Careful Administration: PARIET should be administered with care in the following patients: Patients with a history of drug hypersensitivity; Patients with hepatic function disorder [Psychoneurotic adverse reactions have been reported in patients with liver cirrhosis (see Adverse Reactions)]; Elderly patients (see Use in the Elderly as follows).
Important Precautions: PARIET can be administered at a dose of 20 mg once daily in the case of severe, recurrent and intractable conditions.
Precautions concerning Use: Regular Surveillance: Patients on proton pump inhibitor treatment (particularly those treated for long term) should be kept under regular surveillance.
Administration: Since PARIET is an enteric coated tablet, patients should be instructed not to chew or crush the tablet, but swallow it whole.
Caution in handing over drug: For drugs that are dispensed in a press-through package (PTP), instruct the patient to remove the drug from the package prior to use. [It has been reported that, if the PTP sheet is swallowed, the sharp corners of the sheet may puncture the esophageal mucosa, causing perforation and resulting in serious complications such as mediastinitis.]
Other Precautions: It has been reported that in a carcinogenicity study in which 5mg/kg/day or greater of sodium rabeprazole was administered orally to rats for 2 years, carcinoids were observed in the stomachs of female rats.
Increases in thyroid weight and blood thyroxine levels have been reported in animal studies (rats, oral administration of 25mg/kg/day or greater). Therefore, thyroid function should be carefully monitored during the administration of PARIET.
Benign gastric polyp has been reported during long-term administration of PARIET.
Fracture: Proton pump inhibitors, especially if used in high doses and over long durations (>1 year), may modestly increase the risk of hip, wrist and spine fracture, predominantly in older people or in presence of other recognised risk factors. Observational studies suggest that proton pump inhibitors may increase the overall risk of fracture by 10-40%. Some of this increase may be due to other risk factors. Patients at risk of osteoporosis should receive care according to current clinical guidelines and they should have an adequate intake of vitamin D and calcium.
Clostridium difficile Diarrhea: Published observational studies suggest that PPI therapy may be associated with an increased risk of Clostridium difficile associated diarrhea, especially in hospitalized patients. This diagnosis should be considered for diarrhea that does not improve.
Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated.
Interference with laboratory test: Increased Chromogranin A (CgA) level may interfere with investigations for neuroendocrine tumours.
To avoid this interference, PARIET treatment should be stopped for at least 5 days before CgA measurements (see Pharmacology: Adjunctive effect on Helicobacter pylori Eradication under Actions). If CgA and gastrin levels have not returned to reference range after initial measurement, measurements should be repeated 14 days after cessation of proton pump inhibitor treatment.
Subacute cutaneous lupus erythematosus (SCLE): Proton pump inhibitors are associated with very infrequent cases of SCLE. If lesions occur, especially in sun-exposed areas of the skin, and if accompanied by arthralgia, the patient should seek medical help promptly and the health care professional should consider stopping PARIET. SCLE after previous treatment with a proton pump inhibitor may increase the risk of SCLE with other proton pump inhibitors.
Hypomagnesaemia: Severe hypomagnesaemia has been reported in patients treated with proton pump inhibitors like PARIET for at least three months, and in most cases for a year.
Serious manifestations of hypomagnesaemia such as fatigue, tetany, delirium, convulsions, dizziness and ventricular arrhythmia can occur but they may begin insidiously and be overlooked. In most affected patients, hypomagnesaemia improved after magnesium replacement and discontinuation of the PPI.
For patients expected to be on prolonged treatment or who take PPI with digoxin or drugs that may cause hypomagnesaemia (e.g., diuretics), health care professionals should consider measuring magnesium levels before starting PPI treatment and periodically during treatment.
Vitamin B12 Deficiency: Daily treatment with any acid-suppressing medications over a long period of time (e.g., longer than 3 years) may lead to malabsorption of cyanocobalamin (vitamin B-12) caused by hypo- or achlorhydria. Rare reports of cyanocobalamin deficiency occurring with acid-suppressing therapy have been reported in the literature. This diagnosis should be considered if clinical symptoms consistent with cyanocobalamin deficiency are observed.
Effects on ability to drive and use machines: Based on the pharmacodynamic properties and the adverse events profile, it is unlikely that PARIET would cause an impairment of driving performance or compromise the ability to use machinery. If however, alertness is impaired due to somnolence, it is recommended that driving and operating complex machinery be avoided.
Use in the Elderly: PARIET is metabolized mainly in the liver. Since the physiological functions of the liver are often reduced in the elderly, they are more likely to experience adverse reactions. Therefore, if adverse reactions such as gastrointestinal symptoms (see Adverse Reactions) occur, it is advisable to take measures such as instituting a drug-free interval with careful supervision.
Use in Pregnancy & Lactation: There are no data on the safety of rabeprazole in human pregnancy. Reproduction studies performed in rats and rabbits have revealed no evidence of impaired fertility or harm to the foetus due to rabeprazole sodium, although low foeto-placental transfer occurs in rats. PARIET is contraindicated during pregnancy.
[Fetotoxicity (delayed ossification in rats, weight loss and delayed ossification in rabbits) has been reported with PARIET in animal studies (400 mg/kg p.o. in rats, 30 mg/kg i.v. in rabbits).]
It is not known whether rabeprazole sodium is excreted in human breast milk. No studies in lactating women have been performed. Rabeprazole sodium is however excreted in rat mammary secretions. Therefore PARIET should not be used during breast feeding.
[In an animal study (in rats), it has been reported that PARIET is excreted in breast milk.]
Use in Children: PARIET is not recommended for use in children, as there is no experience of its use in this group.