INFORMATION FOR HEALTH PROFESSIONALS
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SOMAC is in the form of a yellow, oval, biconvex enteric-coated tablet with a white to off white core containing pantoprazole sodium sesquihydrate 22.6mg or 45.1mg (corresponding to pantoprazole tablet SOMAC 20.0mg and 40.0mg respectively) and is a gastro-resistant tablet for oral use.
Pantoprazole is a substituted benzimidazole which inhibits the secretion of hydrochloric acid in the stomach by specific action on the proton pumps of the parietal cells.
Pantoprazole is converted to its active form in the acidic canaliculi of the parietal cells when it inhibits the H+, K+-ATPase enzyme, i.e. the final stage in the production of hydrochloric acid in the stomach. The inhibition is dose-dependent and affects both basal and stimulated acid secretion. In most patients, freedom from symptoms is achieved in 2 weeks. As with other proton pump inhibitors and H2 receptor inhibitors, treatment with pantoprazole causes a reduced acidity in the stomach and thereby an increase in gastrin in proportion to the reduction in acidity. The increase in gastrin is reversible. Since pantoprazole binds to the enzyme distal to the cell receptor level, the substance can affect hydrochloric acid secretion independently of stimulation by other substances (acetylcholine, histamine, gastrin). The effect is the same whether the product is given orally or intravenously.
The fasting gastrin values increase under pantoprazole. On short-term use, in most cases they do not exceed the normal upper limit. During long-term treatment, gastrin levels double in most cases. An excessive increase, however, occurs in isolated cases. As a result, a mild to moderate increase in the number of specific endocrine (ECL) cells in the stomach is observed in a minority of cases during long-term treatment (simple to adenomatoid hyperplasia). However, according to the studies conducted so far, the formation of carcinoid precursors (atypical hyperplasia) or gastric carcinoids as were found in animal experiments can be ruled out for humans for a 1-year treatment period.
An influence of a long-term treatment with pantoprazole exceeding one year cannot be completely ruled out on endocrine parameters of the thyroid and liver enzymes according to results in animal studies.
Pantoprazole is rapidly absorbed and the maximal plasma concentration is achieved even after a single oral dose. On average at about 2.0 h - 2.5 h p.a. the maximum serum concentrations of about 1 - 1.5µg/mL (SOMAC 20mg) and 2 - 3µg/mL (SOMAC 40mg) are achieved, and these values remain constant after multiple administration. Volume of distribution is about 0.15 L/kg and clearance is about 0.1 L/h/kg. Terminal half-life is about 1 h. There were a few cases of subjects with delayed elimination. Because of the specific binding of pantoprazole to the proton pumps of the parietal cell the elimination half-life does not correlate with the much longer duration of action (inhibition of acid secretion).
Pharmacokinetics do not vary after single or repeated administration. In the dose range of 10 to 80mg, the plasma kinetics of pantoprazole are virtually linear after both oral and intravenous administration.
Pantoprazole's serum protein binding is about 98%. The substance is almost exclusively metabolized in the liver. Renal elimination represents the major route of excretion (about 80%) for the metabolites of pantoprazole, the rest are excreted with the faeces. The main metabolite in both the serum and urine is desmethylpantoprazole which is conjugated with sulphate. The half-life of the main metabolite (about 1.5 h) is not much longer than that of pantoprazole.
Pantoprazole is completely absorbed after oral administration. The absolute bioavailability from the tablet was found to be about 77%. Concomitant intake of food had no influence on AUC, maximum serum concentration and thus bioavailability. Only the variability of the lag-time will be increased by concomitant food intake.
No dose reduction is requested when pantoprazole is administered to patients with restricted kidney function (including dialysis patients). As with healthy subjects, pantoprazole's half-life is short. Only very small amounts of pantoprazole can be dialysed. Although the main metabolite has a moderately delayed half-life (2 - 3h), excretion is still rapid and thus accumulation does not occur.
For patients with liver cirrhosis (classes A and B according to Child) the half-life values increased to between 3-6 h (SOMAC 20mg) and 7-9 h (SOMAC 40mg), and the AUC values increased by a factor of 3-5 (SOMAC 20mg) and between 5-7 (SOMAC 40mg). However, the maximum serum concentration only increased slightly by a factor of 1.3 (SOMAC 20mg) and 1.5 (SOMAC 40mg) compared with healthy subjects.
A slight increase in AUC and Cmax in elderly volunteers compared with younger counterparts is also not clinically relevant.
The NIH have recommended that regimens to eradicate H. pylori in patients with PUD should contain both anti-secretory agents and anti-microbial agents (to which H. pylori has been demonstrated to be sensitive in vivo). A trial by Bardhan in patients with gastritis, florid duodenal ulcer or history of duodenal ulcer has demonstrated that pantoprazole 40mg twice daily in the combination with tinidazole 500mg twice daily and clarithromycin 250mg twice daily for 10 days is effective in eradicating H. pylori in 86% of cases. Following combination therapy the DU healing rate was 100% after 1 month.
SOMAC is indicated for maintenance treatment of reflux oesophagitis, duodenal ulcer, gastric ulcer and Zollinger-Ellison syndrome. Prolonged treatment should be considered:
In H. pylori positive patients with gastric and duodenal ulcers, eradication of the germ by a combination therapy should be achieved. One of the following combinations of SOMAC with antibiotics is effective.
In the case of combination therapy the datasheets of the respective drugs should be observed.
Combination therapy involving metronidazole must only be used if the other combination partners are contraindicated, since damage to human germ cells by metronidazole cannot be excluded and animal studies revealed an increased incidence of certain tumours.
SOMAC gastro-resistant tablets should not be chewed or crushed, and should be swallowed whole with some liquid. For eradication of H. pylori, convenient dosing could be at breakfast and dinner times. The combination therapy is implemented for 7 days. If, to ensure healing of the ulcers, further treatment with pantoprazole is indicated, the dosage recommendations for duodenal and gastric ulcers should be considered.
If combination therapy is not an option, e.g. if the patient has tested negative for H. pylori, the following dosage guidelines apply for SOMAC monotherapy:
The recommended oral dosage is one gastro-resistant tablet SOMAC 40mg per day. A duodenal ulcer generally heals within 2 weeks. If a 2-week period of treatment is not sufficient, healing will be achieved in almost all cases within a further 2 weeks.
The recommended oral dosage is one gastro-resistant tablet SOMAC 40mg per day.
A 4-week period is usually required for the treatment of gastric ulcers. If this is not sufficient, healing will usually be achieved within a further 4 weeks.
For mild reflux disease and the associated symptoms, the recommended dosage is one SOMAC 20mg tablet per day. Symptom relief is generally accomplished within 2-4 weeks. If symptom control has not been achieved after four weeks treatment with SOMAC 20mg tablets daily, further investigation is recommended.
For treatment of reflux oesophagitis, the recommended oral dosage is one SOMAC 40mg tablet per day. A 4-week period is usually required for treatment of reflux oesophagitis, however if this is not sufficient, healing will usually be achieved within a further 4 weeks.
The recommended oral dosage is one gastro-resistant tablet SOMAC 40mg per day.
The recommended oral dosage is one gastro-resistant tablet SOMAC 20mg per day.
Duodenal and Gastric Ulcer, and Zollinger-Ellison Syndrome:
For long-term management, a maintenance dose of one gastro-resistant tablet SOMAC 40mg per day is recommended.
Reflux Oesophagitis
A maintenance dose of one SOMAC 20mg tablet per day is recommended, increasing to 40mg per day if relapse occurs. After healing of the relapse the dosage can be reduced again to 20mg SOMAC.
Experience with long-term administration in man over several years is available in a limited number of patients. Therefore, long-term treatment exceeding 1 year may be considered after careful evaluation of the risk benefit ratio. Patients should then be kept under regular surveillance.
There are no data currently available on the use of pantoprazole in children.
The daily dose of 20 mg or 40mg can be given. An exception is combination therapy for eradication of H. pylori, where also elderly patients should receive the usual pantoprazole dose (2 x 40mg/day) during 1-week treatment.
The daily dose of 20mg or 40mg can be given.
In patients with severe liver impairment the dose has to be reduced to 20mg pantoprazole per day.
SOMAC should generally not be used in cases of known hypersensitivity to one of the constituents of SOMAC or of the combination partners.
SOMAC must not be used in combination treatment for eradication of H. pylori in patients with moderate to severe hepatic or renal dysfunction since currently no data are available on the efficacy and safety of SOMAC in combination treatment of these patients.
Pantoprazole, like other proton pump inhibitors, should not be co-administered with atazanavir (see Interactions).
In patients with severe liver impairment the liver enzymes should be monitored regularly during treatment with pantoprazole, particularly on long-term use. In the case of a rise of the liver enzymes SOMAC should be discontinued.
In the presence of any alarm symptom (e.g. significant unintentional weight loss, recurrent vomiting, dysphagia, haematemesis, anaemia or melaena) and when gastric ulcer is suspected or present, malignancy should be excluded, as treatment with pantoprazole may alleviate symptoms and delay diagnosis. Further investigation is to be considered if symptoms persist despite adequate treatment.
The use of SOMAC 20mg as a preventive of gastroduodenal ulcers induced by non-selective non-steroidal anti-inflammatory drugs (NSAIDs) should be restricted to patients who require continued NSAID treatment and have an increased risk to develop gastrointestinal complications. The increased risk should be assessed according to individual risk factors, e.g. high age (>65 years), history of gastric or duodenal ulcer or upper gastrointestinal bleeding.
Generally, daily treatment with any acid-blocking medicines over a long time (e.g. longer than 3 years) may lead to malabsorption of cyanocobalamin caused by hypo- or achlorhydria. Rare cases of cyanocobalamin deficiency under acid-blocking therapy have been reported in the literature. This should be considered if respective clinical symptoms are observed.
To date there has been no experience with treatment in children.
In long-term treatment, especially when exceeding a treatment period of 1 year, patients should be kept under regular surveillance.
Patients being treated for mild reflux disease and associated symptoms with SOMAC 20 mg, who do not respond after 4 weeks, should be investigated.
In the case of combination therapy the datasheets of the respective drugs should be observed.
Clinical experience in pregnant women is limited. In animal reproduction studies, signs of slight foetotoxicity were observed at doses above 5mg/kg. There is no information on the excretion of pantoprazole into human breast milk. Pantoprazole tablets should only be used when the benefit to the mother is considered greater than the potential risk to the foetus/baby.
There are no known effects on the ability to drive and use machines.
Very common (≥10%), common (≥1% - <10%), uncommon (≥0.1% - <1%), rare (≥0.01% - <0.1%), Very rare (<0.01%)
Common: Gastrointestinal complaints such as upper abdominal pain, diarrhoea, constipation or flatulence
Uncommon: nausea, vomiting
Rare: dry mouth
Very rare: Peripheral oedema
Very rare: Severe hepatocellular damage leading to jaundice with or without hepatic failure
Very rare: Anaphylactic reactions including anaphylactic shock
Investigations:
Very rare: Increased liver enzymes (transaminases, γ-GT), elevated triglycerides, increased body temperature
Rare: Arthralgia
Very rare: Myalgia
Common: Headache
Uncommon: Dizziness, disturbances in vision (blurred vision)
Rare: Depression, hallucination, disorientation and confusion, especially in pre-disposed patients, as well as the aggravation of these symptoms in case of pre-existence
Very rare: Interstitial nephritis
Uncommon: Allergic reactions such as pruritus and skin rash
Very rare: Urticaria; angioedema; severe skin reactions such as Stevens-Johnson Syndrome, erythema multiforme, Lyell-Syndrome; photosensitivity.
SOMAC may reduce or increase the absorption of drugs whose bioavailability is pH-dependent (e.g. ketoconazole).
Pantoprazole is metabolized in the liver via the cytochrome P450 enzyme system. An interaction of pantoprazole with other drugs or compounds which are metabolized using the same enzyme system cannot be excluded. However, no clinically significant interactions were observed in specific tests with a number of such drugs or compounds, namely carbamazepine, caffeine, diazepam, diclofenac, digoxin, ethanol, glibenclamide, antipyrine, metoprolol, naproxen, nifedipine, phenytoin, piroxicam, theophylline, and an oral contraceptive.
Although no interaction during concomitant administration of phenprocoumon or warfarin has been observed in clinical pharmacokinetic studies, a few isolated cases of changes in international normalised ratio (INR) have been reported during concomitant treatment in the post-marketing period. Therefore, in patients being treated with coumarin anticoagulants, monitoring of prothrombin time / INR is recommended after initiation, termination or during irregular use of pantoprazole.
There were also no interactions with concomitantly administered antacids.
It has been shown that co-administration fo atazanavir 300 mg/ritonavir 100 mg with omeprazole (40 mg once daily) or atazanavir 400 mg with lansoprazole (60 mg single dose) to healthy volunteers resulted in substantial reduction in the bioavailability of atazanavir. The absorption of atazanavir is pH dependent. Therefore, proton pump inhibitors, including pantoprazole, should not be co-administered with atazanavir (see Contraindications).
There are no known symptoms of overdosage in man.
Doses up to 240mg i.v. were administered over two minutes and were well tolerated.
In the case of overdosage with clinical signs of intoxication, the usual rules of intoxication therapy apply.
Contact the Poisons Information Centre for advice on the management of an overdose.
Store below 30°C.
Prescription medicine.
20mg and 40mg tablets in Alu-Alu blisters x 30s
Preclinical data reveal no special hazard to humans based on conventional studies of safety pharmacology, repeated dose toxicity and genotoxicity.
In a 2-year carcinogenicity study (corresponding to lifetime treatment) in rats, neuroendocrine neoplasms were found. In addition, squamous cell papillomas were found in the forestomach of rats in one study. The mechanism leading to the formation of gastric carcinoids by substituted benzimidazoles has been carefully investigated and allows the conclusion that it is a secondary reaction to the massively elevated serum gastrin levels occurring in the rat during chronic treatment.
In the two-year studies an increased number of liver tumours was observed in rats and in female mice and was interpreted as being due to pantoprazole's high metabolic rate in the liver. From mutagenicity studies, cell transformation tests and a DNA binding study it is concluded that pantoprazole has no genotoxic potential.
A slight increase of neoplastic changes of the thyroid was observed in the group of rats receiving the highest dose. The occurrence of these neoplasms is associated with the pantoprazole-induced changes in the breakdown of thyroxine in the rat liver. As the therapeutic dose in man is low, no side effects on the thyroid glands are expected.
Investigations revealed no evidence of impaired fertility or teratogenic effects. Penetration of the placenta was investigated in the rat and was found to increase with advanced gestation. As a result, concentration of pantoprazole in the foetus is increased shortly before birth.
Mylan New Zealand Ltd
PO Box 11-183
Ellerslie
Auckland, New Zealand
Toll Free number: 0800 456 89825
2 February 2009
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