Thioxanthenes Levodopa

Antiadrenergic] Uses HTN Action Centrally acting antihypCTtensive Dose Adults. 250-500 mg PO bid-tid (max 2-3 g/d) or 250 mg-1 g IV q6-8h Peds. 10 mg/kg/24 h PO in 2-3 doses (max 40 mg/kg/24 h q6-12h) or 5-10 mg/kg/dose IV q6-8h to total dose of 20 0 mg/kg/24 h X in renal insuff/elderly Caution [B (PO), C (IV), +] Contra Liver Dz MAOIs Disp Tabs, inj SE Discolors urine initial transient sedation/drowsiness frequent, edema, hemolytic anemia, hepatic disorders Interactions T Effects W/ anesthetics, diuretics, levodopa, Li, methotrimeprazine, thioxanthenes, vasodilators, verapamil T effects OF haloperidol, Li, tolbutamide effects W/amphetamines, Fe, phenothiazine, TCAs ... 

Phenothiazines, butyrophenones, diphenylbutylpiperidines and thioxanthenes can oppose the effects of levodopa because of their dopamine antagonist properties, causing deterioration of motor function in Parkinson s disease. The antipsychotic effects and ex-trapyramidal adverse effects of these drugs can be opposed by levodopa. Of the atypical antipsychotics, risperidone and olanzapine cause deterioration in motor function in Parkinson s disease. Ziprasidone may act similarly, and there have been reports with quetiapine. Clozapine does not have this effect. 

---