quinidine phenobarbital

**Quinidine phenobarbital** is a historical oral fixed-dose combination of the class Ia antiarrhythmic quinidine and the barbiturate phenobarbital, also indexed as quinidine barbiturate and quinidine phenylethylbarbiturate. Quinidine produces use-dependent cardiac sodium-channel blockade and inhibits potassium currents, slowing conduction and prolonging refractoriness; phenobarbital enhances inhibitory gamma-aminobutyric acid signaling through gamma-aminobutyric acid type A receptors and can inhibit excitatory AMPA-type glutamate receptors. The combination was marketed in tablet form, including as Natisedine, for rhythm-related palpitations and extrasystoles associated with anxiety, irritability, and insomnia. It is a 1:1 quinidine-phenobarbital complex with molecular formula C32H36N4O5. ([pubchem.ncbi.nlm.nih.gov](https://pubchem.ncbi.nlm.nih.gov/compound/Quinidine-phenobarbital))

Brand names

NatisedinaNatisedine

Other names

KSX9K2OBZ2KSX-9K2OBZ2KSX 9K2OBZ2phenobarbital quinidinequinidine 5-ethyl 5-phenyl barbituratequinidine5-ethyl 5-phenyl barbituratequinidine-5-ethyl 5-phenyl barbituratequinidine barbituratequinidine phenylethylbarbiturate