Clinical reference · HPH-000
HPH ward cards on sildenafil, tadalafil, vardenafil, and eight systemic drugs. Mechanism, PK, trials. We do not sell tablets.
Four shelves. Jump to the molecule you need — each guide carries a stable HPH code for citations.
Same cGMP pathway, different half-lives. Meal timing and side-effect texture vary more than most patients expect.
Wakefulness, neuropathic pain, spasticity — three mechanisms, three monitoring plans. Don't treat them as interchangeable.
Outpatient beta-lactams, antiparasitics, and a peripheral prokinetic with a regulatory gap in the U.S.
Loop diuretic kinetics in decompensated heart failure. Oral steroid tapers residents still botch.
For questions bigger than one tablet strength.
Why PDE5 drugs need arousal, why nitrates stay off the table, and where vascular comorbidity fits.
Read topic HPH-004ANDA bioequivalence, Orange Book AB ratings, and why Kamagra/Cenforce aren't U.S. generics.
Read topicWard rounds don't pause for 30-page prescribing information. We strip each label down to what you'd look up mid-shift: mechanism, half-life, the pivotal trial endpoint, dose ceiling, and the boxed warning that changes your order.
No pharma money. Viagra and Provigil show up only so you know which molecule we mean — not as a recommendation.
Pharmacy students, residents, pharmacists, anyone who prescribes these enough to need a refresher but not enough to carry the PI in their head.
Start with the live FDA label — doses, boxed warnings, PK tables — then pull the registration trials it cites. ADME grids and timelines only when they'd save you from doing the math on a napkin.
Off-label use overseas gets a line when it matters. Domperidone is the obvious one: dispensed in plenty of countries, not approved here.
FDA posts a label supplement tomorrow? The PDF wins. These pages are a map, not the contract.
Drug guides run intro → mechanism → PK → trials → dosing → interactions → adverse effects → special populations → bottom line. HPH-004 and HPH-005 handle class questions — generics, pathway — instead of one tablet strength.
Cite the HPH code in coursework. Related links at the bottom are suggested reading, not prescribing advice.
Drugs under /medications/. Class topics under /health-topics/. Legal under /legal/.
Long guides use a horizontal section jump bar — not the sidebar TOC some other reference sites use.
| Drug | Brand | t½ (approx.) | Food | HPH |
|---|---|---|---|---|
| Sildenafil | Viagra | 4 h | High-fat ↓ Cmax | 001 |
| Tadalafil | Cialis | 17.5 h | Minimal | 002 |
| Vardenafil | Levitra | 4–5 h | High-fat ↓ Cmax | 003 |
| Modafinil | Provigil | 12–15 h | Minor delay | 006 |
| Gabapentin | Neurontin | 5–7 h | None meaningful | 011 |
| Furosemide | Lasix | 1–2 h | None | 008 |
ED block: HPH-005 pathway first, then any of HPH-001–003, finish with HPH-004 on generics.
Sleep week: HPH-006. ID block: HPH-009 then HPH-013.
Eleven drug guides, two class topics. PDE5 drugs for ED. Modafinil, gabapentin, tizanidine for CNS and spasticity. Domperidone with its U.S. regulatory hole spelled out. Furosemide, amoxicillin, prednisolone, ivermectin for the rest of outpatient practice.
Every file gets an HPH code. Footer links cluster related science — that's reading order, not a swap chart.
| HPH ID | Guide | Type |
|---|---|---|
| HPH-001 | Sildenafil | Drug |
| HPH-002 | Tadalafil | Drug |
| HPH-003 | Vardenafil | Drug |
| HPH-004 | PDE5 generics (FDA) | Topic |
| HPH-005 | ED pathway | Topic |
| HPH-006 | Modafinil | Drug |
| HPH-007 | Domperidone | Drug |
| HPH-008 | Furosemide | Drug |
| HPH-009 | Amoxicillin | Drug |
| HPH-010 | Tizanidine | Drug |
| HPH-011 | Gabapentin | Drug |
| HPH-012 | Prednisolone | Drug |
| HPH-013 | Ivermectin | Drug |
Short cross-links — full PK lives in each HPH guide.
Oral PDE5 drugs are still first-line for ED where they're approved. Same cGMP pathway; different half-lives, different meal sensitivity.
Students memorize IC50 rankings like they're board questions. Labeled doses converge for most men anyway — exposure and protein binding matter as much as potency on a slide.
Nitrates stay contraindicated for the whole class. A 17-hour half-life doesn't make that negotiation easier.
Modafinil keeps people awake without full amphetamine signaling at usual doses. Mechanism is still messy — DAT inhibition, hypothalamic circuits, pick your favorite paper.
Gabapentin and tizanidine land in the same clinic notes but share almost nothing pharmacologically. Alpha-2-delta binding vs central alpha-2 agonism. Renal dose adjustment vs CYP1A2 traps.
Amoxicillin still works PO when the bug cooperates. Time above MIC drives killing — not peak height.
Ivermectin dosing shifts by indication; scabies is weight-based. Veterinary paste is a concentration gamble nobody should take.
Furosemide oral absorption falls apart in bad heart failure. Prednisolone tapers after long courses — HPA suppression isn't a lecture slide, it's real.
Motilium is familiar globally and missing from U.S. FDA approval. Peripheral D2 blockade, QT risk, azole interactions — all still apply wherever it's dispensed.
Health Pharmacology is a reference shelf, not a marketing site. We track mechanisms and numbers — not which manufacturer paid for the banner ad.
HPH codes stay fixed when facts update. Your citations shouldn't break because we fixed a half-life.
We refresh numbers when labels change. HPH IDs stay put.
No ads. No affiliate checkout. No 'ask your doctor about Brand X' copy.
We cite the trials behind approval — IIEF for PDE5, MWT for modafinil, Ashworth for tizanidine. Placebo response in ED studies is massive; skip it and the numbers lie prettier than clinic feels.
Domperidone gets used in many countries and isn't FDA-approved here. We say that upfront. QT risk with macrolides and azoles still applies wherever it's sold.
HPH-001 through HPH-013 — stable IDs for syllabi, slide decks, and citations that won't rot.
Fasted Tmax near 60 minutes is the first timing fact this ward card keeps for sildenafil (Viagra) 50 mg. A high-fat meal slides it later. Generic cost after a p…
Half-life near 17.5 hours is what daily Cialis 5 mg actually buys. Food matters less than with sildenafil. Generic tadalafil dropped cash cost; it did not drop …
Fifteen percent oral bioavailability is why Levitra 10 mg meal notes sit next to the QT line. A high-fat meal delays the peak. Generic vardenafil dropped cash c…
Maintenance of Wakefulness Test latency can rise on Provigil 200 mg while sleep debt stays. Those gains do not replace sleep hours, CPAP for apnea, or backup co…
QT homework comes before any Motilium blister, compounded tablet, or cross-border pack lands in the chart. Macrolides, hypokalemia on loop diuretics, and doses …
Overnight pounds, not reflex milligram doubles, decide whether a 40 mg Lasix tablet is working. Two pounds overnight, hypokalemia with digoxin, and PO Lasix tha…
Free drug hours above MIC decide whether generic Amoxil 500 mg is doing its job. Beta-lactam killing needs coverage for most of the interval, not a high peak; w…
Dosage form on the script is the first PK trap before any 4 mg Zanaflex titration. Ciprofloxacin and fluvoxamine are contraindications, not dose adjustments; fo…
LAT1 transporters cap how much of a 300 mg Neurontin swallow actually lands. Split doses beat a 1200 mg once-daily dump; renal dosing is mandatory because the d…
Eleven-hydroxylation already happened, so 5 mg prednisolone is not a prednisone order. Prelone 15 mg/5 mL read as teaspoons, abrupt stop after six weeks, and st…
Kilograms on the scale, not bathroom pounds or horse paste, set a Stromectol 3 mg count. 200 mcg/kg uses body weight in kg, scabies needs day-14 repeat, and hor…
Licensed AB tablets and no-NDC mail packs are not the same object. An AB-rated generic sildenafil, tadalafil, or vardenafil tablet passed 80-125% bioequivalence…
Nitric oxide has to show up before sildenafil, tadalafil, or vardenafil can prolong cGMP. They do not invent the signal. A tablet on a quiet couch does nothing …
We don't sell drugs and we don't take sponsorship. Names identify molecules.
Check the live label. Talk to the patient's clinician before you change anything.
Browsing here doesn't create a doctor–patient relationship.