CYROTONE-100

What it is

CYROTONE-100 contains the active ingredient cyproterone acetate. It is an antiandrogen, classified under ATC code G03HA01. Cyproterone acetate inhibits competitively the effect of androgens at androgen-dependent target organs, shielding the prostate from the effect of androgens originating from the gonads and the adrenal cortex.

Approved indications

— Inoperable prostatic carcinoma to suppress flare with initial luteinising hormone releasing hormone (LHRH) analogue therapy — Long-term palliative treatment of inoperable prostatic carcinoma where LHRH analogues or surgery are ineffective, not tolerated, contraindicated or where oral therapy is preferred — Treatment of hot flushes in patients treated with LHRH analogues or who have had orchidectomy

Dosing overview

The maximum daily dose is 300 mg.

Key safety warnings

Direct hepatic toxicity, including jaundice, hepatitis and hepatic failure, has been observed in patients treated with CYROTONE-100, with cases of fatal outcome reported at dosages of 100 mg and above. Toxicity is dose-related and usually develops several months after treatment has begun, and liver function tests should be performed pre-treatment, at regular intervals during treatment and whenever symptoms or signs suggestive of hepatotoxicity occur. Meningiomas have been reported in association with long-term use (years) of CYROTONE-100 at doses of 25 mg per day and above. If a patient is diagnosed with meningioma during treatment, CYROTONE-100 must be stopped. Thromboembolic events have been reported in patients using CYROTONE-100, although a causal relationship has not been established; patients with previous arterial or venous thrombotic or thromboembolic events or advanced malignancies are at increased risk of further thromboembolic events. Long-term androgen deprivation with CYROTONE-100 may lead to osteoporosis in male patients. During treatment, hepatic function, adrenocortical function and red blood cell count should be checked regularly.

Contraindications

CYROTONE-100 is contraindicated in patients with liver diseases, Dubin-Johnson syndrome, Rotor syndrome, previous or existing liver tumours (only if not due to metastases from prostate carcinoma), presence or history of meningioma, wasting diseases (except carcinoma of the prostate), severe chronic depression, previous or existing thromboembolic processes, severe diabetes with vascular changes, and sickle-cell anaemia. CYROTONE-100 is also contraindicated in patients with hypersensitivity to any of its components.

Regulatory history

CYROTONE-100 was first included in the Australian Register of Therapeutic Goods on 23 May 2012. Two ARTG registrations are maintained for the brand: ARTG 184197 for the blister pack formulation and ARTG 184199 for the bottle formulation, both registered as 100 mg tablets and first listed on 23 May 2012.