Pantoprazole (EC)

IT IS A PROTONE PUMP INHIBITOR, I.E. IT INHIBITS SPECIFICALLY AND DOSE PROPORTIONALLY THE GASTRIC H+, K+-AT PASE ENZYME WHICH IS RESPONSIBLE FOR ACID SECRETION IN THE PARIETAL CELLS OF THE STOMACH.

Dose:

1 TAB PER DAY, EITHER DURING OR BEFORE BREAKFAST. DUODENAL ULCER : 1 TAB FOR 2 WEEKS. GASTRIC ULCER : 1 TAB FOR 4 WEEKS. GASTRO-OESOPHAGEAL REFLUX : 1 TAB FOR 4 WEEKS. Monograph Pantoprazole Sodium DESCRIPTION: Pantoprazole sodium is a substituted benzimidazole, sodium 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]sulfinyl]-1H -benzimidazole sesquihydrate, a compound that inhibits gastric acid secretion. Its empirical formula is C16H14F2N3NaO4Sú1.5 H2O, with a molecular weight of 432.4. Pantoprazole sodium sesquihydrate is a white to off-white crystalline powder and is racemic. Pantoprazole has weakly basic and acidic properties. Pantoprazole sodium sesquihydrate is freely soluble in water, very slightly soluble in phosphate buffer at pH 7.4, and practically insoluble in n-hexane. The stability of the compound in aqueous solution is pH-dependent. The rate of degradation increases with decreasing pH. At ambient temperature, the degradation half-life is approximately 2.8 hours at pH 5.0 and approximately 220 hours at pH 7.8. Protonix is supplied as a delayed-release tablet for oral administration. Each delayed-release tablet contains 45.1 mg of pantoprazole sodium sesquihydrate (equivalent to 40 mg pantoprazole) with the following inactive ingredients: anhydrous sodium carbonate, mannitol, crospovidone, povidone, calcium stearate, hydroxypropyl methylcellulose, titanium dioxide, yellow iron oxide, propylene glycol, methacrylic acid copolymer, polysorbate 80, sodium lauryl sulfate, and triethyl citrate. CLINICAL PHARMACOLOGY: Pharmacokinetics Pantoprazole sodium is prepared as an enteric-coated tablet so that absorption of pantoprazole begins only after the tablet leaves the stomach. Peak serum concentration (Cmax) and area under the serum concentration time curve (AUC) increase in a manner proportional to oral and intravenous doses from 10 mg to 80 mg. Pantoprazole does not accumulate and its pharmacokinetics are unaltered with multiple daily dosing. Following oral or intravenous administration, the serum concentration of pantoprazole declines biexponentially with a terminal elimination half-life of approximately one hour. In extensive metabolizers (see Metabolism) with normal liver function receiving an oral dose of the enteric-coated 40 mg pantoprazole tablet, the peak concentration (Cmax) is 2.4 mug/ml, the time to reach the peak concentration (tmax) is 2.4 hour and the total area under the plasma concentration versus time curve (AUC) is 4.8 mugúhr/ml. When pantoprazole is given with food, its tmax is highly variable and may increase significantly. Following intravenous administration of pantoprazole to extensive metabolizers, its total clearance is 7.6-14.0 L/hr and its apparent volume of distribution is 11.0-23.6 L. Absorption The absorption of pantoprazole is rapid, with a Cmax of 2.5 mug/ml that occurs approximately 2.5 hours after single or multiple oral 40 mg doses. Pantoprazole is well absorbed; it undergoes little first-pass metabolism resulting in an absolute bioavailability of approximately 77%. Pantoprazole absorption is not affected by concomitant administration of antacids. Administration of pantoprazole with food may delay its absorption up to 2 hours or longer; however, the Cmax and the extent of pantoprazole absorption (AUC) are not altered. Thus, pantoprazole may be taken without regard to timing of meals. Distribution The apparent volume of distribution of pantoprazole is approximately 11.0-23.6 L, distributing mainly in extracellular fluid. The serum protein binding of pantoprazole is about 98%, primarily to albumin. Metabolism Pantoprazole is extensively metabolized in the liver through the cytochrome P450 (CYP) system. Pantoprazole metabolism is independent of the route of administration (intravenous or oral). The main metabolic pathway is demethylation, by CYP2C19, with subsequent sulfation; other metabolic pathways include oxidation by CYP3A4. There is no evidence that any of the pantoprazole metabolites have significant pharmacologic activity. CYP2C19 displays a known genetic polymorphism due to its deficiency in some sub-populations (e.g., 3% of Caucasians and African-Americans and 17-23% of Asians). Although these sub-populations of slow pantoprazole metabolizers have elimination half-life values of 3.5-10.0 hours, they still have minimal accumulation (23%) with once daily dosing. Elimination After a single oral or intravenous dose of 14C-labeled pantoprazole to healthy, normal metabolizer volunteers, approximately 71% of the dose was excreted in the urine with 18% excreted in the feces through biliary excretion. There was no renal excretion of unchanged pantoprazole. Special Populations Geriatric: Only slight to moderate increases in pantoprazole AUC (43%) and Cmax (26%) were found in elderly volunteers (64-76 years of age) after repeated oral administration, compared with younger subjects. No dosage adjustment is recommended based on age. Pediatric: The pharmacokinetics of pantoprazole have not been investigated in patients <18 years of age. Gender: There is a modest increase in pantoprazole AUC and Cmax in women compared to men. However, weight-normalized clearance values are similar in women and men. No dosage adjustment is needed based on gender. (Also see PRECAUTIONS, Use in Women.) Renal Impairment: In patients with severe renal impairment, pharmacokinetic parameters for pantoprazole were similar to those of healthy subjects. No dosage adjustment is necessary in patients with renal impairment or in patients undergoing hemodialysis. Hepatic Impairment: In patients with mild to moderate hepatic impairment, maximum pantoprazole concentrations increased only slightly (1.5-fold) relative to healthy subjects. Although serum half-life values increased to 7-9 hours and AUC values increased by five-fold to seven-fold in hepatic-impaired patients, these increases were no greater than those observed in slow CYP2C19 metabolizers, where no dosage frequency adjustment is warranted. These pharmacokinetic changes in hepatic-impaired patients result in minimal drug accumulation following once daily multiple-dose administration. No dosage adjustment is needed in patients with mild or moderate hepatic impairment. The pharmacokinetics of pantoprazole have not yet been well characterized in patients with severe hepatic impairment. Therefore, the potential for modest drug accumulation (21%) when dosed once daily needs to be weighed against the potential for reduced acid control when dosed every other day in these patients. Drug-Drug Interactions Pantoprazole is metabolized mainly by CYP2C19 and to minor extents by CYPs 3A4, 2D6, and 2C9. In in vivo drug-drug interaction studies with CYP2C19 substrates (diazepam [also a CYP3A4 substrate] and phenytoin [also a CYP3A4 inducer]), nifedipine (a CYP3A4 substrate), metoprolol (a CYP2D6 substrate), diclofenac (a CYP2C9 substrate) and theophylline (a CYP1A2 substrate) in healthy subjects, the pharmacokinetics of pantoprazole were not significantly altered. It is, therefore, expected that other drugs metabolized by CYPs 2C19, 3A4, 2D6, 2C9, and 1A2 would not significantly affect the pharmacokinetics of pantoprazole. In vivo studies also suggest that pantoprazole does not significantly affect the kinetics of other drugs (cisapride, theophylline, diazepam [and its active metabolite, desmethyldiazepam], phenytoin, warfarin, metoprolol, nifedipine, carbamazepine and oral contraceptives) metabolized by CYPs 2C19, 3A4, 2C9, 2D6, and 1A2. Therefore, it is expected that pantoprazole would not significantly affect the pharmacokinetics of other drugs metabolized by these isozymes. Dosage adjustment of such drugs is not necessary when they are co-administered with pantoprazole. In other in vivo studies, digoxin, ethanol, glyburide, antipyrine, and caffeine had no clinically relevant interactions with pantoprazole. Pharmacodynamics Mechanism of Action Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production by forming a covalent bond to two sites of the (H+,K+)-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect is dose-related and leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The binding to the (H+,K+)-ATPase results in a duration of antisecretory effect that persists longer than 24 hours. Pantoprazole has the unique binding with cysteine 822 in parietal cells which leads to increased dwell time against acting proton pumps and more durable acid suppression specially at night time while other proton pump inhibitors has binding with cysteine 813. Antisecretory Activity Under maximal acid stimulatory conditions using pentagastrin, a dose-dependent decrease in gastric acid output occurs after a single dose of oral (20-80 mg) or a single dose of intravenous (20-120 mg) pantoprazole in healthy volunteers. Pantoprazole given once daily results in increasing inhibition of gastric acid secretion. Following the initial oral dose of 40 mg pantoprazole, a 51% mean inhibition was achieved by 2.5 hours. With once a day dosing for 7 days the mean inhibition was increased to 85%. Pantoprazole suppressed acid secretion in excess of 95% in half of the subjects. Acid secretion had returned to normal within a week after the last dose of pantoprazole; there was no evidence of rebound hypersecretion. In a series of dose-response studies pantoprazole, at oral doses ranging from 20-120 mg, caused dose-related increases in median basal gastric pH and in the percent of time gastric pH was >3 and >4. Treatment with 40 mg of pantoprazole produced optimal increases in gastric pH which were significantly greater than the 20 mg dose. Doses higher than 40 mg (60, 80, 120 mg) did not result in further significant increases in median gastric pH. A double-blind crossover study compared pantoprazole 40 mg with omeprazole 20 mg once daily for 7 days. For both one day and one week treatment periods, pantoprazole administered in the morning produced significantly greater increases in median pH during 24 hours than did omeprazole. Serum Gastrin Effects Fasting serum gastrin levels were assessed in two double-blind studies of the acute healing of erosive esophagitis (EE) in which 682 patients with gastroesophageal reflux disease (GERD) received 10, 20, or 40 mg of pantoprazole for up to 8 weeks. At 4 weeks of treatment there was an increase in mean gastrin levels of 7%, 35%, and 72% over pretreatment values in the 10, 20, and 40 mg treatment groups, respectively. A similar increase in serum gastrin levels was noted at the 8 week visit with mean increases of 3%, 26%, and 84% for the three pantoprazole dose groups. In long term studies involving over 800 patients, a two-fold to three-fold mean increase from the pretreatment fasting serum gastrin level was observed in the initial months of treatment with pantoprazole at doses of 40 mg per day during GERD maintenance studies and 40 mg or higher per day in patients with refractory GERD. Fasting serum gastrin levels generally remained at approximately 2-3 times baseline for up to 4 years of periodic follow-up in clinical trials. Following healing of gastric or duodenal ulcers with pantoprazole treatment, elevated gastrin levels return to normal by at least 3 months. Enterochromaffin-like (ECL) Cell Effects In 39 patients treated with oral pantoprazole 40-240 mg daily (majority receiving 40-80 mg) for up to 5 years, there was a moderate increase in ECL-cell density starting after the first year of use which appeared to plateau after 4 years. In a nonclinical study in Sprague-Dawley rats, lifetime exposure (24 months) to pantoprazole at doses of 0.5-200 mg/kg/day resulted in dose-related increases in gastric ECL-cell proliferation and gastric neuroendocrine (NE)-cell tumors. Gastric NE-cell tumors in rats may result from chronic elevation of serum gastrin levels. The high density of ECL cells in the rat stomach makes this species highly susceptible to the proliferative effects of elevated gastrin levels produced by proton pump inhibitors. However, there were no observed elevations in serum gastrin following the administration of pantoprazole at a dose of 0.5 mg/kg/day. In a separate study, a gastric NE-cell tumor without concomitant ECL-cell proliferative changes was observed in 1 female rat following 12 months of dosing with pantoprazole at 5 mg/kg/day and a 9-month off-dose recovery. (See PRECAUTIONS, Carcinogenesis, Mutagenesis, and Impairment of Fertility.) Other Effects No clinically relevant effects of pantoprazole on cardiovascular, respiratory, ophthalmic, or central nervous system function have been detected. In a clinical pharmacology study, pantoprazole 40 mg given once daily for 2 weeks had no effect on the levels of the following hormones: cortisol, testosterone, triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone, thyronine-binding protein, parathyroid hormone, insulin, glucagon, renin, aldosterone, follicle-stimulating hormone, luteinizing hormone, prolactin, and growth hormone. CLINICAL STUDIES: Pantoprazole sodium delayed-release tablets were used in all clinical trials. Erosive Esophagitis (EE) Associated with Gastroesophageal Reflux Disease (GERD): A US multicenter double-blind, placebo-controlled study of pantoprazole sodium 10 mg, 20 mg or 40 mg once daily was conducted in 603 patients with reflux symptoms and endoscopically diagnosed EE of grade 2 or above (Hetzel-Dent scale). In this study, approximately 25% of enrolled patients had severe EE of grade 3 and 10% had grade 4. In this study, all pantoprazole sodium treatment groups had significantly greater healing rates than the placebo group. This was true regardless of H. pylori status for the 20 mg and 40 mg pantoprazole sodium treatment groups. The 40 mg dose of pantoprazole sodium resulted in healing rates significantly greater than those found with either the 20 or 10 mg dose. A significantly greater proportion of patients taking pantoprazole sodium 40 mg experienced complete relief of daytime and nighttime heartburn and the absence of regurgitation starting from the first day of treatment compared with placebo. Patients taking pantoprazole sodium consumed significantly fewer antacid tablets per day than those taking placebo. Pantoprazole sodium 20 mg and 40 mg once daily was also compared with nizatidine 150 mg twice daily in a US multicenter, double-blind study of 243 patients with reflux symptoms and endoscopically diagnosed EE of grade 2 or above. Once daily treatment with pantoprazole sodium 20 or 40 mg resulted in significantly superior rates of healing at both 4 and 8 weeks compared with twice daily treatment with 150 mg of nizatidine. For the 40 mg treatment group, significantly greater healing rates compared to nizatidine were achieved regardless of the H. pylori status. A significantly greater proportion of the patients in the pantoprazole sodium treatment groups experienced complete relief of nighttime heartburn and regurgitation starting on the first day and of daytime heartburn on the second day compared with those taking nizatidine 150 mg twice daily. Patients taking pantoprazole sodium consumed significantly fewer antacid tablets per day than those taking nizatidine. INDICATIONS AND USAGE: Short-Term Treatment of Erosive Esophagitis Associated With Gastroesophageal Reflux Disease (GERD): Pantoprazole sodium delayed-release tablets are indicated for the short-term treatment (up to 8 weeks) in the healing and symptomatic relief of erosive esophagitis. For those patients who have not healed after 8 weeks of treatment, an additional 8 week course of pantoprazole sodium may be considered. The safety and efficacy of pantoprazole sodium for maintenance therapy (e.g., beyond 16 weeks) have not been established. (See PRECAUTIONS.) CONTRAINDICATIONS: Pantoprazole sodium delayed-release tablets are contraindicated in patients with known hypersensitivity to any component of the formulation. PRECAUTIONS: General Symptomatic response to therapy with pantoprazole does not preclude the presence of gastric malignancy. In rodents, pantoprazole is carcinogenic and caused rare types of gastrointestinal tumors. The relevance of these animal findings to humans is unknown. The safety and efficacy of pantoprazole sodium for maintenance therapy (e.g., beyond 16 weeks) have not been established. Pantoprazole sodium is not indicated for maintenance therapy. (See INDICATIONS AND USAGE.) No dosage adjustment is necessary in patients with mild or moderate hepatic impairment. The pharmacokinetics of pantoprazole has not been well characterized in patients with severe hepatic impairment. Therefore, the potential for modest drug accumulation (21%) when dosed once daily needs to be weighed against the potential for reduced acid control when dosed every other day in these patients. Information for the Patient Patients should be cautioned that pantoprazole sodium delayed-release tablets should not be split, crushed or chewed. The tablets should be swallowed whole, with or without food in the stomach. Concomitant administration of antacids does not affect the absorption of pantoprazole. Carcinogenesis, Mutagenesis, and Impairment of Fertility In a 24-month carcinogenicity study, Sprague-Dawley rats were treated orally with doses of 0.5-200 mg/kg/day, about 0.1-40 times the exposure on a body surface basis, of a 50-kg person dosed at 40 mg/day. In the gastric fundus, treatment at 0.5-200 mg/kg/day produced enterochromaffin-like (ECL) cell hyperplasia and benign and malignant neuroendocrine cell tumors in a dose-related manner. In the forestomach, treatment at 50 and 200 mg/kg/day (about 10 and 40 times the recommended human dose on a body surface area basis) produced benign squamous cell papillomas and malignant squamous cell carcinomas. Rare gastrointestinal tumors associated with pantoprazole treatment included an adenocarcinoma of the duodenum at 50 mg/kg/day, and benign polyps and adenocarcinomas of the gastric fundus at 200 mg/kg/day. In the liver, treatment at 0.5-200 mg/kg/day produced dose-related increases in the incidences of hepatocellular adenomas and carcinomas. In the thyroid gland, treatment at 200 mg/kg/day produced increased incidences of follicular cell adenomas and carcinomas for both male and female rats. Sporadic occurrences of hepatocellular adenomas and a hepatocellular carcinoma were observed in Sprague-Dawley rats exposed to pantoprazole in 6-month and 12-month toxicity studies. In a 24-month carcinogenicity study, Fischer 344 rats were treated orally with doses of 5-50 mg/kg/day, approximately 1-10 times the recommended human dose based on body surface area. In the gastric fundus, treatment at 5-50 mg/kg/day produced enterochromaffin-like (ECL) cell hyperplasia and benign and malignant neuroendocrine cell tumors. Dose selection for this study may not have been adequate to comprehensively evaluate the carcinogenic potential of pantoprazole. In a 24-month carcinogenicity study, B6C3F1 mice were treated orally with doses of 5-150 mg/kg/day, 0.5-15 times the recommended human dose based on body surface area. In the liver, treatment at 150 mg/kg/day produced increased incidences of combined hepatocellular adenomas and carcinomas in female mice. Treatment at 5-150 mg/kg/day also produced gastric fundic ECL cell hyperplasia. Pantoprazole was positive in the in vitro human lymphocyte chromosomal aberration assays, in one of two mouse micronucleus tests for clastogenic effects, and in the in vitro Chinese hamster ovarian cell/HGPRT forward mutation assay for mutagenic effects. Equivocal results were observed in the in vivo rat liver DNA covalent binding assay. Pantoprazole was negative in the in vitro Ames mutation assay, the in vitro unscheduled DNA synthesis (UDS) assay with rat hepatocytes, the in vitro AS52/GPT mammalian cell-forward gene mutation assay, the in vitro thymidine kinase mutation test with mouse lymphoma L5178Y cells, and the in vivo rat bone marrow cell chromosomal aberration assay. Pantoprazole at oral doses up to 500 mg/kg/day in male rats (98 times the recommended human dose based on body surface area) and 450 mg/kg/day in female rats (88 times the recommended human dose based on body surface area) was found to have no effect on fertility and reproductive performance. Pregnancy, Teratogenic Effects, Pregnancy Category B Teratology studies have been performed in rats at oral doses up to 450 mg/kg/day (88 times the recommended human dose based on body surface area) and rabbits at oral doses up to 40 mg/kg/day (16 times the recommended human dose based on body surface area) and have revealed no evidence of impaired fertility or harm to the fetus due to pantoprazole. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Nursing Mothers Pantoprazole and its metabolites are excreted in the milk of rats. It is not known whether pantoprazole is excreted in human milk. Many drugs which are excreted in human milk have a potential for serious adverse reactions in nursing infants. Based on the potential for tumorigenicity shown for pantoprazole in rodent carcinogenicity studies, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the benefit of the drug to the mother. Pediatric Use Safety and effectiveness in pediatric patients have not been established. Use in Women Erosive esophagitis healing rates in the 221 women treated with pantoprazole in US clinical trials were similar to those found in men. The incidence rates of adverse events were also similar between men and women. Geriatric Use Erosive esophagitis healing rates in the 107 elderly patients (65 years old) treated with pantoprazole in US clinical trials were similar to those found in patients under the age of 65. The incidence rates of adverse events and laboratory abnormalities in patients aged 65 years and older were similar to those associated with patients younger than 65 years of age. The healing rates of the 25 patients at least 75 years old were 80% for those treated with 10 mg of pantoprazole and 100% for those patients treated with either 20 or 40 mg. In addition, the safety profile in patients 65 years and older was similar to that of patients younger than 65 years of age. DRUG INTERACTIONS: Pantoprazole is metabolized through the cytochrome P450 system, primarily the CYP2C19 and CYP3A4 isozymes, and subsequently undergoes Phase II conjugation. Based on studies evaluating possible interactions of pantoprazole with other drugs metabolized by the cytochrome P450 system, no dosage adjustment is needed with concomitant use of the following drugs: theophylline, cisapride, antipyrine, caffeine, carbamazepine, diazepam, diclofenac, digoxin, ethanol, glyburide, an oral contraceptive (levonorgestrel/ethinyl estradiol), metoprolol, nifedipine, phenytoin, or warfarin. Clinically relevant interactions of pantoprazole with other drugs with the same metabolic pathways are not expected. Therefore, when co-administered with pantoprazole, adjustment of the dosage of pantoprazole or of such drugs may not be necessary. There was also no interaction with concomitantly administered antacids. Because of profound and long lasting inhibition of gastric acid secretion, it is theoretically possible that pantoprazole may interfere with absorption of drugs where gastric pH is an important determinant of their bioavailability (e.g., ketoconazole, ampicillin esters, and iron salts). ADVERSE REACTIONS: Worldwide, more than 11,100 patients have been treated with pantoprazole in clinical trials involving various dosages and duration of treatment. In general, pantoprazole has been well tolerated in both short-term and long-term trials. In two US controlled clinical trials involving pantoprazole sodium 10, 20, or 40 mg doses for up to 8 weeks, there were no dose-related effects on the incidence of adverse events. The adverse events shown in TABLE 4 considered by investigators to be possibly, probably or definitely related to drug occurred in 1% or more in the individual studies of GERD patients on therapy with pantoprazole sodium. Headache Diarrhea Flatulence Abdominal pain Rash Eructation Insomnia Hyperglycemia In addition, in these short-term domestic trials, the following treatment-emergent events, regardless of causality, occurred at a rate of 1% in pantoprazole sodium-treated patients: asthenia, back pain, chest pain, neck pain, flu syndrome, infection, pain, migraine, constipation, dyspepsia, gastroenteritis, gastrointestinal disorder, nausea, rectal disorder, vomiting, hyperlipemia, liver function tests abnormal, SGPT increased, arthralgia, anxiety, dizziness, hypertonia, bronchitis, cough increased, dyspnea, pharyngitis, rhinitis, sinusitis, upper respiratory tract infection, urinary frequency, and urinary tract infection. In international short-term double-blind or open-label, clinical trials involving 20-80 mg per day, the adverse events shown in TABLE 5 were reported to occur in 1% or more of 2805 GERD patients receiving pantoprazole for up to 8 weeks. Headache Diarrhea Abdominal Pain Additional adverse experiences occurring in <1% of GERD patients based on pooled results from either short-term domestic or international trials are shown below within each body system. In most instances the relationship to pantoprazole was unclear. Body as a Whole: Abscess, allergic reaction, chills, cyst, face edema, fever, generalized edema, heat stroke, hernia, laboratory test abnormal, malaise, moniliasis, neoplasm, non-specified drug reaction. Cardiovascular System: Aangina pectoris, arrhythmia, cardiovascular disorder, chest pain substernal, congestive heart failure, electrocardiogram abnormal, haemorrhage, hypertension, hypotension, myocardial ischemia, palpitation, retinal vascular disorder, syncope, tachycardia, thrombophlebitis, thrombosis, vasodilatation. Digestive System: Anorexia, aphthous stomatitis, cardiospasm, colitis, dry mouth, duodenitis, dysphagia, enteritis, esophageal hemorrhage, esophagitis, gastrointestinal carcinoma, gastrointestinal hemorrhage, gastrointestinal moniliasis, gingivitis, glossitis, halitosis, hematemesis, increased appetite, melena, mouth ulceration, oral moniliasis, periodontal abscess, periodontitis, rectal hemorrhage, stomach ulcer, stomatitis, stools abnormal, tongue discoloration, ulcerative colitis. Endocrine System: Diabetes mellitus, glycosuria, goiter. Hepato-biliary System: Biliary pain, bilirubinemia, cholecystitis, cholelithiasis, cholestatic jaundice, hepatitis, alkaline phosphatase increased, gamma glutamyl transpeptidase increased, SGOT increased. Hemic and Lymphatic System: Anemia, ecchymosis, eosinophilia, hypochromic anemia, iron deficiency anemia, leukocytosis, leukopenia, thrombocytopenia. Metabolic and Nutritional: Dehydration, edema, gout, peripheral edema, thirst, weight gain, weight loss. Musculoskeletal System: Arthritis, arthrosis, bone disorder, bone pain, bursitis, joint disorder, leg cramps, neck rigidity, myalgia, tenosynovitis. Nervous System: Abnormal dreams, confusion, convulsion, depression, dry mouth, dysarthria, emotional lability, hallucinations, hyperkinesia, hypesthesia, libido decreased, nervousness, neuralgia, neuritis, paresthesia, reflexes decreased, sleep disorder, somnolence, thinking abnormal, tremor, vertigo. Respiratory System: Asthma, epistaxis, hiccup, laryngitis, lung disorder, pneumonia, voice alteration. Skin and Appendages: Acne, alopecia, contact dermatitis, dry skin, eczema, fungal dermatitis, hemorrhage, herpes simplex, herpes zoster, lichenoid dermatitis, maculopapular rash, pain, pruritus, skin disorder, skin ulcer, sweating, urticaria. Special Senses: Abnormal vision, amblyopia, cataract specified, deafness, diplopia, ear pain, extraocular palsy, glaucoma, otitis externa, taste perversion, tinnitus. Urogenital System: Albuminuria, balanitis, breast pain, cystitis, dysmenorrhea, dysuria, epididymitis, hematuria, impotence, kidney calculus, kidney pain, nocturia, prostatic disorder, pyelonephritis, scrotal edema, urethral pain, urethritis, urinary tract disorder, urination impaired, vaginitis. Postmarketing Reports: There have been spontaneous reports of adverse events with the post-marketing use of pantoprazole. These reports include anaphylaxis; angioedema (Quincke's edema); anterior ischemic optic neuropathy; severe dematologic reactions, including erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis (TEN, some fatal); and pancreatitis. In addition, also observed have been jaundice, confusion, hypokinesia, speech disorder, increased salivation, vertigo, nausea, and tinnitus. Laboratory Values: In two US controlled trials, 0.4% of the patients on 40 mg pantoprazole experienced SGPT elevations of greater than 3 times the upper limit of normal at the final treatment visit. Except in those patients where there was a clear alternative explanation for a laboratory value change, such as intercurrent illness, the elevations tended to be mild and sporadic. The following changes in laboratory parameters were reported as adverse events: creatinine increased, hypercholesterolemia, and hyperuricemia. OVERDOSAGE: Some reports of overdosage with pantoprazole have been received. A spontaneous report of a suicide involving an overdosage of pantoprazole (560 mg) has been received; however, the death was more reasonably attributed to the unknown doses of chloroquine and zopiclone which were also taken since two other reported cases of pantoprazole overdosage involved similar amounts of pantoprazole (400 and 600 mg) with no adverse effects observed. One patient in a flexible dosing study of refractory peptic ulcer disease received a dose of 320 mg per day for 3 months; treatment was well tolerated. Doses of up to 240 mg per day, given intravenously for 7 days, have been administered to healthy subjects and have been well tolerated. Pantoprazole is not removed by hemodialysis. Single oral doses of pantoprazole at 709 mg/kg, 798 mg/kg, and 887 mg/kg were lethal to mice, rats, and dogs, respectively. The symptoms of acute toxicity were hypoactivity, ataxia, hunched sitting, limb-splay, lateral position, segregation, absence of ear reflex, and tremor. DOSAGE AND ADMINISTRATION: Treatment of Erosive Esophagitis: The recommended adult oral dose is 40 mg given once daily for up to 8 weeks. For those patients who have not healed after 8 weeks of treatment, an additional 8-week course of pantoprazole sodium may be considered. (See INDICATIONS AND USAGE.) No dosage adjustment is necessary in patients with mild, moderate or severe renal insufficiency or in elderly patients. No dosage adjustment is necessary in patients undergoing hemodialysis. No dosage adjustment is needed in patients with mild or moderate hepatic impairment. The pharmacokinetics of pantoprazole have not yet been well characterized in patients with severe hepatic impairment. Therefore, the potential for modest drug accumulation ( 21%) when dosed once daily needs to be weighed against the potential for reduced acid control when dosed every other day in these patients. Pantoprazole sodium delayed-release tablets should be swallowed whole, with or without food in the stomach. Concomitant administration of antacids does not affect the absorption of pantoprazole sodium.

Domperidone

DOMPERIDONE ACTS BY BLOCKING THE DOPAMINE RECEPTORS IN BRAIN. IT STIMULATES GASTRIC MOTILITY WITHOUT AFFECTING GASTRIC, BILIARY OR PANCREATIC SECRETION AND INCREASES GASTRIC PERISTALSIS, LEADING TO ACCELERATED GASTRIC EMPTYING.

Dose

ADULT - 20-40 MG 3-4 TIMES CHILDREN - 0.3 MG/KG 3-4 TIMES

Monograph

Domperidone Domperidone (Ph. Eur.) is a white or almost white powder. Practically insoluble in water, slightly soluble in alcohol and methyl alcohol: soluble in dimethylformamide. Protect from light. Domperidone Maleate (Ph. Eur.) is a white or almost white powder; its exhibits polymorphism. Very slightly soluble in water and in alcohol: sparingly soluble in dimethylforma- mide; slightly soluble in methyl alcohol. Protect from light. Adverse Effects Domperidone does not readily cross the blood-brain barrier and the incidence of central effects such as extrapyramidal reactions or drowsiness may be low- er than with metoclopramide; however, there have been reports of dystonic reactions. Plas- ma-prolactin concentrations may also be increased which may lead to galactorrhoea or gynaecomastia. Domperidone by injection has been associated with convulsions, arrhythmias, and cardiac arrest. Fatali- ties have restricted administration by this route. Effects on the cardiovascular system. Sudden death has occurred in cancer patients given domperidone intravenously in high doses. Four cancer patients experienced cardiac ar- rest following high intravenous doses and 2 of 4 similar pa- tients experienced ventricular arrhythmias. Following such reports the manufacturers withdrew the injection from gener- al use in the UK. Effects on the endocrine system. Reports of galactor- rhoea with gynaecomastia or mastalgia generally associat- ed with raised serum-prolactin concentrations. Gynaecomastia without galactorrhoea has also been reported. Extrapyramidal effects. Reports of extrapyramidal symp- toms. including acute dystonic reactions, in individual pa- tients given domperidone. Precautions Due to similarities in the mode of action, the precau- tions described under Metoclopramide Hydrochlo- ride should be observed. General In one study in hypertensive patients, intravenously administered was shown to release catecholamines; hence, caution should be exercised when domperidone is used in patients with hypertension. Intravenous injections of undiluted metoclopramide should be made slowly allowing 1 to 2 minutes for 10 mg since a transient but intense feeling of anxiety and restlessness, followed by drowsiness, may occur with rapid administration. Domperidone should be used with great caution if given intravenously, because of the risk of arrhythmias, especial- ly in patients predisposed to cardiac arrhythmias or hypokalaemia. Pharmacokinetics The systemic bioavailability of domperidone is only about 15% in fasting subjects given a dose by mouth, although this is increased when domperi- done is given after food. The low bioavailability is thought to be due to first-pass hepatic and intestinal metabolism. The bioavailability of rectal domperi- done is similar to that following oral administration, although peak plasma concentrations are only achieved after about an hour, compared with 30 minutes after a dose by mouth. Domperidone is more than 90% bound to plasma protein, and has a terminal elimination half-life of about 7.5 hours. It is chiefly cleared from the blood by extensive metabolism. About 30% of an oral dose is excreted in urine within 24 hours, almost entirely as metabolites; the remainder of a dose is excreted in faeces over several days. about 10% as unchanged drug. It does not readily cross the blood-brain barri- er. Small amounts of domperidone are distributed into breast milk. reaching concentrations about one- quarter of those in maternal serum. References. Uses and Administration Domperidone is a dopamine antagonist with actions and uses similar to those of metoclopramide. It is used as an antiemetic for the short term treatment of nausea and vomiting of various aetiologies , including that associated with cancer therapy, and nausea and vomiting associated with levodopa or bromocriptine therapy for parkin- sonism. It is not considered suitable for chronic nausea, and vomiting, nor for the routine prophylaxis of postoperative vomiting. Domperidone is also used for its prokinetic actions in disorders of gastro-intestinal motility such as diabetic gastroparesis and has been tried in other gastro-intestinal disorders. Domperidone is used as the maleate in tablet prepa- rations, but doses are expressed in terms of the base. It is administered in doses of 10 to 20 mg by mouth or 30 to 60 mg rectally every 4 to 8 hours. In the treatment of nausea and vomiting in parkinsonian patients, therapy may be continued for a maximum of 12 weeks. In children doses of 200 to 400 ng per kg body-weight may be given by mouth every 4 to 8 hours; approximately 2 to 4 mg per kg daily may be given rectally. Domperidone has been administered parenterally, but such administration has been associated with se- vere adverse effects (see above). Parkinsonism : Domperidone is used to control gastro-intes- tinal effects of dopaminergic drugs in the management of par- kinsonism . It may be of use in those patients who experience peripheral effects with levodopa despite the use of peripheral decarboxylase inhibitors and for patients using dopamine agonists such as bromocriptine or apomorphine since peripheral decarboxylase inhibitors are ineffective for preventing the peripheral effects of these drugs. Although domperidone does not readily cross the blood brain barrier there have been isolated reports of extrapyramidal effects as- sociated with its use (see above). Consequently there has been concern over its potential to produce central effects and some consider that domperidone should only be used in patients with parkinsonism when safer antiemetic measures have failed , However this view has been contested both by the manufacturers and other workers. In a subsequent review of the use of domperidone in Parkinson's disease Parkes con- sidered that domperidone might produce central blockade of the therapeutic effects of levodopa if given at a high oral dos- age such as 120 mg daily for prolonged periods but also noted that such high doses were rarely required to control levodopa- induced vomiting. In the UK. domperidone is limited to a maximum of 12 weeks treatment in nausea and vomiting in- duced by antiparkinsonian treatment.