Clinical pharmacology reference · HIM-000
How each drug works, when it works, the trial that mattered, and the interaction that hurts people — label facts without the forty-page slog. No checkout, no brand rankings.
Four shelves. Jump to the molecule you need — each guide keeps a stable HIM code for citations.
Same core pathway, different timing. How long each lasts, and how much food and side-effect texture vary, matters more than most patients expect.
Wakefulness, nerve pain, and muscle spasticity — three different mechanisms and three different monitoring plans. Not interchangeable.
An everyday oral antibiotic, an antiparasitic clouded by controversy, and a prokinetic with a regulatory gap in the US.
A loop diuretic whose oral dose fails exactly when patients are sickest, and an oral steroid whose whole safety story is duration.
Four reads for questions that span a whole class, not just a single pill.
The nitric-oxide to cGMP pathway, why the pills need arousal, and why nitrates are a hard stop.
Read topic → HIM-014Why the penile arteries clog before the coronary ones, and what a new ED complaint should prompt you to check.
Read topic → HIM-015Fitness, sleep, hidden drug culprits, hormones, and the mind — the causes a tablet cannot fix.
Read topic → HIM-004Bioequivalence, AB ratings, and why a cheap online 'generic' is a different risk category entirely.
Read topic →When someone asks what their new pill does, they want four things: how it helps, how fast, the dose their neighbor probably got in the trial, and the side effect worth calling about. That is what each guide delivers — without making you download the full prescribing PDF.
No drug-company money and nothing for sale. Brand names appear only so you know which molecule we mean, never as a recommendation.
We start with the live FDA label — doses, warnings, the pharmacokinetics — then read the trials it cites. Data grids and timelines appear only when they save you from doing arithmetic in your head.
Where a drug is used differently around the world, we say so plainly. Domperidone is the obvious case: dispensed widely abroad, not approved in the US at all.
Label updates take precedence the day they publish. These guides explain the label in friendlier language; your clinician still writes the prescription.
Each drug guide runs the same path: what it is, how it works, its timing, the trials, dosing, interactions, side effects, special situations, practical counseling, and a bottom line.
Four reads handle questions bigger than a single tablet — how the ED drugs work as a class, what an FDA-approved generic actually guarantees, why ED is an early heart warning, and the causes a pill cannot fix.
Drugs live under /medications/. Class topics under /health-topics/. Legal under /legal/.
Every guide carries a stable HIM code, so a citation in a syllabus or slide deck will not rot when we refresh a number.
| Drug | Brand | Roughly how long it lasts | Food matters? | HIM |
|---|---|---|---|---|
| Sildenafil | Viagra | a few hours | yes — fatty meal delays it | 001 |
| Tadalafil | Cialis | over a day | no | 002 |
| Vardenafil | Levitra | a few hours | yes | 003 |
| Modafinil | Provigil | most of a day | minor | 006 |
| Gabapentin | Neurontin | hours (kidney-dependent) | no | 011 |
| Furosemide | Lasix | a couple of hours | no | 008 |
We cite the trials behind approval and keep the placebo response in view — in ED studies it is large, and ignoring it makes the numbers look prettier than the clinic feels.
Domperidone is used in many countries and is not FDA-approved here. We say that up front. Its heart-rhythm risk applies wherever it is sold.
HIM-001 through HIM-015 — stable IDs for syllabi, slide decks, and citations that will not break.
Furosemide makes the kidneys dump salt and water, which is exactly what you want when fluid is backing up into the lungs and legs. It is one of the most useful …
Ivermectin is a genuinely important antiparasitic that has treated hundreds of millions of people for river blindness, scabies, and intestinal worms. At human d…
Tadalafil uses the same arousal pathway as other PDE5 pills, but it stays in your system far longer. That changes how you plan sex - and opens a low daily dose …
An erection is not magic and not purely in your head - it is blood vessels relaxing and filling under a chemical signal. Once you see that chain, the pills make…
Gabapentin calms overexcited nerves, which makes it useful for nerve pain and some seizures. Its name suggests it mimics the calming chemical GABA; it does not,…
Sildenafil does not switch an erection on. During arousal your body makes a messenger called cGMP; the tablet slows the enzyme that destroys it so blood can sta…
For a lot of men, erectile dysfunction is not really a sexual problem first - it is the earliest visible sign that the blood vessels are in trouble. The small a…
Amoxicillin is the reliable oral antibiotic clinicians reach for when the likely bug is still susceptible. It absorbs well, is well tolerated, and kills by brea…
Vardenafil looks strongest on paper in lab comparisons. In real clinics, at labeled doses, it behaves much like sildenafil - potency differences matter less tha…
PDE5 pills are good at rescuing the moment. They are useless at fixing the reasons erections faded in the first place - and those reasons are often things a pre…
Prednisolone is a powerful anti-inflammatory steroid used everywhere from childhood asthma flares to autoimmune disease. Unlike prednisone, it is already in its…
Tizanidine loosens tight, spastic muscles by turning down the nervous system signals that keep them clenched, rather than acting on the muscle directly. It work…
Modafinil keeps people awake at normal doses without delivering the full stimulant hit of an amphetamine. It is genuinely useful for real sleep disorders and, i…
When a patient asks why brand Cialis costs a fortune while online 'generic tadalafil' costs pennies, the answer is not really about the molecule. It is about th…
Domperidone speeds up a sluggish stomach and calms nausea by blocking dopamine, but mostly outside the brain - so it causes far fewer of the movement and mood s…
We do not sell drugs and we take no sponsorship. Names identify molecules, nothing more.
Check the live label and talk to the patient's own clinician before changing anything. Reading here does not create a doctor-patient relationship.