Oxaprotiline, also known as hydroxymaprotiline, is a psychoactive drug and research chemical of the tetracyclic chemical class. Though investigated as an antidepressant, it was never developed and marketed for clinical use.

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 merely as an antihistamine and the dextro- form having a more expansive pharmacology (see below), but with both curiously still retaining antidepressant effects.

Dextroprotiline acts as a potent norepinephrine reuptake inhibitor and H₁ receptor antagonist, as well as a very weak α₁-adrenergic receptor antagonist. It has negligible affinity for the serotonin transporter,dopamine transporter, α₂-adrenergic receptor, and muscarinic acetylcholine receptors. Whether it has any antagonistic effects on the 5-HT₂ or D₂ receptors like its relative maprotiline is unclear.