Oxaprotiline (developmental code name C 49-802 BDA), also known as hydroxymaprotiline, is a norepinephrine reuptake inhibitor of the tetracyclic antidepressant (TeCA) family that is related to maprotiline. Though investigated as an antidepressant, it was never marketed.
Pharmacology [ ]
Dextroprotiline acts as a
potent norepinephrine reuptake inhibitor  and  H 1 receptor antagonist, as well as a very weak  α 1-adrenergic receptor antagonist.  It has negligible  affinity for the serotonin transporter,  dopamine transporter, α, 2-adrenergic receptor  and  muscarinic acetylcholine receptors. Whether it has any  antagonistic effects on the 5-HT, 2 5-HT, or 7 D like its relative 2 receptors maprotiline is unclear.
Levoprotiline acts as a
selective H 1 receptor antagonist, with no affinity for adrenaline, dopamine, muscarinic acetylcholine, or serotonin receptors, or any of the monoamine transporters.  
Chemistry [ ]
Oxaprotiline is a
racemic compound composed of two isomers, R(−)- or levo- oxaprotiline ( levoprotiline; CGP-12,103-A), and S(+)- or dextro- oxaprotiline ( dextroprotiline; CGP-12,104-A). Both enantiomers are active, with the levo- form acting as an antihistamine and the dextro- form having an additional pharmacology (see above), but with both unexpectedly still retaining antidepressant effects.
See also [ ]
References [ ]
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Waldmeier PC, Baumann PA, Hauser K, Maitre L, Storni A (June 1982). "Oxaprotiline, a noradrenaline uptake inhibitor with an active and an inactive enantiomer". . Biochemical Pharmacology 31 (12): 2169–76. doi: 10.1016/0006-2952(82)90510-X. PMID 7115436.
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Reimann IW, Firkusny L, Antonin KH, Bieck PR (1993). "Oxaprotiline: enantioselective noradrenaline uptake inhibition indicated by intravenous amine pressor tests but not alpha 2-adrenoceptor binding to intact platelets in man". European Journal of Clinical Pharmacology. 44 (1): 93–5. doi: 10.1007/BF00315288. PMID 8382162. S2CID 22691825.
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Noguchi S, Inukai T, Kuno T, Tanaka C (June 1992). "The suppression of olfactory bulbectomy-induced muricide by antidepressants and antihistamines via histamine H1 receptor blocking". Physiology & Behavior. 51 (6): 1123–7. doi: 10.1016/0031-9384(92)90297-F. PMID 1353628. S2CID 29562845.
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Richelson E, Nelson A (July 1984). "Antagonism by antidepressants of neurotransmitter receptors of normal human brain in vitro". The Journal of Pharmacology and Experimental Therapeutics. 230 (1): 94–102. PMID 6086881.
Noguchi S, Fukuda Y, Inukai T (May 1992). "Possible contributory role of the central histaminergic system in the forced swimming model". Arzneimittel-Forschung. 42 (5): 611–3. PMID 1530672.