Tadalafil dosage, forms, and strengths

Tadalafil is a generic prescription drug that is used to treat pulmonary arterial hypertension, erectile dysfunction (ED), or the lower urinary tract symptoms of prostate enlargement (benign prostatic hyperplasia or BPH). Tadalafil is only available as a tablet and is taken by mouth once a day with or without food. Although sold as a generic drug, tadalafil is also available as two well-known brand-name drugs—Cialis and Adcirca. Cialis is sold in tablet strengths appropriate for erectile dysfunction and enlarged prostate. Adcirca comes in strengths suitable to treat pulmonary hypertension.  

Tadalafil belongs to a family of drugs called PDE5 inhibitors, or “phosphodiesterase type 5 inhibitors.” These drugs relax the smooth muscles in blood vessels, particularly arteries, causing them to widen. This lowers blood pressure in pulmonary arteries, alleviating pulmonary hypertension, and increases and prolongs blood flow to the penis, helping to improve men’s sexual function. PDE5 inhibitors also relax muscles in the bladder and lower urinary tract, helping to relieve urinary symptoms in men with prostate enlargement. 

RELATED: Learn more about tadalafil | Get tadalafil discounts

Tadalafil dosage, forms, and strengths

Tadalafil is taken as a tablet in four different dose strengths.

• Tablet: 2.5 milligrams (mg), 5 mg, 10 mg, and 20 mg

Tadalafil dosage for adults

Tadalafil is taken once a day for pulmonary hypertension or BPH. It can be taken daily or as needed for erectile dysfunction.

• Standard dosage for adults: 2.5–5 mg (BPH or ED) or 40 mg (pulmonary arterial hypertension) once per day or 5–20 mg as needed (ED)

• Maximum dosage for adults: No more than 20 mg per day (BPH or ED) or 40 mg per day (pulmonary hypertension)

Tadalafil dosage for children

Tadalafil has not been approved by the FDA for use in people younger than 18 years of age.

As-needed dosage for erectile dysfunction

As a treatment of erectile dysfunction, tadalafil can be taken as needed to improve sexual function. Prescriptions will typically come in 5 mg, 10 mg, and 20 mg strengths. The starting dose is typically started at 10 mg, but this dose may be reduced to 5 mg or increased to as much as 20 mg depending on the effectiveness and tolerability of the starting dose.

• Adults (18 years and older): 5–20 mg taken before anticipated sexual activity

• Renally impaired patients (kidney disease)—dose amount adjustment: 

  • Creatinine clearance of 30–50 milliliters (ml)/min: 5-10 mg once per day to a maximum of 10 mg every 48 hours

  • Creatinine clearance less than 30 ml/min: 5 mg every 72 hours

  • Hemodialysis: 5 mg every 72 hours, no supplement after dialysis

  • Peritoneal dialysis: Not defined

• Hepatically impaired patients (liver disease)—dose amount adjustment: 

  • Mild to moderate hepatic impairment: Use with caution; 5–10 mg to a maximum of 10 mg every 24 hours

• Severe hepatic impairment: Not recommended

Daily dosage for erectile dysfunction

Alternatively, tadalafil can be taken daily at a lower dose to treat erectile dysfunction. Sexual activity can be engaged in at any time between doses.

• Adults (18 years and older): 2.5–5 mg taken once per day

• Renally impaired patients (kidney disease): 

  • Creatinine clearance less than 30 ml/min: Not recommended

  • Hemodialysis: Not recommended

  • Peritonealdialysis: Not defined

• Hepatically impaired patients (liver disease):

  • Mild to moderate hepatic impairment: Use with caution

  • Severe hepatic impairment: Not recommended

 Dosage for symptoms of benign prostatic hyperplasia (BPH)

Tadalafil is prescribed as a daily dose to alleviate lower urinary tract symptoms due to benign prostatic hyperplasia, often in combination with other drugs such as finasteride. Erectile dysfunction may also be experienced by men with enlarged prostates, so a daily tadalafil dose can treat both conditions.

• Adults (18 years and older): 5 mg taken once per day

• Renally impaired patients (kidney disease)—dose amount adjustment:

  • Creatinine clearance of 30–50 ml/min: 2.5–5 mg once per day

  • Creatinine clearance less than 30 ml/min: Not recommended

  • Hemodialysis: Not recommended

  • Peritonealdialysis: Not defined

• Hepatically impaired patients (liver disease):

  • Mild to moderate hepatic impairment: Use with caution

  • Severe hepatic impairment: Not recommended

Dosage for pulmonary arterial hypertension

Tadalafil is used to improve exercise ability in people with pulmonary arterial hypertension. The dose, however, is higher than it is for other indications: 40 mg once per day. People with pulmonary hypertension, then, will receive prescriptions for 20 mg tadalafil tablets specifically indicated for pulmonary hypertension.

• Adults (18 years and older): 40 mg taken once per day

• Renally impaired patients (kidney disease)—dose amount adjustment:

  • Creatinine clearance of 30–50 ml/min: 20–40 mg once per day

  • Creatinine clearance less than 30 ml/min: Avoid use

  • Hemodialysis: Avoid use

  • Peritoneal dialysis: Not defined

• Hepatically impaired patients (liver disease):

  • Mild to moderate hepatic impairment: Use with caution; consider starting dose 20 mg once per day

  • Severe hepatic impairment: Avoid use 

Tadalafil dosage for pets

The FDA has not approved tadalafil for use in animals. Some veterinarians, however, may prescribe tadalafil to dogs for pulmonary hypertension. The research, however, is limited. For this reason, no standard veterinary dosages have been defined, so individual practitioners may prescribe different doses based on their experience. Do not, however, give tadalafil or any other human prescription drug to a pet except under the direction of a veterinarian. The dose may be wrong, and one or more of the inactive ingredients may be harmful to the animal. 

How to take tadalafil

Tadalafil is taken by mouth as a tablet with or without food. It will be prescribed either as a once-daily dose or on an as-needed basis.

• Only take tadalafil with a prescription and under the care of a healthcare provider. Take the medicine as directed by a healthcare provider.

• Swallow the tablet whole. Do not crush or chew it.

• Do not take more than one dose per day or split the dose into two daily doses.

• For daily use, the tadalafil dose should be taken at the same time each day.

• Carefully read and follow the patient information brochure that comes with the prescription.

• For erectile dysfunction, sexual activity can be initiated any time from 30 minutes to 36 hours after taking tadalafil.

• For erectile dysfunction, sexual stimulation is required for an erection.

• Drinking alcohol within 36 hours of a tadalafil dose may lower blood pressure, so alcohol use is best avoided. 

• If too much tadalafil is taken, seek immediate medical advice. 

• Always check the expiration date. If the expiration date has passed, dispose of the medication safely and get a new prescription.

• Tadalafil should be stored at room temperature. Check the patient information brochure for the ideal temperature range.

Tadalafil dosage FAQs

How long does it take tadalafil to work?

When taken orally, tadalafil quickly enters the bloodstream and hits maximum concentration in the blood within 30 minutes to six hours. Its bioavailability and immediate effectiveness are not affected by food.

How long does tadalafil stay in your system?

Tadalafil lasts for a long-time in the body. With a half-life of 17.5 hours for healthy people and up to 35 hours for people with pulmonary hypertension, a single dose of tadalafil can take four days or more to clear out of the body. This is why tadalafil is often nicknamed “the weekend pill”: its effects when treating erectile dysfunction can persist for up to 36 hours.

What happens if I miss a dose of tadalafil?

A missed dose can be taken when remembered, but do not take more than one dose in a single day. People with pulmonary hypertension will usually have to take two 20 mg pills each day. Do not divide these two pills into two separate doses. Take them at the same time. Never take extra doses of tadalafil to make up for a missed dose.

How do I stop taking tadalafil?

Tadalafil does not create physical dependency, though men using tadalafil in excess without a prescription may feel psychologically dependent on the medication. Tadalafil can be discontinued without withdrawal symptoms or any need for tapered dosing. However, patients with pulmonary hypertension should check with their healthcare provider before stopping tadalafil.

Some circumstances may require people to immediately stop taking tadalafil, especially any sudden loss of vision in one or both eyes or sudden hearing loss, both of which will require emergency medical treatment. Any allergic reaction to the drug such as hives, rash, trouble breathing, or swelling around the face or throat is a signal the medicine should be stopped until the cause of the reaction can be determined. 

What is the maximum dosage for tadalafil?

Men taking tadalafil for erectile dysfunction should not take more than 20 mg per day. The recommended daily dose for pulmonary hypertension is 40 mg per day and should not be exceeded. Excessive doses significantly raise the risk of dangerously low blood pressure, prolonged and painful erections, cardiovascular changes, and vision or hearing loss.

What interacts with tadalafil?

Food doesn’t affect the body’s ability to absorb tadalafil. However, avoid grapefruit or grapefruit juice. Grapefruit has substances that hamper the ability of the body to break down tadalafil. 

Tadalafil is metabolized by the enzyme CYP3A4. Numerous other medications can increase or decrease the activity of this enzyme, which can lead to heightened or reduced activity of tadalafil. Have your healthcare provider review your medication list to determine if any of these medication interaction concerns pertain to you. Certain blood pressure medications, such as alpha blockers, and erectile dysfunction drugs similar to tadalafil like sildenafil, available as Viagra or Revatio, and vardenafil, sold under the brand name Levitra, should also be avoided due to the potential for reduced blood pressure if taken together with tadalafil. Anyone taking nitrates, which are used for chest pain, heart conditions, and high pressure, should typically avoid tadalafil. Talk to your healthcare provider about all possible interactions and if tadalafil is right for you.

Resources

• Adcirca prescribing information

• Cialis

• Cialis prescribing information

• Clinical efficacy of tadalafil compared to sildenafil treatment of moderate to severe pulmonary hypertension: a pilot study

• Tadalafil monograph

• Tadalafil

• Tadalafil compound summary