Land: Singapore
Språk: engelska
Källa: HSA (Health Sciences Authority)
Venlafaxine hydrochloride 169.7mg eqv. venlafaxine
PFIZER PRIVATE LIMITED
N06AX16
150 mg
CAPSULE
ORAL
Prescription Only
PFIZER IRELAND PHARMACEUTICALS
2000-12-19
EFEXOR*XR (venlafaxine hydrochloride) Extended-Release Capsules PHARMACOLOGICAL CLASSIFICATION _Antidepressant _ DESCRIPTION Venlafaxine hydrochloride is a structurally novel antidepressant for oral administration. It is designated (R/S)-1-[2-(dimethylamino)-1-(4-methoxyphenyl) ethyl] cyclohexanol hydrochloride or (±)-1-[ α- [(dimethylamino)methyl]-p-methoxybenzyl] cyclohexanol hydrochloride and has the empirical formula C 17 H 27 NO 2 HCl. Its molecular weight is 313.87. The structural formula is shown below. Venlafaxine hydrochloride is a white to off-white crystalline solid with a solubility of 572 mg/mL in water (adjusted to ionic strength of 0.2 M with sodium chloride). Its octanol:water (0.2 M sodium chloride) partition coefficient is 0.43. Efexor XR is formulated as an extended-release capsule for once-a-day oral administration. Drug release is controlled by diffusion through the coating membrane on the spheroids and is not pH dependent. Capsules contain venlafaxine HCI equivalent to 75 mg or 150 mg venlafaxine. CLINICAL PHARMACOLOGY PHARMACODYNAMICS The mechanism of the antidepressant action of venlafaxine in humans is believed to be associated with its potentiation of neurotransmitter activity in the central nervous system. Preclinical studies have shown that venlafaxine and its major metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of neuronal serotonin and norepinephrine reuptake, and weak inhibitors of dopamine reuptake. Animal studies indicate that tricyclic antidepressants may reduce β-adrenergic receptor responsiveness following chronic administration. In contrast, venlafaxine and O- desmethylvenlafaxine reduce β-adrenergic responsiveness after both acute (single dose) and chronic administration. These results may predict a more rapid onset of Läs hela dokumentet