Vumez 20mg capsules
COMPOSITION Each tablet contains :
- Omeprazole U.S.P 20 mg.
- As enteric coated granules
PROPERTIES
Gastro-intestinal drug, proton pump inhibitor.
PHARMACOKINETICS
Omeprazole is rapidly absorbed, but to a variable extent, following oral administration. Absorption of omeprazole is not affected by food. Omeprazole is acid-labile and various formulations have been developed in an attempt to improve bioavailability from the gastro-intestinal tract. Consequently, its pharmacokinetics may vary with different formulations of die drug. The absorption of omeprazole, as well as being formulation-dependent, also appears to be dose-dependent, as increasing the dosage above 40 mg has been reported to increase the plasma concentrations in a non-linear fashion.
Bioavailability of omeprazole may be increased in elderly patients, in some ethnic groups such as Chinese, and in patients with impaired hepatic function, but is not markedly affected in patients with renal impairment. Following absorption, omeprazole is almost completely metabolised in the liver, primarily by cytochrome P450 isoform CYP2C19, and rapidly eliminated, mostly in the urine. Although the elimination half-life from plasma is short, being reported to be about 0.5 to 3 hours, its duration of action with regard to inhibition of acid secretion is much longer allowing it to be used in single daily doses. Omeprazole is highly bound (about 95%) to plasma proteins.
INDICATION
Doudenal and gastric ulcers, reflux or ulcerative oesophagitis. Zollinger-Ellison syndrome. NSAID-induced ulcers.
Onset of action : 2-5 hours.
Duration of action : 24 hours.
DOSAGE
Adults :
- (i) Gastric ulcer : 20 mg once daily for 8 wks, in severe cases increase to 40 mg once daily.
- (ii) Gastric ulcer : 20 mg once daily for 8 wks, in severe cases increase to 40 mg once daily.
- (iii) Doudenal ulcer : 20 mg once daily for 4 wks.
- (iv) Zollinger Ellison syndrome : 60 mg once daily. Maintenance therapy 20-120 mg adjusted to response, doses over 80 mg daily should be divided in 2 doses.
Children: Not recommended.
Drug interaction :Neuromuscular blocking agents (e.g. tubocurarine)enhanced.
- (i) Diazepam : Half-life of diazepam is increased.
- (ii) Phenytoin : Increased plasma concentration of phenytoin.
- (iii) Oral anticoagulants : May prolong the elimination of warfarin.
- (iv) Cyclosporine, disulfiram : Omeprazole interferes with metabolism of these drugs.
- (v) Ketoconazole, Ampicillin esters, iron salts : Omeprazole may interfere with absorption of these drugs where gastric pH is a determinant of their bioavailability.
SIDE EFFECTS
Nausea, constipation, diarrhoea, skin rash, headache.
PRECAUTIONS
Exclude gastric malignancy. Renal and hepatic dysfunction. Before giving omeprazole to patients with gastric ulcers the possibility of malignancy should be considered since omeprazole may mask symptoms and delay diagnosis. Omeprazole is extensively metabolized in the liver and some sources recommended that dosage should be reduced in hepatic impairment.
CONTRA-INDICATION
Hypersensitivity, neonates.
PHARMACEUTICAL PRECAUTION
Omeprazole capsules should be stored in a cool, dry and dark place.
PRESENTATION
Blister pack of 1 x 10 capsules.