Dosage Form: tablet, delayed release; granule, delayed release
FULL PRESCRIBING INFORMATION
Indications and Usage for Protonix Tablets
PROTONIX For Delayed-Release Oral Suspension and PROTONIX Delayed-Release Tablets are indicated for:
Short-Term Treatment of Erosive Esophagitis Associated With Gastroesophageal Reflux Disease (GERD)
PROTONIX is indicated in adults and pediatric patients five years of age and older for the short-term treatment (up to 8 weeks) in the healing and symptomatic relief of erosive esophagitis. For those adult patients who have not healed after 8 weeks of treatment, an additional 8-week course of PROTONIX may be considered. Safety of treatment beyond 8 weeks in pediatric patients has not been established.
Maintenance of Healing of Erosive Esophagitis
PROTONIX is indicated for maintenance of healing of erosive esophagitis and reduction in relapse rates of daytime and nighttime heartburn symptoms in adult patients with GERD. Controlled studies did not extend beyond 12 months.
Pathological Hypersecretory Conditions Including Zollinger-Ellison Syndrome
PROTONIX is indicated for the long-term treatment of pathological hypersecretory conditions, including Zollinger-Ellison syndrome.
Protonix Tablets Dosage and Administration
Recommended Dosing Schedule
PROTONIX is supplied as delayed-release granules in packets for preparation of oral suspensions or as delayed-release tablets. The recommended dosages are outlined in Table 1.
Administration Instructions
Directions for method of administration for each dosage form are presented in Table 2.
Formulation | Route | Instructions* |
|---|---|---|
| * Patients should be cautioned that PROTONIX Delayed-Release Tablets and PROTONIX For Delayed-Release Oral Suspension should not be split, chewed, or crushed. | ||
| Delayed-Release Tablets | Oral | Swallowed whole, with or without food |
| For Delayed-Release Oral Suspension | Oral | Administered in 1 teaspoonful of applesauce or apple juice approximately 30 minutes prior to a meal |
| For Delayed-Release Oral Suspension | Nasogastric tube | See instructions below |
PROTONIX Delayed-Release Tablets should be swallowed whole, with or without food in the stomach. If patients are unable to swallow a 40 mg tablet, two 20 mg tablets may be taken. Concomitant administration of antacids does not affect the absorption of PROTONIX Delayed‑Release Tablets.
PROTONIX For Delayed-Release Oral Suspension
PROTONIX For Delayed-Release Oral Suspension should only be administered approximately 30 minutes prior to a meal via oral administration in apple juice or applesauce or nasogastric tube in apple juice only. Because proper pH is necessary for stability, do not administer PROTONIX For Delayed-Release Oral Suspension in liquids other than apple juice, or foods other than applesauce.
Do not divide the 40 mg PROTONIX For Delayed-Release Oral Suspension packet to create a 20 mg dosage for pediatric patients who are unable to take the tablet formulation.
PROTONIX For Delayed-Release Oral Suspension - Oral Administration in Applesauce
- Open packet.
- Sprinkle granules on one teaspoonful of applesauce. DO NOT USE OTHER FOODS OR CRUSH OR CHEW THE GRANULES.
- Take within 10 minutes of preparation.
- Take sips of water to make sure granules are washed down into the stomach. Repeat water sips as necessary.
- Open packet.
- Empty granules into a small cup or teaspoon containing one teaspoon of apple juice.
- Stir for 5 seconds (granules will not dissolve) and swallow immediately.
- To make sure that the entire dose is taken, rinse the container once or twice with apple juice to remove any remaining granules. Swallow immediately.
For patients who have a nasogastric tube or gastrostomy tube in place, PROTONIX For Delayed‑Release Oral Suspension can be given as follows:
- Remove the plunger from the barrel of a 2 ounce (60 mL) catheter-tip syringe. Discard the plunger.
- Connect the catheter tip of the syringe to a 16 French (or larger) tube.
- Hold the syringe attached to the tubing as high as possible while giving PROTONIX For Delayed-Release Oral Suspension to prevent any bending of the tubing.
- Empty the contents of the packet into the barrel of the syringe.
- Add 10 mL (2 teaspoonfuls) of apple juice and gently tap and/or shake the barrel of the syringe to help rinse the syringe and tube. Repeat at least twice more using the same amount of apple juice (10 mL or 2 teaspoonfuls) each time. No granules should remain in the syringe.
Dosage Forms and Strengths
- 40 mg, yellow oval biconvex tablets imprinted with PROTONIX (brown ink) on one side
- 20 mg, yellow oval biconvex tablets imprinted with P20 (brown ink) on one side
For Delayed-Release Oral Suspension:
- 40 mg, pale yellowish to dark brownish, enteric-coated granules in a unit dose packet
Contraindications
PROTONIX is contraindicated in patients with known hypersensitivity to any component of the formulation [see Description (11)] or any substituted benzimidazole.
Warnings and Precautions
Concurrent Gastric Malignancy
Symptomatic response to therapy with PROTONIX does not preclude the presence of gastric malignancy.
Atrophic Gastritis
Atrophic gastritis has been noted occasionally in gastric corpus biopsies from patients treated long-term with PROTONIX, particularly in patients who were H. pylori positive.
Cyanocobalamin (Vitamin B-12) Deficiency
Generally, 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.
Bone Fracture
Several published observational studies suggest that proton pump inhibitor (PPI) therapy may be associated with an increased risk for osteoporosis-related fractures of the hip, wrist, or spine. The risk of fracture was increased in patients who received high-dose, defined as multiple daily doses, and long-term PPI therapy (a year or longer). Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated. Patients at risk for osteoporosis-related fractures should be managed according to established treatment guidelines [see Dosage and Administration (2) and Adverse Reactions (6.2)].
Hypomagnesemia
Hypomagnesemia, symptomatic and asymptomatic, has been reported rarely in patients treated with PPIs for at least three months, in most cases after a year of therapy. Serious adverse events include tetany, arrhythmias, and seizures. In most patients, treatment of hypomagnesemia required magnesium replacement and discontinuation of the PPI.
For patients expected to be on prolonged treatment or who take PPIs with medications such as digoxin or drugs that may cause hypomagnesemia (e.g., diuretics), health care professionals may consider monitoring magnesium levels prior to initiation of PPI treatment and periodically. [See Adverse Reactions 6.2)]
Tumorigenicity
Due to the chronic nature of GERD, there may be a potential for prolonged administration of PROTONIX. In long-term rodent studies, pantoprazole was carcinogenic and caused rare types of gastrointestinal tumors. The relevance of these findings to tumor development in humans is unknown [see Nonclinical Toxicology (13.1)].
Interference with Urine Screen for THC
Adverse Reactions
The adverse reaction profiles for PROTONIX (pantoprazole sodium) For Delayed-Release Oral Suspension and PROTONIX (pantoprazole sodium) Delayed-Release Tablets are similar.
Clinical Trial Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
Adults
Safety in nine randomized comparative US clinical trials in patients with GERD included 1,473 patients on oral PROTONIX (20 mg or 40 mg), 299 patients on an H2-receptor antagonist, 46 patients on another proton pump inhibitor, and 82 patients on placebo. The most frequently occurring adverse reactions are listed in Table 3.
| PROTONIX (n=1473) % | Comparators (n=345) % | Placebo (n=82) % | |
|---|---|---|---|
| Headache | 12.2 | 12.8 | 8.5 |
| Diarrhea | 8.8 | 9.6 | 4.9 |
| Nausea | 7.0 | 5.2 | 9.8 |
| Abdominal pain | 6.2 | 4.1 | 6.1 |
| Vomiting | 4.3 | 3.5 | 2.4 |
| Flatulence | 3.9 | 2.9 | 3.7 |
| Dizziness | 3.0 | 2.9 | 1.2 |
| Arthralgia | 2.8 | 1.4 | 1.2 |
Additional adverse reactions that were reported for PROTONIX in clinical trials with a frequency of ≤ 2% are listed below by body system:
Body as a Whole: allergic reaction, pyrexia, photosensitivity reaction, facial edema
Gastrointestinal: constipation, dry mouth, hepatitis
Hematologic: leukopenia, thrombocytopenia
Metabolic/Nutritional: elevated CK (creatine kinase), generalized edema, elevated triglycerides, liver enzymes elevated
Skin and Appendages: urticaria, rash, pruritus
Special Senses: blurred vision
Pediatric Patients
Safety of PROTONIX in the treatment of Erosive Esophagitis (EE) associated with GERD was evaluated in pediatric patients ages 1 year through 16 years in three clinical trials. Safety trials involved pediatric patients with EE; however, as EE is uncommon in the pediatric population, 249 pediatric patients with endoscopically-proven or symptomatic GERD were also evaluated. All adult adverse reactions to PROTONIX are considered relevant to pediatric patients. In patients ages 1 year through 16 years, the most commonly reported (> 4%) adverse reactions include: URI, headache, fever, diarrhea, vomiting, rash, and abdominal pain.
For safety information in patients less than 1 year of age see Use in Specific Populations (8.4).
Additional adverse reactions that were reported for PROTONIX in pediatric patients in clinical trials with a frequency of ≤ 4% are listed below by body system:
Body as a Whole: allergic reaction, facial edema
Gastrointestinal: constipation, flatulence, nausea
Metabolic/Nutritional: elevated triglycerides, elevated liver enzymes, elevated CK (creatine kinase)
Musculoskeletal: arthralgia, myalgia
Skin and Appendages: urticaria
The following adverse reactions seen in adults in clinical trials were not reported in pediatric patients in clinical trials, but are considered relevant to pediatric patients: photosensitivity reaction, dry mouth, hepatitis, thrombocytopenia, generalized edema, depression, pruritus, leukopenia, and blurred vision.
Zollinger-Ellison Syndrome
In clinical studies of Zollinger-Ellison Syndrome, adverse reactions reported in 35 patients taking PROTONIX 80 mg/day to 240 mg/day for up to 2 years were similar to those reported in adult patients with GERD.
Postmarketing Experience
The following adverse reactions have been identified during postapproval use of PROTONIX. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
These adverse reactions are listed below by body system:
General Disorders and Administration Conditions: asthenia, fatigue, malaise
Hepatobiliary Disorders: hepatocellular damage leading to jaundice and hepatic failure
Immune System Disorders: anaphylaxis (including anaphylactic shock)
Investigations: weight changes
Metabolism and Nutritional Disorders: hyponatremia, hypomagnesemia
Musculoskeletal Disorders: rhabdomyolysis, bone fracture
Psychiatric Disorders: hallucination, confusion, insomnia, somnolence
Renal and Urinary Disorders: interstitial nephritis
Skin and Subcutaneous Tissue Disorders: severe dermatologic reactions (some fatal), including erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis (TEN, some fatal), and angioedema (Quincke's edema)
Drug Interactions
Interference with Antiretroviral Therapy
Concomitant use of atazanavir or nelfinavir with proton pump inhibitors is not recommended. Coadministration of atazanavir or nelfinavir with proton pump inhibitors is expected to substantially decrease atazanavir or nelfinavir plasma concentrations and may result in a loss of therapeutic effect and development of drug resistance.
Coumarin Anticoagulants
There have been postmarketing reports of increased INR and prothrombin time in patients receiving proton pump inhibitors, including PROTONIX, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death. Patients treated with proton pump inhibitors and warfarin concomitantly should be monitored for increases in INR and prothrombin time.
Clopidogrel
Concomitant administration of pantoprazole and clopidogrel in healthy subjects had no clinically important effect on exposure to the active metabolite of clopidogrel or clopidogrel-induced platelet inhibition [see Clinical Pharmacology (12.3)]. No dose adjustment of clopidogrel is necessary when administered with an approved dose of Protonix.
Drugs for Which Gastric pH Can Affect Bioavailability
Pantoprazole causes long-lasting inhibition of gastric acid secretion. Therefore, 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).
False Positive Urine Tests for THC
There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving proton pump inhibitors. An alternative confirmatory method should be considered to verify positive results.
USE IN SPECIFIC POPULATIONS
Pregnancy
Teratogenic Effects
Pregnancy Category B
Reproduction studies have been performed in rats at oral doses up to 88 times the recommended human dose and in rabbits at oral doses up to 16 times the recommended human dose 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 [see Nonclinical Toxicology (13.2)].
Nursing Mothers
Pantoprazole and its metabolites are excreted in the milk of rats. Pantoprazole excretion in human milk has been detected in a study of a single nursing mother after a single 40 mg oral dose. The clinical relevance of this finding is not known. 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
The safety and effectiveness of PROTONIX for short‑term treatment (up to eight weeks) of erosive esophagitis (EE) associated with GERD have been established in pediatric patients 1 year through 16 years of age. Effectiveness for EE has not been demonstrated in patients less than 1 year of age. In addition, for patients less than 5 years of age, there is no appropriate dosage strength in an age-appropriate formulation available. Therefore, PROTONIX is indicated for the short-term treatment of EE associated with GERD for patients 5 years and older. The safety and effectiveness of PROTONIX for pediatric uses other than EE have not been established.
1 year through 16 years of age
Use of PROTONIX in pediatric patients 1 year through 16 years of age for short-term treatment (up to eight weeks) of EE associated with GERD is supported by: a) extrapolation of results from adequate and well-controlled studies that supported the approval of PROTONIX for treatment of EE associated with GERD in adults, and b) safety, effectiveness, and pharmacokinetic studies performed in pediatric patients [see Clinical Studies (14.1), and Clinical Pharmacology (12.3)].
Safety of PROTONIX in the treatment of EE associated with GERD in pediatric patients 1 through 16 years of age was evaluated in three multicenter, randomized, double-blind, parallel-treatment studies, involving 249 pediatric patients, including 8 with EE (4 patients ages 1 year to 5 years and 4 patients 5 years to 11 years). The children ages 1 year to 5 years with endoscopically diagnosed EE (defined as an endoscopic Hetzel-Dent score ≥ 2) were treated once daily for 8 weeks with one of two dose levels of PROTONIX (approximating 0.6 mg/kg or 1.2 mg/kg). All 4 of these patients with EE were healed (Hetzel‑Dent score of 0 or 1) at 8 weeks. Because EE is uncommon in the pediatric population, predominantly pediatric patients with endoscopically-proven or symptomatic GERD were also included in these studies. Patients were treated with a range of doses of PROTONIX once daily for 8 weeks. For safety findings see Adverse Reactions (6.1). Because these pediatric trials had no placebo, active comparator, or evidence of a dose response, the trials were inconclusive regarding the clinical benefit of PROTONIX for symptomatic GERD in the pediatric population. The effectiveness of PROTONIX for treating symptomatic GERD in pediatric patients has not been established.
Although the data from the clinical trials support use of PROTONIX for the short-term treatment of EE associated with GERD in pediatric patients 1 year through 5 years, there is no commercially available dosage formulation appropriate for patients less than 5 years of age [see Dosage and Administration (2)].
In a population pharmacokinetic analysis, clearance values in the children 1 to 5 years old with endoscopically proven GERD had a median value of 2.4 L/h. Following a 1.2 mg/kg equivalent dose (15 mg for ≤ 12.5 kg and 20 mg for > 12.5 to < 25 kg), the plasma concentrations of pantoprazole were highly variable and the median time to peak plasma concentration was 3 to 6 hours. The estimated AUC for patients 1 to 5 years old was 37% higher than for adults receiving a single 40 mg tablet, with a geometric mean AUC value of 6.8 µg•hr/mL.
Neonates to less than one year of age
PROTONIX was not found to be effective in a multicenter, randomized, double-blind, placebo‑controlled, treatment-withdrawal study of 129 pediatric patients 1 through 11 months of age. Patients were enrolled if they had symptomatic GERD based on medical history and had not responded to non-pharmacologic interventions for GERD for two weeks. Patients received PROTONIX daily for four weeks in an open-label phase, then patients were randomized in equal proportion to receive PROTONIX treatment or placebo for the subsequent four weeks in a double-blind manner. Efficacy was assessed by observing the time from randomization to study discontinuation due to symptom worsening during the four-week treatment-withdrawal phase. There was no statistically significant difference between PROTONIX and placebo in the rate of discontinuation.
In this trial, the adverse reactions that were reported more commonly (difference of ≥ 4%) in the treated population compared to the placebo population were elevated CK, otitis media, rhinitis, and laryngitis.
In a population pharmacokinetic analysis, the systemic exposure was higher in patients less than 1 year of age with GERD compared to adults who received a single 40 mg dose (geometric mean AUC was 103% higher in preterm infants and neonates receiving single dose of 2.5 mg of PROTONIX, and 23% higher in infants 1 through 11 months of age receiving a single dose of approximately 1.2 mg/kg). In these patients, the apparent clearance (CL/F) increased with age (median clearance: 0.6 L/hr, range: 0.03 to 3.2 L/hr).
These doses resulted in pharmacodynamic effects on gastric but not esophageal pH. Following once daily dosing of 2.5 mg of PROTONIX in preterm infants and neonates, there was an increase in the mean gastric pH (from 4.3 at baseline to 5.2 at steady-state) and in the mean % time that gastric pH was > 4 (from 60% at baseline to 80% at steady-state). Following once daily dosing of approximately 1.2 mg/kg of PROTONIX in infants 1 through 11 months of age, there was an increase in the mean gastric pH (from 3.1 at baseline to 4.2 at steady-state) and in the mean % time that gastric pH was > 4 (from 32% at baseline to 60% at steady-state). However, no significant changes were observed in mean intraesophageal pH or % time that esophageal pH was < 4 in either age group.
Because PROTONIX was not shown to be effective in the randomized, placebo-controlled study in this age group, the use of PROTONIX for treatment of symptomatic GERD in infants less than 1 year of age is not indicated.
Geriatric Use
In short-term US clinical trials, erosive esophagitis healing rates in the 107 elderly patients (≥ 65 years old) treated with PROTONIX were similar to those found in patients under the age of 65. The incidence rates of adverse reactions and laboratory abnormalities in patients aged 65 years and older were similar to those associated with patients younger than 65 years of age.
Gender
Erosive esophagitis healing rates in the 221 women treated with PROTONIX Delayed-Release Tablets in US clinical trials were similar to those found in men. In the 122 women treated long‑term with PROTONIX 40 mg or 20 mg, healing was maintained at a rate similar to that in men. The incidence rates of adverse reactions were also similar for men and women.
Patients with Hepatic Impairment
Doses higher than 40 mg/day have not been studied in patients with hepatic impairment [see Clinical Pharmacology (12.3)].
Overdosage
Experience in patients taking very high doses of PROTONIX (> 240 mg) is limited. Spontaneous post-marketing reports of overdose are generally within the known safety profile of PROTONIX.
Pantoprazole is not removed by hemodialysis. In case of overdosage, treatment should be symptomatic and supportive.
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.
Protonix Tablets Description
The active ingredient in PROTONIX (pantoprazole sodium) For Delayed-Release Oral Suspension and PROTONIX (pantoprazole sodium) Delayed-Release Tablets 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 C16H14F2N3NaO4S x 1.5 H2O, with a molecular weight of 432.4. The structural formula is:
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 and approximately 220 hours at pH 7.8.
PROTONIX (pantoprazole sodium) is supplied as a for delayed-release oral suspension, available in one strength (40 mg), and as a delayed-release tablet, available in two strengths (20 mg and 40 mg).
Each PROTONIX (pantoprazole sodium) Delayed-Release Tablet contains 45.1 mg or 22.56 mg of pantoprazole sodium sesquihydrate (equivalent to 40 mg or 20 mg pantoprazole, respectively) with the following inactive ingredients: calcium stearate, crospovidone, hypromellose, iron oxide, mannitol, methacrylic acid copolymer, polysorbate 80, povidone, propylene glycol, sodium carbonate, sodium lauryl sulfate, titanium dioxide, and triethyl citrate. PROTONIX Delayed-Release Tablets (40 mg and 20 mg) complies with USP dissolution test 2.
PROTONIX (pantoprazole sodium) For Delayed-Release Oral Suspension, 40 mg, contains the active ingredient pantoprazole sodium sesquihydrate in the form of enteric‑coated granules in unit dose packets. Each unit dose packet contains enteric-coated granules containing 45.1 mg pantoprazole sodium sesquihydrate (equivalent to 40 mg of pantoprazole) with the following inactive ingredients: crospovidone, hypromellose, methacrylic acid copolymer, microcrystalline cellulose, polysorbate 80, povidone, sodium carbonate, sodium lauryl sulfate, talc, titanium dioxide, triethyl citrate, and yellow ferric oxide.
Protonix Tablets - Clinical Pharmacology
Mechanism of Action
Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production by covalently binding to the (H+, K+)-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect 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 for all doses tested (20 mg to 120 mg).
Pharmacodynamics
PROTONIX (pantoprazole sodium) For Delayed-Release Oral Suspension, 40 mg has been shown to be comparable to PROTONIX (pantoprazole sodium) Delayed-Release Tablets in suppressing pentagastrin-stimulated MAO in patients (n = 49) with GERD and a history of EE. In this multicenter, pharmacodynamic crossover study, a 40 mg oral dose of PROTONIX For Delayed-Release Oral Suspension administered in a teaspoonful of applesauce was compared with a 40 mg oral dose of PROTONIX Delayed-Release Tablets after administration of each formulation once daily for 7 days. Both medications were administered thirty minutes before breakfast. Pentagastrin-stimulated (MAO) was assessed from hour 23 to 24 at steady state.
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 to 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 significantly greater increases in gastric pH 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. The effects of pantoprazole on median pH from one double-blind crossover study are shown in Table 4.
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 PROTONIX 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. Median serum gastrin levels remained within normal limits during maintenance therapy with PROTONIX Delayed-Release Tablets.
In long-term international studies involving over 800 patients, a 2- to 3-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 to 3 times baseline for up to 4 years of periodic follow-up in clinical trials.
Following short-term treatment with PROTONIX, elevated gastrin levels return to normal by at least 3 months.
Enterochromaffin-Like (ECL) Cell Effects
In 39 patients treated with oral pantoprazole 40 mg to 240 mg daily (majority receiving 40 mg to 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 to 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 concentrations. The high density of ECL cells in the rat stomach makes this species highly susceptible to the proliferative effects of elevated gastrin concentrations 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 Nonclinical Toxicology (13.1)].
Pharmacokinetics
PROTONIX Delayed-Release Tablets are prepared as enteric-coated tablets 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 with normal liver function receiving an oral dose of the enteric-coated 40 mg pantoprazole tablet, the peak concentration (Cmax) is 2.5 μg/mL; the time to reach the peak concentration (tmax) is 2.5 h, and the mean total area under the plasma concentration versus time curve (AUC) is 4.8 μg•h/mL (range 1.4 to 13.3 μg•h/mL). Following intravenous administration of pantoprazole to extensive metabolizers, its total clearance is 7.6‑14.0 L/h, and its apparent volume of distribution is 11.0‑23.6 L.
A single oral dose of PROTONIX For Delayed-Release Oral Suspension, 40 mg, was shown to be bioequivalent when administered to healthy subjects (N = 22) as granules sprinkled over a teaspoonful of applesauce, as granules mixed with apple juice, or mixed with apple juice followed by administration through a nasogastric tube. The plasma pharmacokinetic parameters from a crossover study in healthy subjects are summarized in Table 5.
Pharmacokinetic Parameters | Granules in Applesauce | Granules in Apple Juice | Granules in Nasogastric Tube |
|---|---|---|---|
| a Median values are reported for Tmax. | |||
| AUC (µg•hr/mL) | 4.0 ± 1.5 | 4.0 ± 1.5 | 4.1 ± 1.7 |
| Cmax (µg/mL) | 2.0 ± 0.7 | 1.9 ± 0.5 | 2.2 ± 0.7 |
| Tmax (hr)a | 2.0 | 2.5 | 2.0 |
After administration of a single or multiple oral 40 mg doses of PROTONIX Delayed-Release Tablets, the peak plasma concentration of pantoprazole was achieved in approximately 2.5 hours, and Cmax was 2.5 μg/mL. Pantoprazole undergoes little first-pass metabolism, resulting in an absolute bioavailability of approximately 77%. Pantoprazole absorption is not affected by concomitant administration of antacids.
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