Anticholinergic agents can induce oromandibular dyskinesia

Impact of anticholinergic drugs withdrawal on motor function in patients with Parkinson's disease

OBJECTIVES

Physicians have prescribed anticholinergic agents as monotherapy or adjuvant therapy in patients with Parkinson's disease for decades. However, these medications can cause many adverse effects including gait freezing and falling. Herein we assessed the effects of anticholinergic medications on motor function, freezing of gait and falling in a group of patients with PD.

PATIENTS AND METHODS

This prospective study evaluated the effect of gradual discontinuation of anticholinergics on motor function in 131 outpatients with Parkinson's disease. We assessed patients' motor function at baseline six and twelve months later using the UPDRS-III. We also evaluated freezing of gait and falling in patients using UPDRS-II part 14 and 13 respectively. The anticholinergics were tapered and gradually discontinued and additional levodopa doses were added as patients needed.

RESULTS

131patients successfully discontinued their anticholinergic medications. Stopping anticholinergics significantly improved the motor symptoms in PD patients as reflected in the change between the mean (±SD) UPDRS-III score of 36.85(±11.5) at the baseline to 32.51(±11.4) and 31.43 (±11.3) after six and twelve months (P < 0.001). The mean (±SD) scores of freezing of gait (FOG)significantly changed from 1.34(±1) to 1.17(±1) and 0.6(±0.7) and for falling down from 0.62(±0.8) to 0.5 (±0.8) and 0.29(±0.5) respectively (p-value of <0.001).

CONCLUSION

Our finding demonstrated an improvement in motor function and FOG and falling incidences in PD patients, after discontinuation of anticholinergic drugs. As motor complications adversely affect the quality of life in PD patients, clinicians must be careful with the unnecessary use of anticholinergic drugs in their treatment strategies.

Treatment of Tardive Dyskinesia: A General Overview with Focus on the Vesicular Monoamine Transporter 2 Inhibitors

Tardive dyskinesia (TD) encompasses the spectrum of iatrogenic hyperkinetic movement disorders following exposure to dopamine receptor-blocking agents (DRBAs). Despite the advent of atypical or second- and third-generation antipsychotics with a presumably lower risk of complications, TD remains a persistent and challenging problem. Prevention is the first step in mitigating the risk of TD, but early recognition, gradual withdrawal of offending medications, and appropriate treatment are also critical. As TD is often a persistent and troublesome disorder, specific antidyskinetic therapies are often needed for symptomatic relief. The vesicular monoamine transporter 2 (VMAT2) inhibitors, which include tetrabenazine, deutetrabenazine, and valbenazine, are considered the treatment of choice for most patients with TD. Deutetrabenazine-a deuterated version of tetrabenazine-and valbenazine, the purified parent product of one of the main tetrabenazine metabolites, are novel VMAT2 inhibitors and the only drugs to receive approval from the US FDA for the treatment of TD. VMAT2 inhibitors deplete presynaptic dopamine and reduce involuntary movements in many hyperkinetic movement disorders, particularly TD, Huntington disease, and Tourette syndrome. The active metabolites of the VMAT2 inhibitors have high affinity for VMAT2 and minimal off-target binding. Compared with tetrabenazine, deutetrabenazine and valbenazine have pharmacokinetic advantages that translate into less frequent dosing and better tolerability. However, no head-to-head studies have compared the various VMAT2 inhibitors. One of the major advantages of VMAT2 inhibitors over DRBAs, which are still being used by some clinicians in the treatment of some hyperkinetic disorders, including TD, is that they are not associated with the development of TD. We also briefly discuss other treatment options for TD, including amantadine, clonazepam, Gingko biloba, zolpidem, botulinum toxin, and deep brain stimulation. Treatment of TD and other drug-induced movement disorders must be individualized and based on the severity, phenomenology, potential side effects, and other factors discussed in this review.