How a 5 mg daily Cialis card gets priced
A nickname is not a price. The desk that matters is the one that turned a 17.5-hour half-life into two labeled cards a man can actually fill.
Patients and French papers coined 'Le Weekend' after a 36-hour response window, not after a marketing brief. That window is a pharmacokinetic leftover: roughly a quarter of a 20 mg dose is still on board at 36 hours. The US label never sold a weekend. It sold as-needed 5, 10, and 20 mg after November 2003, then a once-daily 2.5 and 5 mg lane in January 2008. The SERP lock on this site is the pair that still gets asked for: 5 mg daily or a 20 mg PRN card.
Pricing follows the card, not the rumor. A 20 mg tablet taken on a Friday can cover a quiet weekend without a second swallow. A 5 mg daily strip covers a busy week without a clock. Generic tadalafil after the 2018 US patent lapse collapsed the old brand premium, so the choice is no longer 'can I afford daily.' It is which calendar you actually live. The molecule file sits in the tadalafil reference. Do not invent a dollar figure from a screenshot. Ask the pharmacy that will fill the script.
Bothell, not Indianapolis: IC351 on a small bench
ICOS Corporation sat in Bothell, Washington, a 1989 biotech chasing cell-signalling enzymes, not a men's-health franchise. Phosphodiesterases were one family on that bench. Catalog IC351 blocked phosphodiesterase type 5 with a selectivity the chemists liked, and it lingered. That linger is the whole later business.
Glaxo Wellcome had an earlier partnership with ICOS from 1991. It lapsed in 1996 when the pipeline did not match Glaxo's core markets. ICOS kept the compound. Phase 1 work on IC351 started in 1995. Phase 2 in men with erectile dysfunction opened in 1997, after Pfizer's 1998 sildenafil launch had already proved the enzyme was a real target. A second entrant had to be different. Duration was the difference they already had.
Glaxo walked. Lilly stayed.
A small bench can find a molecule. It cannot run global phase 3, write a worldwide label, and staff a sales force. That is the joint-venture ping.
Eli Lilly and ICOS formed Lilly ICOS LLC in 1998. ICOS brought IC351 and the early science. Lilly brought trial scale, regulatory muscle, and a global desk. The generic name tadalafil and the brand Cialis were filed with the NDA around 2000-2001. The FDA asked for more confirmatory pharmacology and manufacturing work; the companies sent the extra package in 2003.
Europe cleared tadalafil in late 2002. The US nod landed on 21 November 2003, the third oral PDE5 inhibitor after sildenafil and vardenafil. Paul Clark, then ICOS chief, called it the first chapter of a research shop becoming a product shop. Lilly bought ICOS outright in 2007 for about $2.3 billion and folded the franchise in-house. The name on the bottle is Lilly's. The discovery address is still Bothell.
Half-life 17.5 hours is the whole price tag
Terminal half-life is about 17.5 hours in healthy men and about 21.6 hours in older men. Sildenafil and vardenafil sit near 4 hours. That gap is not a potency story. It is a clock story. Porst and colleagues showed a usable response out to 36 hours. Brock's 2002 integrated analysis of five randomized trials is what the 20 mg weekend card actually stands on, not a slogan.
Median time to peak is about 2 hours. Some men report an effect by 30 minutes. Counseling a 15-minute onset as reliable is a miss - fewer than 40 percent of attempts succeed that early. Food does not blunt tadalafil the way a fatty meal blunts sildenafil. Take the 20 mg card with dinner or without. The enzyme block still needs sexual stimulation. A long half-life is not a constant erection. It is a longer interval in which a real signal can land.
November 2003: the 20 mg weekend card
The first US label started most men at 10 mg as needed, with 20 mg if 10 mg was thin and 5 mg if metabolism or other drugs required a cut. Not more than once a day. The 20 mg tablet is the card this desk still posts for a weekend, because that is the strength men ask for when they want one swallow and a long window. The 10 mg start is still the labeled default for a first as-needed try.
One hold was locked on day one and has never loosened. Any organic nitrate - tablets, sprays, patches, long-acting pills, or recreational nitrites - is an absolute contraindication. Both drugs drive the same downstream relaxation. Stack them and blood pressure can fall to a dangerous, sometimes fatal level. After a tadalafil dose the label wants at least 48 hours before emergency nitrate is even considered, and then only under close monitoring. That hold is longer than the short-acting cousins because the half-life is longer. Tell every clinician you take it. The regulator's own language is on the FDA site and the current tablet file is on DailyMed for Cialis.
January 2008: the 5 mg daily strip
A long half-life does a second job once you stop thinking in events. It holds a low steady level if you swallow a small tablet every morning.
On 8 January 2008 the FDA cleared Cialis 2.5 mg and 5 mg for once-daily use in erectile dysfunction. Three phase 3 randomized, double-blind, placebo-controlled studies backed that lane. Men took the tablet without tying it to a planned encounter. The 5 mg daily strip is the SERP twin of the 20 mg weekend card on this site. Start daily at 2.5 mg if you need a gentler climb; 5 mg is the usual working daily dose when the gut and the head tolerate it.
Lilly's own note at the time said daily use may fit men who expect sex about twice a week or more. That is still a fair calendar split. Daily is not stronger. It is present. The trial read and the IIEF points live in the Cialis trial-signal post. The calendar choice itself is the daily-versus-PRN split.
Same molecule, two later desks: BPH and Adcirca
ICOS founded in Bothell, Washington, working cell-signalling enzymes including phosphodiesterases.
Glaxo Wellcome partnership; it lapses. ICOS keeps IC351.
Phase 1, then phase 2 in men with ED.
Lilly ICOS LLC formed to develop and market the compound.
FDA approves Cialis for ED as needed (5, 10, 20 mg). Europe had cleared it in 2002.
Lilly buys ICOS for about $2.3 billion.
Once-daily 2.5 mg and 5 mg cleared for ED.
Adcirca 40 mg daily cleared for PAH after PHIRST.
Daily 5 mg added for BPH and for ED plus BPH.
PDE5 also sits in prostate and bladder-neck smooth muscle. Blocking it eases lower-urinary symptoms of benign prostatic hyperplasia. In October 2011 the FDA added once-daily 5 mg for BPH signs and for men who carry both BPH and ED. Only the 5 mg daily dose holds those two extra indications. A 20 mg PRN card will not treat the night-time trips. That is a steady-level job.
The same enzyme sets tone in pulmonary arteries. In May 2009 tadalafil 40 mg once daily - two 20 mg tablets, branded Adcirca - was cleared for pulmonary arterial hypertension after PHIRST-1 showed a 33-meter gain in six-minute walk against placebo. United Therapeutics licensed the US PAH desk from Lilly in late 2008. Different brand, different dose, different specialists. Do not borrow an Adcirca bottle for a weekend card, and do not treat a lung-pressure clinic as a Cialis refill.
Where a 20 mg weekend Cialis fill is actually posted
A fill is a licensed US pharmacy, not a banner. This desk does not stock a cart. If you want a 20 mg PRN card or a 5 mg daily strip, the script goes to a pharmacy your clinician can name - a chain counter, an independent, or a mail-order bench that already holds your other medicines. GoodRx and similar coupon desks can show a cash range. They are not the store. The href on a row should be that chain's own pharmacy page, not a coupon domain pasted onto someone else's name.
Sildenafil and vardenafil are shorter clocks, not cheaper substitutes you swap without a new look at nitrates, alpha-blockers, and CYP3A4 inhibitors. Those two files sit at sildenafil and vardenafil. Tadalafil's food-independence and daily lane are the Bothell properties that still price the card. A patient-level walk-through of class warnings is on MedlinePlus.
What the Bothell file still flags
CYP3A4 inhibitors raise exposure. On a PRN card the labeled ceiling with a potent inhibitor such as ketoconazole or ritonavir is 10 mg, not more than once every 72 hours. On a daily strip the ceiling is 2.5 mg. Inducers such as rifampin can hollow out a daily 5 mg until it looks like a missed dose. Severe hepatic impairment and creatinine clearance under 30 mL/min are poor ground for the daily lane.
Alpha-blockers need a stable dose and a caution, not a second hypotensive stacked on top to treat BPH. Tadalafil 5 mg daily is approved as monotherapy for BPH symptoms. Combining it with an alpha-blocker as a dual BPH plan is the miss the label warns about. Back pain and myalgia often land 12 to 24 hours after a dose and fade within 48 hours. That delayed ache is a tadalafil signature, not a kidney stone until proven otherwise.
Post: one property, two priced cards
Bothell did not invent a stronger PDE5 blocker. It priced a longer one. The 20 mg weekend card and the 5 mg daily strip are the same half-life aimed at two calendars. Lilly scaled it. The later BPH and PAH desks are the same enzyme in other rooms. The slogan is optional. The 48-hour nitrate hold is not.
If you came for a story about a weekend, leave with a file: IC351, 17.5 hours, 21 November 2003, 8 January 2008, then 2011 for the prostate. Change a dose or a schedule only after your own clinician has the full list. The disclaimer on this site is the legal line. Elena's thread below is the human one.