Hi everyone!
Hope all is well and keeping safe at this current stage.
Quick question, anyone heard of the medicine above and have you used it?
Thanks guys x
Hi @Sasha and welcome back to the forum 
Trihexyphenidyl (also known as benzhexol) is a type of drug called an anticholinergic. Anticholinergics are not commonly used to treat Parkinson’s but they can be used to help a noticeable tremor.
There’s lots more information about anticholinergics on our website that you might find useful.
You might also find it helpful to chat to the Parkinson’s nurses on our Helpline who can answer general questions about medications.
Warm regards,
Katie
Forum Moderation Team
I was given this drug in April 2003. I wasn’t told that it was used as an “antidote” to the side effects of a previous drug. No-one told me a thing about drug-induced movement disorders. As I have posted earlier, I have never felt so bad in my life. The only side effects I remember my gp telling me about were dry mouth and constipation.
If you look the drug up online you will get more information than the patient information leaflet, especially the section “for professionals” which may give you some of the proper medical terms.
Anticholinergic drugs …the only effective medical therapy for Parkinson’s disease for almopst 100 years… Charcot’s pupil ORDENSTEIN (1867) first discovered their antiparkinsonian effects fortuitously when he administered tinctures of deadly nightshade (Atropa belladonna) and henbane (Hyoscyamus niger) to patients in hopes of drying their mouths in order to control the excessive salivation and drooling. ( Drugs for the Treatment of Parkinson’s Disease pp 307-323 Springer-Verlag 1989)
TRIHEXYPHENIDYL hydrochloride was introduced as a synthetic drug for the treatment of Parkinson’s disease in Aug, 1949. Approved by FDA (USA) June 25th, 2003 all types of parkinsonism. Licensed.by MHRA (UK) 15th Nov.2006.
Medical Editor: John P. Cunha, DO, FACOEP Last reviewed on RxList 9/7/2018
Artane (trihexyphenidyl) is an antispasmodic drug used to treat the stiffness, tremors, spasms, and poor muscle control of Parkinson’s disease. Artane is also used to treat and prevent the same muscular conditions when they are caused by certain drugs.[ ie.Drug-Induced Parkinsonism/Extrapyramidal symptoms].
Side effects of Artane include: dry mouth & constipation…
nervousness, agitation, anxiety, restlessness, [ie.akathisia]
rapid or jerky repetitive involuntary movement, hyperactivity, chorea/choreiform movements [ie.dyskinesia]
cognitive dysfunctions, including hallucinations, confusion and memory impairment, psychosis,
MENTAL SYMPTOMS IN PARKINSONISM FOLLOWING BENZHEXOL HYDROCHLORIDE THERAPY BY H. B. PORTEOUS, AND D. N. ROSS. BMJ 138 JULY 21, 1956
Case 1: In August, as he did not seem to be improving, he was placed on gradually increasing doses of benzhexol hydrochloride to 20 mg. daily, when he became mentally confused and had mild delusions. On October 1 he made an abortive attempt at suicide. After a period in an observation ward he improved mentally and he returned to this unit. He had ceased to take the drug. … However, his tremors increased and so did his rigidity, to such an extent that it was thought advisable to start with small doses of benzhexol hydrochloride, and he was put on 7.5 mg. daily. Within a few days he again became mildly confused and his delusions returned, and a further attempt at suicide caused him to be removed to a mental hospital.
Drug treatment of Parkinson’s disease Niall Quinn, BMJ 1995 Mar 4; 310(6979): ;575-579
The anticholinergic drugs most commonly used to treat Parkinson’s disease in the United Kingdom are benzhexol (usual dose about 2 mg three times a day) and orphenadrine (50-100 mg three times a day). These drugs have a mild antiparkinsonian effect, and are said to be more effective for tremor than for the other features of parkinsonism. They may worsen choreiform dyskinesia and lessen some dystonic side effects of levodopa. The most serious side effects, however, are neuropsychiatric.
Parkinson’s disease and other movement disorders M.Edwards, N.Quinn, K.Bhatia OUP 2008
p.222 Drug-induced chorea The two most important causes of drug-induced chorea…levodopa-induced dyskinesia (chorea) in Parkinson’s disease & tardive dyskinesia (chorea) due to chronic dopamine receptor blocking drug exposure.
An important pitfall to be aware of is that anticholinergic drugs such as trihexyphenidyl can cause chorea. This can create diagnostic confusion when anticholinergics are given to treat dystonia. If such patients then develop chorea, it can be difficult to determine whether the chorea is caused by the anticholinergic drug, or is part of the underlying movement disorder.
https://davidhealy.org/dr-munchausen-pharmacophile/
Dr Munchausen: Pharmacophile David Healy September, 10, 2014
The prescription of a medicine now assumes that a patient should understand the condition for which the prescription is given, the nature of any treatment, its duration, its chances of success and the risks of side effects. Patients should be free to ask for any information they want from the prescriber, who will respond genuinely… a paternalistic approach to patients may involve an insidious loss of autonomy that may be counter-therapeutic and ethically dubious.