Description
PHARMACOLOGY
1.OMEPRAZOLE
a.)Pharmacodynamics: – After oral administration, the onset of the anti-secretory effect of omeprazole occurs within one hour and maximum effect occurring within two hours. At 24 hours, inhibition of secretion is approximately 50% of maximum and duration of inhibition lasts up to 72 hours. Although omeprazole has a very short plasma half-life, the anti-secretory effect lasts for a long time due to prolonged binding to parietal H+/K+ ATPase enzyme. When the drug has been discontinued, secretory activity will return to baseline over 3-5 days. The inhibitory effect of omeprazole on acid secretion increases with repeated once-daily dosing, reaching a plateau after four days. In studies involving more than 200 patients, serum gastrin levels increased during the first 1 to 2 weeks of once-daily administration of therapeutic doses of omeprazole in parallel with inhibition of acid secretion. Systemic effects of omeprazole in the CNS, cardiovascular and respiratory systems have not been found to date.
b.)Pharmacokinetics:-
- Absorption: Omeprazole is well absorbed after oral administration.
- Distribution: It is widely distributed in the body in protein bound form.
- Metabolism: Omeprazole is extensively metabolized in the liver.
- Excretion: It is excreted mainly in the feces and small amount in urine.
2.DOMPERIDONE
a.)Pharmacodynamics: –
Mechanism of Action:
Domperidone is a potent dopamine receptor antagonist. It acts centrally and blocks the Dopamine receptor in the Chemoreceptor trigger zone and produces Antiemetic effect.
Domperidone acts peripherally in the gastrointestinal system and increases esophageal peristalsis, esophageal sphincter pressure and gastric motility. These all facilitates gastric emptying. Domperidone is used in migraine to relieve nausea and vomiting.
Anesthetic adjuncts: It is used preoperatively in order to reduce the post operative vomiting.
b.)Pharmacokinetics: –
- Absorption: Domperidone is rapidly absorbed after oral administration. Since it undergoes first pass metabolism oral bioavailability is only 15 %.
- Distribution: It is widely distributed in the body in protein bound form.
- Metabolism: Domperidone undergoes metabolism in the liver.
- Excretion: It is excreted mainly in the feces and also in the urine.
INDICATIONS:
OMEPRAZOLE
- Duodenal ulcer
- Gastric ulcer
- Zollinger- Ellison syndrome
- Gastroesophageal reflux disease
- Oesophagitis
- Acid related dyspepsia
- NSAID associated ulceration
- Prophylaxis of acid aspiration during anesthesia
DOMPERIDONE:
- Nausea and vomiting associated with gastrointestinal disorder and migraine.
- Delayed gastric emptying of functional origin.
- As an Antiemetic in patient receiving cytotoxic drugs.
- Pre-anesthetic medication.
