Rabeprazole

BRAND NAMES:

Aciphex – Aciphex contains Rabeprazole sodium as the active ingredient available in the market as Aciphex delayed-release tablets 20 mg. 

Pariet – It is also available in the form of tablets with rabeprazole sodium as the main active ingredient.

MECHANISM OF ACTION:

Rabeprazole sodium works by inhibiting the proton pump within the stomach lining, which reduces gastric acid production. The function of the proton pump is also known as the H+/K+ ATPase enzyme. This enzyme is found in the stomach's parietal cells and is responsible for gastric acid production. The proton pump converts hydrogen ions (H+) from the parietal cells into potassium ions (K+) from the stomach lumen. Rabeprazole targets this proton pump directly. It is absorbed in the small intestine and transferred to parietal cells in inactive form. After reaching the acidic environment of the parietal cells, Rabeprazole sodium is protonated and converted into its active sulphonamide form. The activated form then covalently binds to cysteine residues on the H+/K+ATPase enzyme, inhibiting its activity. By blocking the enzyme, rabeprazole sodium prevents the secretion of hydrogen ions into the stomach, thereby reducing gastric acid production.

PHARMACOKINETICS:

Absorption: It takes 3 to 4 hours to achieve its maximum plasma concentration. The absolute bioavailability of oral administration is around 52%.

Metabolism: It passes through a comprehensive, mostly non-enzymatic metabolism, with the metabolites eliminated by the kidneys. CYP3A4 and CYP2C19 contribute to enzymatic metabolism

Excretion: 90% of the drug is eliminated through urine.

PHARMACODYNAMICS:

It lowers esophageal damage and stomach ulcers in people with gastro-oesophageal reflux disease by stopping the stomach from producing acid. The selective and irreversible proton pump inhibitor rabeprazole inhibits the production of stomach acid by specifically inhibiting H+, K+ -ATPase, which is present on the surface of parietal cells. It prevents hydrogen ions from entering the stomach lumen in their final state.

DOSAGE AND ADMINISTRATION:

Rabeprazole is available in the form of oral capsules and tablets

• For gastroesophageal reflux, the dosage form for adults aged above 18 years is 20mg dosage is recommended once in a day. In children between 12 – 17 years, the recommended dosage is 20mg once a day.
• For patients suffering from duodenal ulcers the recommended dose for adults above 18 years is 20mg daily after the meal up to 4 weeks.
• Adult patients with Helicobacter pylori should take 20 mg twice a day as recommended. This medication is used in conjunction with clarithromycin and amoxicillin.
• For Zollinger-Ellison syndrome, the recommended dose in adults is 60mg once a day and the maximum dosage is 100mg once a day or 60mg twice a day.

DRUG INTERACTIONS:

Before using rabeprazole it is required to discuss with the doctor the medications which have been used for another treatment. Taking rabeprazole with other medicines may interact and decrease the functioning of the drug and also cause some adverse effects. Below are some medicines which interact with the rabeprazole

• Pain killer  - Aspirin, Naproxen
• Anti -HIV – Atazanavir
• Blood thinner – Clopidogrel
• Anti- fungal – Ketoconazole, Itraconazole
• Antidepressant – Duloxetine, amitriptyline
• Hyperthyroidism – Levothyroxine
• Anti cancer -  Methotrexate
• Vitamin -  Cyanocobalamin
• Medicines for sleeping – Diazepam, Zolpidem

FOOD INTERACTIONS:

Avoid smoking and alcohol as intake of alcohol leads to stomach acid thereby increasing acidity and heartburn.

ADVERSE EFFECTS:

• Sore throat
• Constipation
• Hives
• Irregular heartbeat
• Nausea
• Vomiting
• Headache
• Diarrhea
• Swollen glands
• Muscle spams
• Worsening of joint pains
• Increased or decreased urination
• Loss of appetite
• Hoarness
• Difficulty in breathing and swallowing
• Swelling of eyes, throat, lips and mouth
• Flu symptoms
• Blistering
• Bleeding
• Shortness of breath

TOXICITY:

Overdose of rabeprazole can cause some toxic effects.

• Seizures
• Trouble in breathing
• Sudden death