Tadalafil Dosage: Doses, Daily Limit and Adjustments

PrescribedRX is a telehealth platform; prescriptions are written by licensed clinicians and filled by licensed partner pharmacies.

Short answer: For as-needed use in erectile dysfunction (ED) treatment, the Cialis prescribing information lists a starting tadalafil dosage of 10 mg, which may be raised to 20 mg or lowered to 5 mg, and states: “The maximum recommended dosing frequency is once per day in most patients” (Cialis 2.1). For once-daily use, it lists 2.5 mg, which may be raised to 5 mg (Cialis 2.2). The prescribing information lists lower limits for kidney or liver impairment and some interacting drugs, and your provider sets the dose.

Below, “Cialis 2.6” means section 2.6 of the Cialis prescribing information on DailyMed, revised 3/2026. Every dose on this page comes from the prescribing information and is not dosing advice.

What tadalafil doses does the Cialis prescribing information list?

Section 2 of the prescribing information lists doses by use (Cialis prescribing information, section 2):

Use	Starting dose listed	Range or limit	How often	Section
ED, as needed	10 mg, before expected sexual activity	May be raised to 20 mg or lowered to 5 mg	Maximum once per day for most patients	2.1
ED, once daily	2.5 mg	May be raised to 5 mg	Once a day at about the same time, regardless of sexual activity	2.2
Enlarged prostate (BPH)	5 mg	With finasteride to start BPH treatment: 5 mg a day for up to 26 weeks	Once a day at about the same time	2.3
ED and BPH together	5 mg	Not stated	Once a day at about the same time	2.4

The prescribing information also says Cialis may be taken without regard to food (Cialis 2.5).

What is the maximum dose of tadalafil in 24 hours?

For ED taken as needed, the Cialis prescribing information says the 10 mg starting dose “may be increased to 20 mg or decreased to 5 mg, based on individual efficacy and tolerability,” so 20 mg is the highest as-needed dose it lists. On frequency it says: “The maximum recommended dosing frequency is once per day in most patients.” Its highlights put it as “Not to be taken more than once per day” (Cialis 2.1). For once-daily use, the highest dose it lists is 5 mg (Cialis 2.2).

It sets lower limits for some groups, covered in the next two sections:

• Moderate kidney impairment: a maximum of 10 mg, no more than once every 48 hours, when used as needed (Cialis 2.6).
• Severe kidney impairment or hemodialysis: a maximum of 5 mg, no more than once every 72 hours, when used as needed (Cialis 2.6).
• Mild or moderate liver impairment: “The dose should not exceed 10 mg once per day,” when used as needed (Cialis 2.6).
• Potent CYP3A4 inhibitors such as ketoconazole or ritonavir: a maximum of 10 mg, no more than once every 72 hours, as needed, or 2.5 mg for once-daily use (Cialis 2.7).

Is there a 40 mg tadalafil dose?

Not in the Cialis prescribing information, whose highest listed dose is 20 mg (Cialis 2.1). A 40 mg dose appears in the prescribing information for Adcirca, a different tadalafil product indicated for pulmonary arterial hypertension (PAH, WHO Group 1). The Adcirca prescribing information lists 40 mg once daily, taken as two 20 mg tablets, and says dividing the 40 mg dose over the day is not recommended (Adcirca prescribing information).

How is the dose adjusted for kidney or liver problems?

Section 2.6 lists these adjustments. Kidney function is given as creatinine clearance (CrCl), a measure from a blood test. Liver function is given as Child-Pugh class, where A is mild, B is moderate and C is severe (Cialis 2.6).

Condition	As needed for ED	Once daily
Kidney: CrCl 30 to 50 mL/min	Start at 5 mg, no more than once a day; maximum 10 mg no more than once every 48 hours	BPH or ED and BPH: start at 2.5 mg
Kidney: CrCl under 30 mL/min or on hemodialysis	Maximum 5 mg, no more than once every 72 hours	Not recommended
Liver: Child-Pugh A or B	No more than 10 mg a day	Use with caution; not extensively evaluated
Liver: Child-Pugh C	Not recommended	Not recommended

Source: Cialis prescribing information, section 2.6. Your provider sets the dose.

Which medicines change the tadalafil dose?

Section 2.7 of the prescribing information covers medicines taken at the same time (Cialis 2.7):

• Nitrates: use with Cialis is contraindicated (Cialis 2.7; Cialis 4.1). Where a nitrate is deemed medically necessary in a life-threatening situation, it says “at least 48 hours should have elapsed after the last dose of CIALIS” (Cialis 5.1).
• Alpha-blockers and blood pressure medicines: section 2.7 gives prescribers separate starting-dose instructions for men already taking an alpha-blocker (Cialis 2.7). Whether tadalafil is appropriate with any blood pressure medicine is decided by a licensed provider who reviews your health history and current medications.
• Potent CYP3A4 inhibitors such as ketoconazole and ritonavir: as needed, a maximum of 10 mg no more than once every 72 hours; once daily, a maximum of 2.5 mg (Cialis 2.7).
• Rifampin: the prescribing information reports that rifampin 600 mg a day cut exposure to a 10 mg tadalafil dose by 88%. It says no dose adjustment is warranted, but that the efficacy of once-daily Cialis may be reduced by an unknown amount (Cialis 7.2).
• Alcohol: the prescribing information says “substantial consumption of alcohol (e.g., 5 units or greater)” with Cialis can raise the chance of dizziness, a drop in standing blood pressure, faster heart rate and headache (Cialis 5.9).

MedlinePlus says to tell your doctor and pharmacist about all prescription and nonprescription medicines, vitamins and supplements you take, and names alpha blockers and medications for high blood pressure (MedlinePlus: tadalafil). The AUA guideline lists anti-hypertensives among medicines that “potentially can interact with or influence the metabolism of PDE5i” (AUA guideline).

How long does a tadalafil dose last?

The Cialis prescribing information gives tadalafil a mean terminal half-life of 17.5 hours (Cialis 12.3), and its patient leaflet says some of a single dose stays in the body for more than 2 days (Cialis leaflet). For as-needed use, it says efficacy was shown up to 36 hours after dosing (Cialis 2.1).

The AUA guideline lists tadalafil as starting in 60 to 120 minutes and lasting up to 36 hours (AUA guideline, Table 3). By comparison, the Viagra prescribing information gives sildenafil a half-life of about 4 hours (Viagra 12.3). For more on how the two drugs differ, see how sildenafil and tadalafil differ.

When should you get medical help?

The Cialis prescribing information lists these warnings in section 5:

• Symptoms during sex: patients with symptoms when starting sexual activity “should be advised to refrain from further sexual activity and seek immediate medical attention” (Cialis 5.1).
• An erection lasting more than 4 hours: patients, “whether painful or not, should seek emergency medical attention” (Cialis 5.3).
• Sudden loss of vision in one or both eyes: it tells physicians to advise patients to stop all PDE5 inhibitors and seek medical attention (Cialis 5.4).
• Sudden decrease or loss of hearing: it says to stop the drug and seek prompt medical attention (Cialis 5.5).

Side effects are covered in our guide to tadalafil side effects.

How is the dose set through PrescribedRX?

ED treatments offered through PrescribedRX are listed on the sexual health treatments page, with prices on the pricing page. A prescription is issued only if a licensed provider determines treatment is appropriate, and your provider sets the dose. Background on ED is in our erectile dysfunction guide and erectile dysfunction by age.

Frequently asked questions

Can you take two 20 mg tadalafil doses in one day?

The Cialis prescribing information lists 20 mg as the highest as-needed dose for ED and says “the maximum recommended dosing frequency is once per day in most patients” (Cialis 2.1). Of the documents cited here, the only one listing a 40 mg daily dose is Adcirca’s, for pulmonary arterial hypertension (Adcirca prescribing information).

What is the difference between 5 mg daily and 20 mg as needed?

The prescribing information lists them as two separate ways to use tadalafil for ED. Once-daily use starts at 2.5 mg, may go up to 5 mg, and is taken at about the same time each day regardless of sexual activity. As-needed use starts at 10 mg before expected sexual activity and may go up to 20 mg (Cialis 2.1; Cialis 2.2).

Does food change the tadalafil dose?

The prescribing information says Cialis may be taken without regard to food (Cialis 2.5). It does say heavy drinking, 5 units of alcohol or more, can raise the chance of dizziness and a drop in standing blood pressure (Cialis 5.9).

Sources

1. CIALIS (tadalafil) tablets prescribing information and patient information, rev. 3/2026. DailyMed, National Library of Medicine. dailymed.nlm.nih.gov. Accessed Oct 2026.
2. ADCIRCA (tadalafil) tablets prescribing information. DailyMed, National Library of Medicine. dailymed.nlm.nih.gov. Accessed Oct 2026.
3. Erectile Dysfunction: AUA Guideline (2018). American Urological Association. auanet.org. Accessed Oct 2026.
4. Tadalafil. MedlinePlus, National Library of Medicine. medlineplus.gov. Accessed Oct 2026.
5. VIAGRA (sildenafil) prescribing information, rev. 11/2023. DailyMed, National Library of Medicine. dailymed.nlm.nih.gov. Accessed Oct 2026.

This article is for general information. It is not medical advice and it is not a recommendation for any particular treatment. Whether a treatment is appropriate for you is a decision for a licensed clinician who has reviewed your health history and current medications.