> Western Medicines > Tadalafil


Used for: Erectile dysfunction, Pulmonary arterial hypertension, Benign Prostatic Hyperplasia (BPH)
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What is Tadalafil for?

Tadalafil belongs to a class of medications called phosphodiesterase inhibitors. Tadalafil (Cialis) is used to treat erectile dysfunction (impotence) in men by increasing blood flow to the penis during sexual stimulation, which can cause an erection. It is also used to relieve symptoms of benign prostatic hyperplasia, which include difficulty urinating, hesitancy or difficulty to start urinating, weak stream, incomplete bladder emptying, and urinary frequency and urgency in adult men.

Tadalafil is also used to treat pulmonary arterial hypertension (high blood pressure in the lungs) by dilating blood vessels in the lungs to allow blood to flow easily.

How to use it?

Tadalafil can be taken by mouth, with or without food.


Erectile dysfunction
Initially 10 mg at least 30 minutes before sexual intercourse, may increase to 20 mg depending on response. Alternatively, 5 mg once daily, taken at the same time each day, may decrease to 2.5 mg depending on response. Use no more than once every 24 hours.


Benign prostatic hyperplasia
5 mg once daily, taken at the same time each day.


Pulmonary arterial hypertension
40 mg once daily.

What are the side effects of Tadalafil?

Common side effects of Tadalafil include flushing, headache, muscle pain, nasal congestion, and gastrointestinal discomfort.

Who should not take Tadalafil?

  • People allergic to Tadalafil or any component of the formulation
  • Patients who are currently taking nitrates regularly or as emergency medication
  • Patients who recently had myocardial infarction or stroke

Pharmacist Tips:

  • This medication can make you dizzy. Avoid driving or operating machinery until you know how you respond to Tadalafil.
  • Report to your doctor immediately if you experience sudden visual or hearing loss.
  • Report to your doctor immediately and refrain from physical activities (including sexual activity) if you experience symptoms of angina, palpitations or fast heart beat.
  • If you are using Tadalafil for erectile dysfunction, seek medical assistance in case of prolonged erection (over 4 hours).
  • Avoid alcohol while taking this medication.

Common dosing schedule:
Take Tadalafil once daily. Take with or without food at the same time each day.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Tadalafil may interact with:

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Tadalafil in Hong Kong?

In Hong Kong, Tadalafil is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Tadalafil in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 2.5mg / 5mg / 10mg / 20mg (Tablets)
Drug class
Vasodilators, Antihypertensives
Sub class
Phosphodiesterase Inhibitors
Other drugs in same class
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Chinese name: