Maximum Dose of Tadalafil in 24 Hours

Quick Answer: The Maximum Safe Dose in 24 Hours

Why the 24-Hour Limit Exists (Half-Life & Duration)

Tadalafil leaves the body slowly—the mean terminal half-life is about 17.5 hours, and it can be longer in older adults. That pharmacokinetic profile means a substantial amount of drug is still on board the next day, so taking another tablet within 24 hours stacks exposure and increases risks like symptomatic hypotension or priapism. This is why labels and clinical references cap use at no more than once per day, even when the previous dose felt mild or timing wasn’t ideal. The prescribing information Pharmacokinetics section documents the half-life constraint (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ebddb745-81f9-4b25-8739-b2886032ed26#S12.3).

“Up to 36 hours” effect window and accumulation risk

Because concentrations decline slowly, many people experience a functional window up to 36 hours after a single dose. That flexibility is helpful for planning but also a reminder that adding a second dose too soon does not equal better efficacy—it just increases adverse-event risk. Standard references echo this duration and the associated frequency limit; see StatPearls for half-life and duration context (https://www.ncbi.nlm.nih.gov/books/NBK603743/).

Tadalafil Dosage Options (ED)

Two labeled strategies exist for ED: an as-needed (on-demand) tablet taken before sexual activity, or a once-daily regimen for people who prefer ongoing readiness or have frequent sexual activity.

As-needed dosing (PRN). Most adults start at 10 mg taken prior to anticipated sexual activity. Based on effect and side effects, clinicians may decrease to 5 mg or increase to 20 mg (the max single ED dose)—with the crucial rule of no more than one dose in 24 hours. This titration range and frequency cap are laid out under Dosing and Erectile dysfunction in standard references including the Mayo Clinic monograph and the Cialis label (https://www.mayoclinic.org/drugs-supplements/tadalafil-oral-route/description/drg-20067204 ; https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ebddb745-81f9-4b25-8739-b2886032ed26).

Once-daily dosing. If you want steady coverage, the labeled daily dose is 2.5 mg once daily, which may be increased to 5 mg once daily if needed. Do not add an extra “as-needed” tablet on top of the daily regimen; the daily plan already assumes continuous exposure. (Mayo Clinic “Dosing”; Cialis label “Erectile Dysfunction—Once Daily”).

Who starts lower? People who experience adverse effects at 10 mg, those with certain comorbidities, or those on interacting medicines often begin at 5 mg (or choose the 2.5–5 mg daily path). Your prescriber will reassess response and tolerability after several attempts before adjusting the dose.

How to Time Your Dose for Best Results

As-needed (ED) timing. Take tadalafil at least 30 minutes before sexual activity; many people find the 1–2 hour window reliable. Because the effect can last up to 36 hours, there’s no benefit to “topping up” later the same day. You may take it with or without food. See the Proper Use/Dosing guidance for these points on the Mayo Clinic page, which also reiterates the once-daily maximum (https://www.mayoclinic.org/drugs-supplements/tadalafil-oral-route/description/drg-20067204).

Alcohol and grapefruit. Keep alcohol light; combining tadalafil with substantial alcohol can amplify dizziness or low blood pressure. Avoid grapefruit and grapefruit juice, which inhibit CYP3A4 and can raise tadalafil levels—this interaction is flagged in consumer and professional monographs (https://medlineplus.gov/druginfo/meds/a604008.html).

Daily regimens. If you’re on once-daily tadalafil (2.5–5 mg), take it at the same time each day for steady levels, and do not add an extra tablet before sex.

Safety Guardrails: When Less Is More

One dose in 24 hours—no exceptions. Taking a second tablet within the same day adds exposure without improving efficacy and increases risks like symptomatic hypotension and priapism (an erection ≥4 hours requires urgent care). Standard references emphasize once-daily maximums and seeking emergency help for prolonged erections, even at usual doses. See “Precautions” in Mayo’s monograph (https://www.mayoclinic.org/drugs-supplements/tadalafil-oral-route/description/drg-20067204).

- Absolutely avoid nitrates. Combining tadalafil with any organic nitrate can cause a dangerous blood-pressure drop. Labels instruct clinicians to wait at least 48 hours after the last tadalafil dose before considering nitrates in an emergency, with close monitoring. Riociguat is also contraindicated with tadalafil. These prohibitions are explicit in the FDA-approved prescribing information (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ebddb745-81f9-4b25-8739-b2886032ed26#SContraindications).

- Blood-pressure medicines and alpha-blockers. Because tadalafil lowers vascular resistance, adding it to alpha-blockers or multiple antihypertensives can potentiate hypotension. Prescribers typically stabilize the alpha-blocker first, then start tadalafil at the lowest dose with careful follow-up.

Dose Adjustments & Special Populations

Kidneys (as-needed ED). For CrCl 30–50 mL/min, use ≤10 mg not more often than every 48 hours; for CrCl <30 mL/min or hemodialysis, ≤5 mg every 72 hours and avoid once-daily ED dosing. (Label: Dosage and Administration / Use in Specific Populations).

Liver. In mild–moderate hepatic impairment, do not exceed 10 mg once daily for on-demand ED; in severe hepatic disease, tadalafil for ED is generally not recommended.

CYP3A4 interactions. Strong inhibitors (e.g., ketoconazole, ritonavir): limit PRN to 10 mg no more than once every 72 hours, or ≤2.5 mg once daily if on daily regimen. Potent inducers (e.g., rifampin) may reduce efficacy (Label: Drug Interactions / Dosage).

Older adults & polypharmacy. Because half-life can be longer and BP effects additive, many clinicians start at the lowest dose and titrate cautiously, especially alongside alpha-blockers or multiple antihypertensives.

Comparing Max Doses: Sildenafil, Vardenafil, and Tadalafil

Across the three oral PDE5 inhibitors, the maximum single ED dose and maximum frequency align closely: sildenafil 100 mg, vardenafil 20 mg, and tadalafil 20 mg—each limited to one dose per 24 hours. Cleveland Clinic MedEd’s table lays these parameters side-by-side (https://www.clevelandclinicmeded.com/medicalpubs/pharmacy/marap2004/ed-table2.htm).

Choice often hinges on duration and onset: sildenafil and vardenafil tend to have a shorter window (roughly 4–8 hours), while tadalafil lasts longer (up to ~36 hours), supporting either on-demand flexibility or once-daily 2.5–5 mg regimens. See the AUA guideline for dose titration within labeled limits (https://www.auanet.org/guidelines-and-quality/guidelines/erectile-dysfunction-guideline).

Cialis Dosage Chart (ED, BPH, PAH)

- ED (as needed): Start 10 mg; adjust 5–20 mg. Max: one dose in 24 hours. (Mayo Clinic: Dosing) 
- ED (daily use): 2.5 mg → 5 mg once daily. (Cialis Prescribing Information) 
- BPH (± ED): 5 mg once daily at about the same time each day. 
- Renal/hepatic adjustments: Lower doses and extended intervals per label; daily ED dosing may be not recommended in severe renal impairment. 
- PAH (different indication/product): 40 mg once daily (two 20 mg tablets). Not an ED dose.

Disclaimer

Disclaimer: This website connects patients with licensed healthcare providers who can evaluate medical conditions and prescribe medications when appropriate. Some medications available through this service may be compounded drugs, which are customized formulations prepared by a pharmacy. The FDA does not conduct premarket review for compounded drugs to evaluate their safety, effectiveness, or quality. (See here: https://www.fda.gov/consumers/consumer-updates/it-really-fda-approved). Individual results may vary, and these medications should only be used under the guidance of a qualified healthcare professional. The information in this article is for educational purposes only and should not be considered medical advice. Always consult your healthcare provider before starting any new treatment.