Mirtazapine in Parkinsonian tremor

Mirtazapine, an FDA-approved drug for major depression, has been previously reported to reduce tremor due to Parkinson's disease (PD) and essential tremor (ET) in a case report of five patients providing subjective accounts [ [1] Pact V. Giduz T. Mirtazapine treats resting tremor, essential tremor, and levodopa-induced dyskinesias. Neurology. 1999; 53: 1154 Crossref PubMed Scopus (82) Google Scholar ]. It acts as a central presynaptic alpha-2 receptor antagonist, enhancing norepinephrine and serotonin neurotransmission via the 5HT1 receptor, while selectively blocking postsynaptic 5HT2 and 5HT3 receptors [ [2] de Boer T. The effects of mirtazapine on central noradrenergic and serotonergic neurotransmission. Int Clin Psychopharmacol. 1995; 10: 19-23 Crossref PubMed Scopus (178) Google Scholar ]. It also has antihistaminic properties. It is generally well tolerated, and has been used in millions of patients to treat depression [ [2] de Boer T. The effects of mirtazapine on central noradrenergic and serotonergic neurotransmission. Int Clin Psychopharmacol. 1995; 10: 19-23 Crossref PubMed Scopus (178) Google Scholar ]. Medications with effects on the adrenergic system have reported benefits in early studies in the PD population [ [3] Brefel-Courbon C. Thalamas C. Saint-Paul H.P. et al. Alpha-2 adrenoceptor antagonists: a new approach to Parkinson's disease?. CNS Drugs. 1998; 10: 189-207 Crossref Scopus (37) Google Scholar ], and Parkinsonian tremor may be under the influence of serotonergic mechanisms [ 4 Jenner P. Marsden C.E.D. Neurochemical basis of parkinsonian tremor. in: Findley L.J. Capildeo R. Movement disorders: tremor. Macmillan, London1984: 305-320 Google Scholar , 5 Pinder R.M. Drug-induced tremor. in: Findley L.J. Capildeo R. Movement disorders: tremor. Macmillan, London1984: 445-462 Google Scholar ]. Serotonergic agents can also enhance inferior olivary neuronal rhythmicity in experimental animals producing tremor [ [6] Elbe R.J. Animal models of action tremor. Mov Disord. 1998; 13: 35-39 Google Scholar ].