ARTANE

What it is

Artane is supplied in two tablet strengths containing 2 mg and 5 mg trihexyphenidyl hydrochloride. The tablets are white, round, flat-faced, bevelled edge tablets with a break bar on one side and plain on the other.

Approved indications

— As an adjunct in the therapy of all forms of Parkinsonism (postencephalitis, arteriosclerotic and idiopathic). — Prevention or control of extrapyramidal disorders due to central nervous system drugs such as phenothiazines.

Dosing overview

Dosage should be individualised, and the initial dose should be low and then increased gradually, especially in patients over 60.

Key safety warnings

Trihexyphenidyl can induce cycloplegia and mydriasis, resulting in increased intraocular pressure. Patients to be treated with Artane should have a gonioscopic evaluation and close monitoring of intraocular pressures at regular intervals. If blurring of vision occurs during therapy, the possibility of narrow angle glaucoma should be considered. Blindness has been reported due to aggravation of narrow angle glaucoma. Artane should be administered with caution in the presence of fever, high environmental temperature, and/or during physical exercise, especially when given concomitantly with other atropine-like drugs to the chronically ill, alcoholics, those with central nervous system disease, or those who do manual labour in a hot environment. Severe anhidrosis and fatal hyperthermia have occurred with the use of anticholinergics under the conditions described above. A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with dose reduction or discontinuation of Artane. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). Artane has anticholinergic properties; as a result, existing hypertension may be aggravated and tachycardia may occur. Patients at risk (arrhythmia, heart failure, coronary heart disease, mitral stenosis) should be monitored carefully over a prolonged period. Artane should be used with caution in patients with cardiac disease such as ischaemic heart disease, or with atherosclerosis and hypertension because of its positive chronotropic effect that could cause tachycardia and/or coronary ischaemia. Artane has been shown to cause some cognitive dysfunctions in the elderly, including confusion, delusions and hallucinations and memory impairment.

Contraindications

Artane is contraindicated in patients with hypersensitivity to trihexyphenidyl or any other ingredients of the preparation, and narrow angle glaucoma.

PBS listing

The 5 mg tablet is listed on the PBS with one item, unrestricted restriction, at an ex-manufacturer price of A$8.29. The 2 mg tablet is listed on the PBS with one item, unrestricted restriction, at an ex-manufacturer price of A$4.80.

Regulatory history

Artane 5 mg tablets were first listed on the ARTG on 9 September 1991, and Artane 2 mg tablets were first listed on the ARTG on 9 September 1991. The medicine was first approved on 8 April 2004.