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Probe · sildenafil · 3 min read

When does the Viagra label start at 25 mg?

Consider a starting dose of 25 mg in patients over 65 years, patients with hepatic impairment, and patients with creatinine clearance under 30 mL/min. Strong CYP3A4 inhibitors and erythromycin sit on the same consider-25 sentence. Ritonavir is stricter: 25 mg and not again for 48 hours. The usual start is still 50 mg when those rows are clean. This vault features both strengths.

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

Last reviewed

Updated

01How 50 mg is not for everyone over 65

Forest-green still life: smaller blue tablet on an older brass saucer

A clean 52-year-old list often starts at 50 mg. A 70-year-old on an alpha-blocker and a strong azole should not. Age is one consider-25 row, not the only one.

The dose-step pulse walks who stays at 25 mg on purpose.

02When the dose-rung pulse holds the rest of the list

Alpha-blocker starts and the honest 50 mg trial sit on the dose-step pulse and on Viagra next to an alpha-blocker.

Once those rows are read, 25 mg and 50 mg remain the featured band on the sildenafil 25-50 mg vault.

03What severe kidney clearance does

Mild (50-80 mL/min) and moderate (30-49 mL/min) clearance do not require a dose adjustment. Severe impairment (under 30 mL/min) roughly doubled Cmax and AUC. Consider 25 mg there.

A 50 mg 'for everyone' carton that never asks about creatinine is selling a count.

04How liver rows join that 25 mg start

Hepatic impairment, including cirrhosis, raised exposure (Child-Pugh A and B: Cmax +47%, AUC +85% in volunteers). Child-Pugh C was not studied. Consider 25 mg in any degree of hepatic impairment.

That is a start choice, not a new indication.

05When age 65 moves the start to 25

Administration in older men produced higher plasma levels. The insert says consider 25 mg. It does not say everyone over 65 is forbidden from 50 mg later.

The hour clock does not change. About one hour before sexual activity still applies to that 25 mg swallow.

06Why strong CYP3A4 sits on the same 25

Strong azoles, saquinavir, and erythromycin share a consider-25 mg line. Saquinavir or erythromycin raised sildenafil levels about three-fold. Ritonavir is its own cap: 25 mg and not again for 48 hours.

Ritonavir 25 mg, no repeat 48 h is that stricter row.

Sources

  1. DailyMed Viagra (sildenafil) prescribing information - Dosage 2.4-2.5; Use in Specific Populations 8.5-8.7.

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 label.

Soren E. I am 68 and healthy. Must I start at 25 mg?

Vault reply

The label says consider 25 mg over 65 because exposure is higher. It is a directed start, not a lifetime ban on 50 mg.

Camille B. CrCl 40. Do I need 25 mg?

Vault reply

Moderate impairment (30-49 mL/min) has no dose adjustment. The consider-25 kidney row is clearance under 30.

Raj P. Ketoconazole plus 50 mg - OK if I feel fine?

Vault reply

Consider 25 mg with strong CYP3A4 inhibitors. Feeling fine does not cancel that row.

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.