Parkinson's disease (PD) is characterized by many non-motor symptoms that occur several years before the diagnosis, in particular idiopathic REM behavior disorder (iRBD), which is associated with autonomic impairment. The purpose of this study is to investigate the effect of treatment with the selective post-synaptic a1-adrenergic blocker terazosin on 123I-MIBG myocardial uptake in a population of subjects with defined pre-motor PD risks (i.e. hyposmia and RBD) and abnormal baseline 123I-MIBG uptake, with or without 123I-Ioflupane uptake abnormality or PD motor symptoms. Scintigraphic changes will be correlated to motor and non-motor severity of PD, measured by validated clinical scales and cardiac autonomic function tests.
Based on the increased risk to develop PD, individuals with iRBD are currently considered ideal candidates for therapies that can possibly protects brain cells, due to the critical window of opportunity to intervene early before brain cell loss progresses significantly. Early changes of PD are associated with a number of symptoms including loss of smell, constipation, anxiety and depression. In addition, early heart and brain abnormalities can be visualized using specialized imaging techniques called 123I-MIBG myocardial scintigraphy (MIBG) and dopamine transporter (DAT) single photon emission computerized tomography (SPECT) respectively. The combined presence of certain symptoms and the use of these imaging techniques are considered early markers of PD in individuals with iRBD. In this study the investigators want to learn about the effect of treatment with the adrenergic blocker terazosin on MIBG abnormalities in iRBD patients at risk to develop PD. The investigators believe that reversing the MIBG abnormality might prelude to a slowing of the neurodegenerative process. This drug is approved by the U.S. Food and Drug Administration (FDA) for Benign Prostatic Hyperplasia (BPH) and Hypertension. However, terazosin is not approved by the FDA in patients with iRBD at risk for PD. The available doses for this drug oral formulations are 1mg, 2 mg, 5mg and 10 mg. Changes visualized with the MIBG imaging technique will be correlated to the presence and severity of neurological (i.e. tremors, stiffness, slow movements, walking difficulties) and other symptoms associated with PD (i.e. abnormal smell, constipation, depression, color vision abnormalities), as measured by specific clinical scales and exams.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
15
Fifteen patients with defined pre-motor PD risk and abnormal baseline 123I-MIBG uptake, with or without 123I-Ioflupane uptake abnormality or PD motor symptoms, will be recruited to receive daily oral doses of terazosin 5 mg or 10 mg. The dosage of terazosin will be gradually increased from the initial recommended starting dose of 1 mg daily at bedtime and titrated stepwise to 2mg, 5mg or 10 mg weekly, according to patient tolerability, as measured by subjective complaints, arterial blood pressure and heart rate. The target dose will be 5 mg or 10 mg daily based on subject's tolerability. Development of incompatibility will be addressed by individually adjusting the dose of terazosin.
Michele L Lima Gregorio
Los Angeles, California, United States
RECRUITINGDifferences in 123I-MIBG reuptake, as measured by early and late Heart to mediastinum (H/M) ratio, and Washout Ration (WR), at 26 weeks of treatment with the adrenergic blocker terazosin
1\) Differences in 123I-MIBG reuptake, as measured by early and late H/M ratio, and WR, at 26 weeks of treatment with the adrenergic blocker Terazosin.
Time frame: At baseline and at 26 weeks after medication titration
Incidence of adverse events
Safety will be monitored collecting the type and frequency of adverse events, including clinical symptoms
Time frame: At baseline and at 26 weeks after medication titration
Heart Rate variability changes from baseline at 26 weeks after study medication titration
Beat-to-beat intervals will be registered to assess sympatho-vagal balance.
Time frame: At baseline and at 26 weeks after medication titration
Incidence of abnormal vital signs
Changes in vital signs (Blood pressure and Heart rate)
Time frame: At baseline and at 26 weeks after medication titration
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