Oxaprotiline (developmental code name C 49-802 BDA), also known as hydroxymaprotiline, is a norepinephrine reuptake inhibitor belonging to the tetracyclic antidepressant (TeCA) family and is related to maprotiline.

Dextroprotiline acts as a potent norepinephrine reuptake inhibitor[2][3] and H1 receptor antagonist,[4] as well as a very weak α1-adrenergic receptor antagonist.

[5] Whether it has any antagonistic effects on the 5-HT2, 5-HT7, or D2 receptors like its relative maprotiline is unclear.

Levoprotiline acts as a selective H1 receptor antagonist, with no affinity for adrenaline, dopamine, muscarinic acetylcholine, or serotonin receptors, or any of the monoamine transporters.

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.