ yes-rates were 71 and 84 percent versus 33 percent.
A tertiary-care cohort with more severe, organic ED still moved. Carson 2005 reported a 6.9-point IIEF-EF gain on 20 mg against a 0.2-point loss on placebo, SEP3 improvement of 34 versus 4.5 percentage points, and a GAQ of 73 versus 15 percent. Hard-to-treat groups - diabetes, post-prostatectomy, post-radiotherapy - have their own stacks. They are smaller and the absolute rates are lower. The direction stays the same. The 20 mg PRN card is the SERP strength this post keeps in view when the question is 'does the weekend tablet actually score.'
Daily 5 mg: three phase 3 pings, no event clock
| File | Primary scorecard | What the signal posted |
|---|---|---|
| ED, 10-20 mg PRN (Brock / Carson) | IIEF-EF, SEP2, SEP3, GAQ | IIEF-EF +6.5 to +8.6 vs placebo ~+0.6 to +0.9 |
| ED, 20 mg timed (Porst) | Successful attempts by hour | Window held out to 36 hours |
| ED, 2.5-5 mg daily (2008 trio) | IIEF-EF, SEP2, SEP3 | Gains without dosing to an event |
| BPH, 5 mg daily (2011) | IPSS | Symptom score down vs placebo |
| ED + BPH, 5 mg daily | IIEF-EF and IPSS | Both moved on one 5 mg strip |
| PAH, 40 mg (PHIRST-1) | 6-minute walk | +33 m vs placebo at 16 weeks |
The January 2008 daily clearance rested on three phase 3 randomized, double-blind, placebo-controlled studies of 2.5 mg and 5 mg taken every day without tying the swallow to sex. IIEF-EF, SEP2, and SEP3 moved against placebo on both daily strengths. The 5 mg daily strip is the usual working dose when the first 2.5 mg is tolerated. Daily is not a potency upgrade on 20 mg PRN. It is a steady-level design for a busy calendar.
Rajfer, Porst, Hatzichristou, and McMahon published the daily series that made that lane possible. The practical split - who should live on 5 mg daily versus who should keep a 20 mg PRN card - is a calendar question, worked in the calendar-split post. The evidence question is simpler: both lanes posted IIEF points. Neither lane is a rumor.
IPSS for the prostate. IIEF will not do that job.
Benign prostatic hyperplasia is scored on the International Prostate Symptom Score: weak stream, frequency, urgency, nocturia. Higher is worse. A treatment earns the indication by driving IPSS down. The 2011 program used three placebo-controlled 12-week studies in 1,989 men - two BPH-only, one ED-plus-BPH. Daily tadalafil 5 mg lowered IPSS against placebo. In one published ED-plus-BPH study the 5 mg arm also lifted IIEF-EF by about 4.7 points and cut IPSS by about 2.3 points versus placebo.
Flag the limit. Tadalafil eases how the symptoms feel. It does not reliably raise peak flow the way an alpha-blocker can, and it does not shrink the gland the way a 5-alpha-reductase inhibitor can. It is a symptom treatment that can also cover ED on the same 5 mg daily strip. That convenience is real. It is not a structural prostate drug. Combining tadalafil with an alpha-blocker as a dual BPH plan is the hypotensive stack the label does not want. Tadalafil 5 mg daily as monotherapy for BPH is the approved lane.
PHIRST walked 33 meters. That is a different desk.
Pulmonary arterial hypertension is not erectile dysfunction with a bigger tablet. The endpoint is how far a person can walk in six minutes.
PHIRST-1 (NCT00125918) randomized 406 adults to placebo or tadalafil 2.5, 10, 20, or 40 mg once daily for 16 weeks. The 40 mg arm - later Adcirca, two 20 mg tablets - gained 33 meters on the six-minute walk against placebo. Clinical worsening (death, transplant, septostomy, PAH hospitalization, new PAH therapy, or worse WHO class) was less common on 40 mg. Headache, myalgia, flushing, and nasal congestion were the usual transient events.
United Therapeutics took the US PAH license in November 2008. FDA clearance for Adcirca landed 26 May 2009. For a man who only wants a 20 mg weekend card or a 5 mg daily strip, PHIRST is a reminder that the same enzyme block can do life-altering work at a different dose in a different vascular bed. It is not a reason to raise your ED tablet toward 40 mg. The Bothell-to-label arc is in the Bothell priced-card post.
What a 5 mg daily Cialis receipt leaves off
A pharmacy receipt will show 5 mg daily or 20 mg PRN and a quantity. It will not show IIEF-EF points, SEP3 rates, or an IPSS change. Those live in the trial file, not on the bag. Coupon copy that says 'works 36 hours' is a leftover, not a scorecard. If you are comparing cash prices after the 2018 generic lapse, compare the same strength and the same count at a named US pharmacy. Do not paste a coupon URL onto a chain's name.
This desk does not fill. A licensed counter does. Bring the nitrate list, the alpha-blocker list, and any CYP3A4 inhibitor before anyone prices a strip. Patient-facing class language is on MedlinePlus. The current labeled endpoints sit on DailyMed.
Sibling drugs: same enzyme, different clocks
| Clock | Sildenafil | Tadalafil | Vardenafil |
|---|---|---|---|
| Half-life | ~4 hours | ~17.5 hours | ~4-5 hours |
| Window | ~4-6 hours | Up to ~36 hours | ~4-6 hours |
| Food | Fatty meal blunts | No meaningful effect | Fatty meal blunts |
| Labeled daily ED lane | No | Yes (2.5-5 mg; SERP 5 mg) | No |
| SERP PRN on this site | 100 mg class talk | 20 mg card | 10-20 mg class talk |
| Off-target PDE | PDE6 (visual tinge) | PDE11 (unclear) | PDE6 (visual tinge) |
| Nitrates | Hard stop | Hard stop; 48-hour wait | Hard stop |
Sildenafil, tadalafil, and vardenafil all block PDE5. Head-to-head, average IIEF-EF gains sit in the same band. None is a secret stronger pill for the typical man. The split is pharmacology. Tadalafil's 17.5-hour half-life, food-independence, and labeled daily 5 mg lane are the Bothell properties. Sildenafil is the longest-studied and usually the cheapest generic. Vardenafil sits on a short clock with a QT note of its own.
Sildenafil and vardenafil carry more PDE6 activity in the retina, which is why a minority see a temporary blue tinge. Tadalafil largely spares PDE6 and has some PDE11 activity whose clinical meaning is still thin. None of that touches the shared hard stop: no nitrates. The individual files are sildenafil and vardenafil. Pick a clock. Do not pick a slogan.
Post the points. Drop the slogan.
Cialis 20 mg PRN posted IIEF-EF gains near 8 points and SEP3 rates that held across a 36-hour span. Cialis 5 mg daily posted the same family of scores without an event clock, then added an IPSS drop for BPH. PHIRST posted 33 meters at 40 mg for a different disease. Those are the signals. A weekend nickname is a leftover from the half-life, not a trial row.
Against its siblings, tadalafil does not win on raw power. It wins on a clock you can live with. Never with nitrates. Change a strength or a lane only after your own clinician has the list. Elena's thread below is the human read of the same numbers.
Reader mail
Reader questions on this article
Answered by Dr. Elena Vasquez, MD · Urology & men's health
Readers asked how to read the scorecards. These traces are the ones I would post.
IIEF is a 15-item questionnaire. The part I score first is the erectile-function domain: six questions about frequency, firmness, penetration, maintenance, and confidence, totaling 6 to 30. Twenty-six or higher is the usual 'back to normal' cut. SEP2 and SEP3 come from a diary you keep after attempts. SEP2 is 'could you penetrate.' SEP3 is 'could you finish.' SEP3 is the harder bar and the one that usually fails first. GAQ is a single yes-or-no on whether the treatment helped. When all four move, as they did for Cialis 20 mg and for 5 mg daily, I trust the file more than a 36-hour slogan.
Is tadalafil actually better than Viagra, or just longer?
Mostly longer, and I mean that as useful, not as a slight. Average IIEF-EF gains across the three oral PDE5 inhibitors sit in the same band. Brock saw +7.9 on tadalafil 20 mg versus +0.6 on placebo. That is a real drug-placebo gap, not a win over sildenafil. What tadalafil uniquely posts is a 17.5-hour half-life, a 36-hour attempt window, no meaningful food effect, and a labeled 5 mg daily lane. If you want a clock that does not own the evening, that is the signal. If you want the cheapest, most-studied generic, sildenafil often wins that desk. Efficacy is close. Fit is not.
Will 5 mg daily fix my prostate or just mask it?
It will change how the symptoms feel. The 2011 program showed a meaningful IPSS drop on 5 mg daily against placebo, and in men who also had ED the same strip lifted IIEF-EF. I will be plain about the limit: tadalafil does not reliably raise measured peak flow and it does not shrink the gland. Alpha-blockers and 5-alpha-reductase inhibitors do different mechanical jobs. So 5 mg daily is a symptom treatment that can cover erections at the same time. If flow is the main complaint or the gland is large, we talk about other tools. We do not stack tadalafil on an alpha-blocker as a dual BPH plan.
Why should I care about PHIRST if I only want a 20 mg card?
You mostly should not, except as a caution against dose folklore. PHIRST-1 was a 16-week PAH trial. The 40 mg daily arm walked 33 meters farther than placebo in six minutes. That underpinned Adcirca, not Cialis. For a man on a 20 mg PRN card or a 5 mg daily strip, the lesson is that the same enzyme can do serious vascular work at a different dose in the lung. It is not a reason to chase 40 mg for erections. Different desk, different specialists, different monitoring. I keep those bottles apart on purpose.
Why the blue-tinge talk with some pills but not Cialis?
PDE6 lives in the retina. Sildenafil and vardenafil have more activity there, so a minority see a temporary blue or bright tinge that clears as the drug fades. Tadalafil is far more selective for PDE5 over PDE6 - on the order of 700-fold in the older ICOS figures - and visual complaints are uncommon. It does have some PDE11 activity. We still do not have a clean clinical story for that. If a visual tinge on another pill bothers you, a 20 mg Cialis card or a 5 mg daily strip is a reasonable switch to discuss. The nitrate hold does not change with the color of the tablet.
Which schedule has the better evidence, daily 5 mg or 20 mg PRN?
Both posted IIEF points. Neither is the thin file. The as-needed 10 and 20 mg stack is older and larger - Brock's five trials, Carson's eleven-trial update, Porst's timed window. The daily 2.5 and 5 mg lane has three phase 3 studies plus the later BPH program. I do not crown a scientific winner. I ask how often you have sex and whether you also have urinary symptoms. Frequent or dual ED-plus-BPH points to 5 mg daily. Occasional and prostate-quiet points to a 20 mg PRN card. The evidence supports both. The calendar picks one.
If the efficacy numbers are close, does the brand I pick even matter?
For raw IIEF-EF, less than the ads imply. For fit and safety, yes. I steer by clock, food, other medicines, and cost after 2018 generics. Tadalafil if you want a long window or a 5 mg daily strip. Sildenafil if you want the cheapest, most-studied short clock and can keep a fatty meal off the swallow. Vardenafil if a clinician has a reason to prefer that short profile and has checked the QT note. The brand does not secretly work better. The hold that never bends is the same on all three: no nitrates. That sentence outranks any preference survey.
What will a 5 mg daily receipt actually tell me?
Strength, quantity, and a pharmacy name. It will not tell you your IIEF-EF change or whether SEP3 moved. Those are clinic scores, not bag labels. Coupon copy that shouts 36 hours is a leftover from Porst, not a receipt line. After the 2018 generic lapse, cash prices vary by counter. Compare the same 5 mg daily count or the same 20 mg PRN count at a named US pharmacy. I will not invent a dollar figure. Bring the nitrate and CYP3A4 list before anyone prices either card.
I have diabetes. Do the trial points still apply to me?
They apply, with a humbler absolute rate. Diabetic ED was in the early stacks and in dedicated studies. The direction is the same: IIEF-EF and SEP3 move past placebo. The starting scores are often worse, so fewer men land at 26 or higher. That is not a reason to skip the class. It is a reason not to expect a magazine result. I still start from the labeled 10 mg PRN or 2.5-5 mg daily, then titrate. Diabetes also raises the chance that ED is a vascular flag. The tablet treats the erection. It does not treat the arteries. That conversation belongs in the same visit.
General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.
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