In common with other anti-ulcer therapies, the possibility of malignant gastric tumour should be excluded when treating a gastric ulcer with lansoprazole because lansoprazole can mask the symptoms and delay the diagnosis.
Lansoprazole should not be co-administered with HIV protease inhibitors, such as atazanavir and nelfinavir, because there is a significant reduction in its bioavailability since the absorption of these depends on the intragastric acid pH (see section 4.5).
Severe hypomagnesaemia has been reported in patients treated with proton pump inhibitors (PPIs) like lansoprazole 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 PPIs 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.
Influence on the absorption of vitamin B12:
Lansoprazole, like all medicines that block acid secretion, can reduce the absorption of vitamin B12 (cyanocobalamin) due to hypochlorhydria or achlorhydria. This should be taken into account in long-term treatments in patients with vitamin B12 deficiency or with risk factors of reduced absorption of this vitamin, or in case clinical symptoms are observed.
Lansoprazole should be used with caution in patients with moderate and severe hepatic dysfunction (see sections 4.2 and 5.2).
Lansoprazole, like all proton pump inhibitors (PPIs), can increase gastric counts of bacteria normally present in the gastrointestinal tract. This can increase the risk of gastrointestinal infections caused by bacteria such as Salmonella, Campylobacter and Clostridium difficile.
In patients suffering from gastro-duodenal ulcers, the possibility of H. pylori infection as an etiological factor should be considered.
If lansoprazole is used in combination with antibiotics for eradication therapy of H. pylori, then the instructions for the use of these antibiotics should also be followed.
Because of limited safety data for patients on maintenance treatment for longer than 1 year, regular review of the treatment and a thorough risk/benefit assessment should regularly be performed in these patients
Very rarely cases of colitis have been reported in patients taking lansoprazole. Therefore, in the case of severe and/or persistent diarrhoea, discontinuation of therapy should be considered.
The treatment for the prevention of peptic ulceration of patients in need of continuous NSAID treatment should be restricted to high risk patients (e.g. previous gastrointestinal bleeding, perforation or ulcer, advanced age, concomitant use of medication known to increase the likelihood of upper GI adverse events [e.g. corticosteroids or anticoagulants], the presence of a serious co-morbidity factor or the prolonged use of NSAID maximum recommended doses).
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 the elderly 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.
Renal impairment
Acute tubulointersticial nephritis (TIN) has been observed in patients taking lansoprazole and may occur at any point during lansoprazole therapy (see section 4.8). Acute tubulointersticial nephritis can progress to renal failure.
Lansoprazole should be discontinued in case of suspected TIN, and appropriate treatment should be promptly initiated.
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 Lansoprazole. SCLE after previous treatment with a proton pump inhibitor may increase the risk of SCLE with other proton pump inhibitors.
Interference with laboratory tests
Increased Chromogranin A (CgA) level may interfere with investigations for neuroendocrine tumours. To avoid this interference, Lansoprazole treatment should be stopped for at least 5 days before CgA measurements (see section 5.1). 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.
As Lansoprazole contains sucrose, patients with rare hereditary intolerance to fructose, problems with glucose or galactose absorption or sucrose-isomaltase deficiency should not take this medicinal product.