The invention provides (+)-α-dihydrotetrabenazine succinate salt. Also provided are (+)-α-dihydrotetrabenazine succinate salt for use in medicine, pharmaceutical compositions comprising (+)-α-dihydrotetrabenazine succinate salt and a pharmaceutically acceptable excipient and the uses of (+)-α-dihydrotetrabenazine succinate salt as a VMAT2 receptor antagonist and in the treatment of a movement disorder such as Tourette's syndrome. The invention further provides a method for preparing the (+)-α-dihydrotetrabenazine succinate salt.

A fused tricyclic compound and use thereof as a medicament, in particular as a medicament for the treatment and/or prevention of hepatitis B. Specifically, a compound having Formula (I) or a stereoisomer, a tautomer, an N-oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof, wherein each variate is as defined in specification. The compound also includes a Formula (I) or a stereoisomer, a tautomer, an N-oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof as a medicament, especially as a medicament for the treatment and/or prevention of hepatitis B. ##STR00001##

A fused tricyclic compound and use thereof as a medicament, in particular as a medicament for the treatment and/or prevention of hepatitis B. Specifically, a compound having Formula (I) or a stereoisomer, a tautomer, an N-oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof, wherein each variate is as defined in specification. The compound also includes a Formula (I) or a stereoisomer, a tautomer, an N-oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof as a medicament, especially as a medicament for the treatment and/or prevention of hepatitis B. ##STR00001##

Provided are methods of administering a vesicular monoamine transport 2 (VMAT2) inhibitor chosen from valbenazine and (+)--3-isobutyl-9,10-dimethoxy-1, 3,4, 6,7,11 b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ol, or a pharmaceutically acceptable salt and/or isotopic variant thereof, to a patient in need thereof wherein the patient is a CYP2D6 poor metabolizer.

The present invention provides novel compounds having the general formula: wherein R.sup.1, R.sup.2, X, Y and A are as described herein, compositions including the compounds and methods of using the compounds.

##STR00001##

The present invention provides novel compounds having the general formula: wherein R.sup.1, R.sup.2, X, Y and A are as described herein, compositions including the compounds and methods of using the compounds.

##STR00001##

Provided are methods of administering a vesicular monoamine transport 2 (VMAT2) inhibitor chosen from valbenazine and (+)--3-isobutyl-9,10-dimethoxy-1,3,4,6,7,1 1b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ol, or a pharmaceutically acceptable salt and/or isotopic variant thereof, to a patient in need thereof wherein the patient is also being administered digoxin.

A novel process for preparation of Deutetrabenazine ((RR, SS)-1,3,4,6,7-11b-Hexahydro-9,10-di(methoxy-d.sub.6)-3-(2-methylpropyl)-2H- benzo [a] quinolizin-2-one) of formula I comprises of methylation of N-(2-(3,4-dihydroxy-phenyl)-ethyl)-formamide compound of formula III with deuteriated methanol (CD.sub.3OD or CD.sub.3OH) to obtain d.sub.6-N-(2-(3,4-dimethoxy-phenyl)-ethyl)-formamide compound of formula IV; cyclization of d.sub.6-N-(2-(3,4-dimethoxy-phenyl)-ethyl)-formamide in presences of dehydrating agent to obtain d.sub.6-6,7-Dimethoxy-3,4-dihydroisoquinoline compound of formula V; reacting d.sub.6-6,7-Dimethoxy-3,4-dihydroisoquinoline compound of formula V with 2-acetyl-N,N,N,4-tetramethyl-1-pentanaminium iodide compound of formula VI.

A novel process for preparation of Deutetrabenazine ((RR, SS)-1,3,4,6,7-11b-Hexahydro-9,10-di(methoxy-d.sub.6)-3-(2-methylpropyl)-2H- benzo [a] quinolizin-2-one) of formula I comprises of methylation of N-(2-(3,4-dihydroxy-phenyl)-ethyl)-formamide compound of formula III with deuteriated methanol (CD.sub.3OD or CD.sub.3OH) to obtain d.sub.6-N-(2-(3,4-dimethoxy-phenyl)-ethyl)-formamide compound of formula IV; cyclization of d.sub.6-N-(2-(3,4-dimethoxy-phenyl)-ethyl)-formamide in presences of dehydrating agent to obtain d.sub.6-6,7-Dimethoxy-3,4-dihydroisoquinoline compound of formula V; reacting d.sub.6-6,7-Dimethoxy-3,4-dihydroisoquinoline compound of formula V with 2-acetyl-N,N,N,4-tetramethyl-1-pentanaminium iodide compound of formula VI.

Provided are methods of administering a vesicular monoamine transport 2 (VMAT2) inhibitor chosen from valbenazine and (+)--3-isobutyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ol, or a pharmaceutically acceptable salt and/or isotopic variant thereof to a patient in need thereof wherein the patient is being treated with a strong cytochrome P450 3A4 (CYP3A4) inducer.