TADALCA

What it is

TADALCA is tadalafil, available in 2.5 mg, 5 mg, 10 mg or 20 mg tablets. The tablets are yellow or light yellow to yellow film coated, oval shaped, biconvex tablets for oral administration. Tadalafil is a reversible inhibitor of cyclic guanosine monophosphate (cGMP)–specific phosphodiesterase type 5 (PDE5) in the smooth muscle of the corpus cavernosum, the prostate, the bladder and their vascular supply.

Approved indications

— Erectile dysfunction in adult males. — Moderate to severe lower urinary tract symptoms associated with benign prostatic hyperplasia in adult males.

Dosing overview

For erectile dysfunction on-demand dosing, the recommended dose is either 10 mg or 20 mg, taken prior to anticipated sexual activity, with a maximum recommended dose of 20 mg. The maximum recommended dosing frequency is once per day. Tadalafil has been proven effective up to 36 hours after dosing and, in some patients, as early as 16 minutes after dosing. For frequent use (at least twice weekly), the recommended dose is 5 mg taken once a day at approximately the same time of day, and the dose must not exceed 5 mg daily. The dose may be decreased to 2.5 mg once a day based on individual tolerability. For lower urinary tract symptoms associated with benign prostatic hyperplasia, the recommended dose is 5 mg, taken at approximately the same time every day.

Key safety warnings

Nitrates and tadalafil must not be used concomitantly, and co-administration of tadalafil with nitric oxide donors, organic nitrates or organic nitrites in any form either regularly or intermittently is contraindicated. In a patient prescribed tadalafil where nitrate administration is deemed medically necessary in a life-threatening situation, at least 48 hours in most patients and 4–5 days in the elderly should have elapsed after the last dose of tadalafil before nitrate administration is considered, and nitrates should only be administered under close medical supervision with appropriate haemodynamic monitoring. Physicians should advise patients to stop taking tadalafil and seek prompt medical attention in the event of sudden decrease or loss of hearing, which may be accompanied by tinnitus. Visual defects including central serous chorioretinopathy have been reported in connection with the intake of tadalafil, with most cases resolving spontaneously after stopping tadalafil. Non-arteritic anterior ischaemic optic neuropathy, a cause of decreased vision including permanent loss of vision, has been reported rarely postmarketing in temporal association with the use of tadalafil. Priapism has been reported with tadalafil, and patients who experience erections lasting 4 hours or more should be instructed to seek immediate medical assistance. Caution should be exercised when prescribing tadalafil to patients who are taking alpha-blockers, such as doxazosin, as simultaneous administration may lead to symptomatic hypotension in some patients.

Contraindications

Tadalafil is contraindicated in men for whom sexual intercourse is inadvisable due to unstable cardiovascular disease, such as patients with unstable angina and severe congestive heart failure. Tadalafil is contraindicated in patients who have loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy, regardless of whether this episode was in connection or not with previous PDE5 inhibitor exposure. Tadalafil is contraindicated in patients with a myocardial infarction within the last 90 days, unstable angina or angina occurring during sexual intercourse, New York Heart Association Class 2 or greater heart failure in the last 6 months, uncontrolled arrhythmias or hypotension (less than 90/50 mm Hg) or uncontrolled hypertension, and patients with a stroke within the last 6 months. Tadalafil should not be used in patients with a known hypersensitivity to tadalafil or to any ingredient of the tablet. The combination of tadalafil and guanylate cyclase stimulators, such as riociguat, is contraindicated because it may lead to symptomatic hypotension.

PBS listing

The 20 mg tablet strength is listed on the PBS under 4 items with authority required restriction, at an ex-manufacturer price of A$475.54.

Regulatory history

TADALCA (20 mg tablet) was first registered on the ARTG on 15 January 2018 under licence category RE, sponsored by Pharmacor.