| Item |
Information |
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Drug Groups
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approved |
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Description
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A muscarinic antagonist used to treat drug-induced parkinsonism and to relieve pain from muscle spasm. [PubChem] |
| Indication |
Indicated for the treatment of Parkinson's disease. |
| Pharmacology |
Orphenadrine is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions. Orphenadrine is an anticholinergic with a predominantly central effect and only a weak peripheral effect. In addition, it has mild antihistaminic and local anaesthetic properties. Parkinson's syndrome is the consequence of a disturbed balance between cholinergic and dopaminergic neurotransmission in the basal ganglia caused by a decrease in dopamine. Orphenadrine restores the physiological equilibrium and has a favourable effect on the rigidity and tremor of Parkinson's disease and Parkinsonian syndromes. The effect is somewhat less on bradykinesia. |
| Toxicity |
Oral, mouse LD50 = 100 mg/kg; oral, rat LD50 = 255 mg/kg |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Biotransformation occurs mainly in the liver. Pharmacologically active metabolites are N-demethyl orphenadrine and N,N-didemethyl orphenadrine. |
| Absorption |
Orphenadrine is almost completely absorbed in the gastrointestinal tract. |
| Half Life |
13-20 hours |
| Protein Binding |
95% |
| References |
| • |
Ji D, Sui ZY, Ma YY, Luo F, Cui CL, Han JS: NMDA receptor in nucleus accumbens is implicated in morphine withdrawal in rats. Neurochem Res. 2004 Nov;29(11):2113-20.
[Pubmed]
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| External Links |
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