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Probe · fildena · 3 min read

Does ritonavir change a Fildena 100 mg swallow?

Yes. Ritonavir changes the swallow. Coadministration raised sildenafil AUC about 11-fold on the US Viagra file. The labelled cap is then a single 25 mg dose in a 48 hour period. A Fildena 100 mg stamp is the wrong first ask on a boosted regimen. Other strong CYP3A4 blockers (ketoconazole, itraconazole, erythromycin, saquinavir) argue a 25 mg start. They do not all write the same 48-hour cut. The clinician who manages the antiviral rewrites the strip.

Medically reviewed by Dr. Mateo Ruiz, MD - Clinical pharmacology, Barcelona

Last reviewed

Updated

01How far does ritonavir raise sildenafil exposure?

Forest-green still life: tiny repeat gap, large tablet held back

About 11-fold for AUC. Cmax rose about 4-fold in the same interaction work. At 24 hours, plasma sildenafil was still about 200 ng/mL with ritonavir versus about 5 ng/mL when sildenafil was given alone.

Those leftover nanograms are why a next-morning 100 mg is a bad idea on a boosted regimen.

02What repeat interval does the US file write after ritonavir?

Do not exceed a maximum single dose of 25 mg of Viagra in a 48 hour period. That is the ritonavir row. It is stricter than the ordinary once-a-day cap.

The once-a-day probe is the ordinary cap. Do not mix the two calendars.

03Does ritonavir change a Fildena 100 mg swallow?

It does, if the unit is sildenafil. The boost is on the salt. Fortune art does not escape CYP3A4. Healthy-volunteer work used ritonavir 500 mg twice daily with a single 100 mg sildenafil dose.

High systemic levels in other work (200 to 800 mg sildenafil) were tied to low blood pressure, syncope, and prolonged erection. That is why the file cuts the milligram.

04Who should rewrite the strip before the next swallow?

The clinician who already manages the ritonavir. Bring the Fildena photo so they can see the 100 mg stamp. Then fill listed 25 mg if sildenafil is still appropriate and nitrates are absent.

This inbox will not clear a boosted regimen by email.

05Which other strong CYP3A4 blockers argue the milligram down?

Ketoconazole, itraconazole, erythromycin, and saquinavir. The file says consider a 25 mg start. That is a start cut, not the ritonavir 48-hour sentence.

Do not turn this paragraph into a full CYP catalog. One interacting antiviral is enough work for this probe.

06Is 100 mg still a sane first ask on a boosted regimen?

No. The export stamp is a ceiling for most men without ritonavir. With ritonavir the labelled ask is 25 mg, and not again before 48 hours.

A US window can fill listed 25 mg sildenafil. It will not pull a Fortune 100 to 'make up' the boost.

Sources

  1. DailyMed VIAGRA (sildenafil citrate) (ritonavir: 11-fold AUC; 25 mg in 48 hours).
  2. Qivana sildenafil 25-50 mg vault.

Checked against the current label and reviewed by Dr. Mateo Ruiz. See Probe, Assay, Glow-check, Seal.

Vault consult

Answers follow the U.S. Viagra (sildenafil) label for the INN; Fildena is an export carton name.

Celine W. I take ritonavir. Can I keep Fildena 100 on Friday nights?

Vault reply

No. The US file caps sildenafil at 25 mg in 48 hours with ritonavir. A 100 mg export stamp is the wrong ask. See the sildenafil 25-50 mg vault.

Rafi M. How big is the exposure jump?

Vault reply

AUC jumped roughly eleven times. Cmax was about four times higher. At 24 hours, levels were still about 200 ng/mL versus about 5 ng/mL alone.

June K. Ketoconazole too - same 48-hour rule?

Vault reply

Ketoconazole argues a 25 mg start. The 48-hour sentence is the ritonavir row. Do not copy the antiviral calendar onto every CYP3A4 drug.

Before you start, stop, or change any medicine, speak with your prescriber or pharmacist - they hold your chart, this vault card does not. Open the vault disclaimer.