A 60-year-old man was admitted to our hospital. He had mild tremor in his four extremities when supine or sitting, which was markedly exacerbated when standing. We diagnosed him with Machado-Joseph disease according to the genetic test. His tremor improved with clonazepam, trihexyphenidyl, and a rotigotine patch.

Trihexyphenidyl works as an anticholinergic and is used for the treatment of tremors, spasms, stiffness, and weak muscle control seen in patients with Parkinson disease.[1] It can also be used for the prevention or treatment of similar muscular conditions which are caused by certain central nervous system (CNS) drugs such as fluphenazine, haloperidol, chlorpromazine. Although it has been pertinent in clinical trials investigating the treatment of Parkinson disease since 1949, it was approved for the management of all types of parkinsonism (idiopathic, postencephalitic, and arteriosclerotic) in June 2003 by the FDA.[2] Trihexyphenidyl is often used as an adjuvant therapy when treating the above-mentioned forms of parkinsonism with levodopa.[2]

Acute antipsychotic-induced movement disorders (AIMD) are clinically relevant since they are frequently associated with high subjective distress, and since over the long-term they can negatively impact treatment adherence of patients with schizophrenic psychoses. This review article summarizes the relevant studies on the prevalence, risk factors, prevention and treatment options and instruments for early prediction of acute AIMD in schizophrenic psychoses. The current evidence and treatment recommendations are divided into three main areas: acute dystonia, akathisia, and parkinsonism. For the treatment of acute dystonia trihexyphenidyl and biperiden have shown their efficacy. Considering pharmacological treatment of akathisia, there is some preliminary evidence for medication with lipophilic beta-receptor blockers (propranolol and pindolol), clonidine, benzodiazepines, mianserin, mirtazapine und trazodone. The treatment options for drug-induced parkinsonism include reduction or switching from one antipsychotic to another with a lower affinity for dopamine D2 receptors, amantadine or in the regular administration of anticholinergic drugs. In conclusion, acute AIMD is easily to recognize but is not always effectively and durably treated. Early recognition and treatment of acute AIMD could be associated with improved treatment outcomes.

Trihexyphenidyl is an anticholinergic medication that is routinely used for the management of extrapyramidal symptoms in patients who receive antipsychotic medications. Trihexyphenidyl has been reported to be abused by some patients, who start to take it in increasing doses and tend to report a sensation of relaxation or pleasure with this medication. Hence, whether trihexyphenidyl should be considered a psychoactive substance and whether nonprescription misuse of this medication should be considered under the purview of substance use disorders need further clarity. We present here two cases of trihexyphenidyl misuse which developed in the context of persistent delusional disorders and highlight the challenges in diagnosis in such a situation.

In this study, a chiral CE method was developed based on the partial filling technique with two chiral plugs for the simultaneous enantioseparation of some racemic drugs, including baclofen, carvedilol, cetirizine, chlorpheniramine, citalopram, fluoxetine, hydroxyzine, propranolol, tramadol, trihexyphenidyl. This method of capillary filling involves the application of two adjacent chiral plugs containing the same BGE, but with different chiral selectors in the plugs for the enantioseparation of a mixture of drugs which cannot be separated with single or mixed chiral selectors. By using this method, each plug can separate the enantiomers independently (same as a single chiral selector modified CE) and the possible interactions between the chiral selectors would be inhibited. The best results were obtained using a fused silica capillary (60cm×50μm id (50cm effective length)) with phosphate buffer (100mM, pH 3.0) containing 10mM hydroxypropyl-α/β-cyclodextrin and 10% (w/v) maltodextrin and detected by UV at 214nm. The influence of the length and order of the chiral plugs on the enantioresolution was also studied and optimized. The proposed method was compared with a mixed chiral selector-CE system with a combination of hydroxypropyl-α-cyclodextrin/hydroxypropyl-β-cyclodextrin and maltodextrin in the BGE. According to the results, the modified partial filling method is a simple and efficient method for the simultaneous chiral separation and offers appropriate migration times and resolutions compared to the results obtained from mixed chiral selector CE.

Limited information indicates that maternal doses of trihexyphenidyl up to 4 mg daily together with haloperidol did not produce any adverse effects in breastfed infants. Long-term use of trihexyphenidyl might reduce milk production or milk letdown, but a single dose is not likely to interfere with breastfeeding. During long-term use, observe for signs of decreased lactation (e.g., insatiety, poor weight gain).

No information is available on the use of flavoxate during breastfeeding. Long-term use of trihexyphenidyl might reduce milk production or milk letdown, but a single dose is not likely to interfere with breastfeeding. During long-term use, observe for signs of decreased lactation (e.g., insatiety, poor weight gain).

We previously showed that nicotine evoked kinetic tremor by activating the inferior olive, which is implicated in the pathogenesis of essential tremor, via α7 nicotinic acetylcholine receptors. Here, we evaluated the effects of various anti-tremor and anti-epileptic agents on nicotine-induced tremor in mice to clarify the pharmacological characteristics of nicotine tremor. Drugs effective for essential tremor, propranolol, diazepam and phenobarbital, all significantly inhibited kinetic tremor induced by an intraperitoneal (i.p.) injection of nicotine (1 mg/kg). In contrast, none of the medications for Parkinson's disease, l-DOPA, bromocriptine or trihexyphenidyl, affected the nicotine tremor. Among the anti-epileptic agents examined, valproate, carbamazepine and ethosuximide, significantly inhibited nicotine-induced tremor. In addition, a selective T-type Ca2+ channel blocker, TTA-A2, also suppressed the nicotine tremor. However, neither gabapentin, topiramate, zonisamide nor levetiracetam significantly affected nicotine-induced tremor. The present results show that nicotine-induced tremor resembles essential tremor not only on the neural basis, but also in terms of the pharmacological responses to anti-tremor agents, implying that nicotine-induced tremor can serve as a model for essential tremor. In addition, it is suggested that anti-epileptic agents, which have stimulant actions on the GABAergic system or blocking actions on voltage-gated Na+ channels and T-type Ca2+ channels, can alleviate essential tremor.