Antiparkinsonian agents

Oxazolidinones and dihydrofuranones as inactivators and substrates of monoamine oxidase B, approaches to the design of antiparkinsonian agents 97F343. 

Maggio R, Scarselli M, Novi F, Millan MJ, Corsini GU. Potent activation of dopamine D3/D2 heterodimers by the antiparkinsonian agents, S32504, pramipexole and ropinirole. J Neurochem 2003 87 631-641. 

Anticholinergic agents antihistamines, antiparkinsonian agents, tricyclic antidepressants, pheno-thiazines... 

Symptomatic treatment in parkinsonism for the purpose of restoring a dopaminergic-cholinergic balance in the corpus striatum. Antiparkinsonian agents, such as benzatropine (p. 188), readily penetrate the blood-brain barrier. At centrally equi-effective dosage, their peripheral effects are less marked than are those of atropine. 

Central Motor restlessness, progressing to maniacal agitation, psychic disturbances, disorientation, and hallucinations. Elderly subjects are more sensitive to such central effects, in this context, the diversity of drugs producing atropine-like side effects should be borne in mind e.g., tricyclic antidepressants, neuroleptics, antihistamines, antiarrhythmics, antiparkinsonian agents. 

Administration of levodopa plus carbidopa (or benserazide) remains the most effective treatment, but does not provide benefit beyond 3-5 y and is followed by gradual loss of symptom control, on-off fluctuations, and development of orobuccofacial and limb dyskinesias. These long-term drawbacks of levodopa therapy may be delayed by early monotherapy with dopamine receptor agonists. Treatment of advanced disease requires the combined administration of antiparkinsonian agents. 

Reserve prolonged administration of doses exceeding 24 mg/day for hospitalized patients or patients under continued observation for early detection and management of adverse reactions. An antiparkinsonian agent, such as trihexyphenidyl hydrochloride or benztropine mesylate, is valuable in controlling drug-induced extrapyramidal symptoms. 

Bromocriptine (Parl el) [Antiparkinsonian Agent/Dopamine Receptor Agonist] Uses Parkin on Dz, hyperprolactinemia, acromegaly, pituitary tumors Action Direct-acting on the striatal dopamine receptors X prolactin secretion Dose Initial, 1.25 mg PO bid titrate to effect, w/ food Caution [B, ] Contra Severe ischemic heart Dz or PVD Disp Tabs, caps SE X BP, Raynaud phenomenon (vasospastic disorder resulting in discoloration of the fmgers/toes), dizziness, N, hallucinations Interactions T Effects W/ erythromycin, fluvoxamine, nefazodone, sympathomimetics, antihypertensives X effects W/ phenothiazines, antipsychotics EMS Monitor BP may cause intolerance to EtOH OD May cause NA, severe hypotension give IV fluids symptomatic and supportive... 

Common pharmacodynamic interactions involve the additive anticholinergic or antidopaminergic effects of antipsychotics. Thus, concomitantly administered antiparkinsonian agents (e.g., benztropine) may increase the chances of toxicity (e.g., delirium) while dopamimetic agents (e.g., levodopa) may counteract the antipsychotic or neurotoxic effects of these agents. 

Chien CP, DiMascio A, Cole JO. Antiparkinsonian agents and depot phenothiazine. Am J Psychiatry 1974 131 86-90. 

Avoidance of routine prophylaxis with antiparkinsonian agents, including benztropine, diphenhydramine, and amantadine, all of which have been associated with congenital anomalies. Calcium supplementation may be a useful alternative (10), and propranolol or atenolol may be used for akathisia if cardiovascular status is stable (7). 

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