Where the nine locks were made
None of these nine arrived as a finished postcard. These are the labs that found them, the clinics that tested them, and the regulators that set the limits.
Pfizer, Sandwich (discovery site)
Ramsgate Road, Sandwich, Kent CT13 9NJ, United Kingdom
Sildenafil began here as UK-92,480, an angina candidate that disappointed on chest pain. Volunteers kept mentioning a side effect the programme had not asked for, and the work was redrawn around it. The Halo 100 mg ceiling lock still carries that cardiac history.
ICOS Corporation with Eli Lilly
22021 20th Avenue SE, Bothell, WA 98021, USA
Tadalafil was identified at this Washington biotech and carried through late trials with Eli Lilly. Slow clearance is why a 2.5 mg daily pack and a 20 mg weekend tablet are different locks on this desk, not two names for the same fill.
Bayer, Wuppertal
Aprather Weg 18a, 42113 Wuppertal, Germany
Wuppertal developed vardenafil, later sold as Levitra and the orodispersible Staxyn. Milligram for milligram it binds PDE5 more tightly than either sibling, which is why the Halo small-start lock sits at 2.5 mg.
Knoll / Flint laboratories (Synthroid lineage)
Historic Midwestern US manufacturing sites, later AbbVie
Levothyroxine sodium as Synthroid has a long US label trail. The Halo card locks 75 mcg on an empty stomach because coffee, calcium and a full breakfast move TSH more than most people expect.
Merck Sharp & Dohme (Stromectol)
Kitasato Institute collaboration; US label via Merck
Ivermectin reached a US tablet as Stromectol at 3 mg only. Halo counts those tablets at 150 mcg/kg for labelled parasites. A 6 mg or 12 mg tablet is not a US NDC on this desk.
U.S. Food and Drug Administration / DailyMed
10903 New Hampshire Avenue, Silver Spring, MD 20993, USA
The American regulator whose current prescribing information fixes the doses, boxed warnings and interaction rules we quote. Where a card here and the live FDA label diverge, the label is the authority - the nitrate contraindication above all.
Health Canada
Health Products and Food Branch, Ottawa, Ontario, Canada
Because the lens desk sits in Montreal, Canadian product monographs are opened beside the US label. When the two part ways on a dose or an indication, the card says so instead of quietly picking one.
Why the map still matters on a card
Sildenafil's start as a failed angina candidate is why a heart history still sits on every 100 mg note. Tadalafil's slow clearance out of Bothell is why a 2.5 mg daily pack and a 20 mg weekend tablet are different locks. Vardenafil's tightness at Wuppertal is why 2.5 mg is a small start, not a casual ceiling. Synthroid's TSH sensitivity is why 75 mcg stays on an empty stomach. Stromectol's US tablet is 3 mg only, counted at 150 mcg/kg. Each full card links back to the institution that shaped the molecule.