01The ladder is 25, 50, 100 - and most men start in the middle
| Rung | Who it is for |
|---|---|
| 25 mg start | ≥65 y, severe renal, hepatic impairment, many CYP3A4, alpha-blocker initiation |
| 50 mg start | Most adults without those flags |
| 100 mg step | After fair 50 mg trials; ceiling |
| Ritonavir special | 25 mg; do not exceed 25 mg in 48 h |
Three labeled film tablets: 25, 50, 100 mg. Most men start at 50. The step up is 100. The step down is 25. Frequency is once per day. That is the whole ladder. There is no 150, no same-night second tablet, and no "loading 100 then settle" ritual in the PI.
Halo's SERP lock is the 100 mg ceiling tablet. This note will name 50 and 25 because you cannot use a ceiling honestly without the rungs under it. Buying 100 mg first because a title mentioned it is not the same as being labeled for 100 mg.
Effect generally rose with dose in the RigiScan work, and so did some adverse events in the trial tables. More milligrams is not free. Headache, flushing, and dyspepsia are how the ladder collects its tax.
02What a fair 50 mg trial actually is
A fair trial is several attempts with sexual stimulation, modest alcohol, and a plate that is not a high-fat sabotage. One restaurant night at 40 minutes is not a trial. Read meal timing before anyone writes 100 mg.
Anxiety on the first tablet can fail a pharmacologically adequate dose. So can expecting an erection without arousal. So can a partner who is not in the room. Those are coaching problems. They do not become 100 mg problems just because the blister says 50.
If 50 mg works but flushing is miserable, the conversation is 25 mg or a molecule switch, not a stoic climb. If 50 mg is quiet on side effects and weak on erectile response after honest attempts, then 100 mg is the labeled next step.
Do not split 100 mg tablets into homemade 50s unless a pharmacist and prescriber agreed the specific product can be split. Many film coats are not scored for that job.
03When the next move is a different molecule, not 100 mg
If every failure is a late high-fat dinner, stay on 50 mg and fix the clock. If timer anxiety is the whole complaint, tadalafil daily 2.5 mg may fit better than a louder sildenafil night. If a QT history blocks vardenafil, that is a different note - do not use sildenafil 100 mg as a silent substitute without a visit.
Color-tinge and PDE6 talk belong in counseling at any dose. Men with retinitis pigmentosa need a specialist conversation before any PDE5, not a 100 mg experiment.
Compare class choices on the PDE5 contrast sheet. Steps stay inside one molecule until a clinician changes the molecule.
04Twenty-five milligrams is a start, not a slight
Age 65 or older: clearance falls; plasma AUC of sildenafil was about 84% higher in elderly volunteers. The label says consider 25 mg. That is exposure math, not ageism.
Severe renal impairment (CrCl under 30 mL/min) roughly doubles exposure. Hepatic impairment raised Cmax about 47% and AUC about 85% in studied Child-Pugh A/B volunteers. Child-Pugh C was not studied. Consider 25 mg.
Alpha-blockers: be stable on the alpha-blocker first, then start sildenafil at 25 mg. Strong CYP3A4 inhibitors and erythromycin: consider 25 mg. Ritonavir is stricter - 25 mg, and no more than 25 mg in 48 hours, because AUC rose about 11-fold.
A 65-year-old on ritonavir who starts at 100 mg because a Halo title mentioned 100 mg is reading marketing, not the PI. The lock is the ceiling for the domain, not a universal first tablet.
05Write the attempts down or the 100 mg step will be a guess
A useful 50 mg log has four columns: date, plate (light or heavy), minutes to start, and whether stimulation was real. Three restaurant failures with no home trials do not justify 100 mg. Three home trials on light plates with honest arousal do.
Headache and flush after 50 mg that the couple can live with are not reasons to skip 100 mg if erectile response was weak. Headache that cancels the night is a reason to step to 25 mg or change molecule. Toleration is the other half of the label sentence, not a footnote.
Visual color tinge is more often a counseling item than a stop. Sudden vision loss is a stop. Do not climb to 100 mg to "see if the blue edges go away" - they will not, and NAION talk belongs at any rung. Men with a crowded disc or prior NAION need a clinician, not a ceiling tablet.
Hearing change, even if brief, is a stop-and-call event. The PI lists sudden hearing loss across PDE5 drugs. A 100 mg step after a ignored tinnitus episode is the wrong stubbornness.
If the log shows 50 mg working two nights in three, stay. Chasing a perfect night with 100 mg because one anniversary failed is how flushing gets worse and the couple learns the wrong lesson about milligrams.
Bring the log to the same visit that reviews nitrates and alpha-blockers. Camille Rousseau reviews these notes. The prescriber who sees the log writes the step.
Hepatic impairment without a 25 mg start is the other common skip. Child-Pugh A/B already raised exposure in volunteers. Child-Pugh C was not studied. A ceiling tablet as a first night in that setting is not bold. It is unread labeling.
06One hundred milligrams is a stop sign as well as a step
- No 100 mg plus a second PDE5
- No 100 mg the same night as a failed 50
- No 100 mg first in ritonavir or unstable alpha-blockade
- Log attempts before the climb
100 mg is the maximum recommended dose. It is also once per day. Failed 100 mg after a heavy meal is still a meal problem. Failed 100 mg with nitrates in the drawer is a contraindication, not a titration.
Do not add tadalafil or vardenafil on the same day because 100 mg "almost worked." Class labels forbid combining PDE5 inhibitors or other ED therapies as a stack.
Sitting blood pressure in healthy volunteers fell about 8.3/5.3 mmHg after 100 mg. The drop was most notable around 1-2 hours and was not different from placebo at 8 hours. Nitrates make that drop dangerous. Food timing does not cancel it.
Priapism past four hours is an emergency at any rung. Sudden vision or hearing loss stops the drug. Those rules do not relax at 25 mg and do not get extra drama only at 100 mg. They apply to the class.
07Climb only after the trial is honest
50 mg is the usual start. 100 mg is Halo's locked ceiling and a labeled maximum after effect and toleration are known. 25 mg is the start for named groups. Once daily. No homemade rungs.
Dr. Camille Rousseau reviews the brief desk. Your clinician writes the actual step. Bring the meal log and the heart list to that visit.
A ceiling tablet in the title is not a first-night order. Treat 100 mg as a decision you can explain in one sentence: 50 mg had a fair trial, side effects were acceptable, and no special-population flag said 25. If you cannot say that sentence, stay on the current rung.
How to cite this page - Vancouver style
Halo Medix Lens Desk. Fifty milligrams first: the 100 mg ceiling is a later decision [Internet]. Montreal: Halo Medix; 21 August 2026 [cited 2026 Aug 21]. Available from: https://halomedix.com/notes/sildenafil-dose-steps/
Sources and how we reviewed this card
- FDA Viagra (sildenafil) labeling - 50 mg usual start, 25-100 mg range, special-population 25 mg, ritonavir 25 mg/48 h
- Halo Medix sildenafil brief and meal-timing note
Method in brief: clip from primary sources, cross against the current FDA label, lens read by Dr. Camille Rousseau, MD, then file with a dated review. Full walk-through on the method page and editorial standards.