What is Artane (Trihexyphenidyl)?
Artane (trihexyphenidyl) is an anticholinergic medication indicated as adjunctive therapy for all forms of parkinsonism (postencephalitic, arteriosclerotic, and idiopathic) and for controlling extrapyramidal side effects caused by antipsychotic medications such as phenothiazines, thioxanthenes, and butyrophenones. 1
Primary Indications
Parkinsonism Treatment
- Trihexyphenidyl serves as adjuvant therapy when treating parkinsonism with levodopa, helping to manage motor symptoms associated with the disease 1
- In previously untreated Parkinson's disease patients, trihexyphenidyl at 6 mg daily for 5-11 weeks produces improvements in motor symptoms 2
Extrapyramidal Symptom Control
- The medication is specifically indicated for controlling drug-induced extrapyramidal disorders caused by central nervous system drugs, particularly antipsychotics including dibenzoxazepines, phenothiazines, thioxanthenes, and butyrophenones 1
- Trihexyphenidyl demonstrates equal effectiveness to amantadine in treating neuroleptic-induced parkinsonism, though amantadine produces fewer side effects 3
Mechanism of Action
- Trihexyphenidyl is a synthetic anticholinergic agent that works by blocking muscarinic cholinergic receptors 4
- The drug inhibits the cortical cholinergic system and significantly decreases regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of oxygen (rCMRO2) by approximately 15% in the striatum and 10% in cortical areas 2
Critical Prescribing Considerations
Contraindications and Warnings
- Trihexyphenidyl should be avoided in patients with extrapyramidal symptoms caused by typical antipsychotics, as it may increase the risk of tardive dyskinesia, according to the American Family Physician 5
- High doses may precipitate anticholinergic toxic psychosis and interfere with antipsychotic therapeutic effects by impeding their absorption 6
Abuse Potential
- Trihexyphenidyl has documented mood-elevating, euphorigenic, and socially-stimulating effects that create abuse potential 6, 7
- Patients may abuse the medication at doses up to 200 mg per day to achieve euphoric effects, with the most common reasons for misuse being anxiolytic effects (46%), stimulation (26%), and sedation (10%) 6, 7
- Clinicians should exercise heightened vigilance when prescribing to patients with substance abuse history, as the drug is readily available in pharmacies without adequate surveillance 6, 7
Cognitive and Metabolic Effects
- Despite causing 10-15% reductions in cerebral blood flow and oxygen metabolism across cortical areas, trihexyphenidyl does not produce significant cognitive impairment in untreated Parkinson's disease patients at therapeutic doses 2
Common Pitfalls to Avoid
- Do not prescribe trihexyphenidyl as monotherapy for antipsychotic-induced extrapyramidal symptoms without considering the increased tardive dyskinesia risk 5
- Avoid prescribing to patients with known substance abuse histories without implementing strict monitoring protocols, as coaddiction occurs in 61% of cases, particularly with benzodiazepines, cannabis, and buprenorphine 7
- Do not assume the medication lacks abuse potential simply because it is an anticholinergic agent—patients may feign extrapyramidal symptoms to obtain additional doses 6