Omeprazole adverse effects

The effects of omeprazole 40 mg/day and esomeprazole 40 mg/day for 5 days on intragastric acidity have been compared in an open, crossover study in 130 patients with symptoms of gastro-esophageal reflux (20). Esomeprazole provided more effective acid control than twice the standard dose of omeprazole. Adverse effects were similar with the two drugs, and the most commonly reported were headache, nausea, and abdominal pain. 

Vitamin B12 generally is well tolerated and exhibits minimal adverse effects. Injection-site pain, pruritus, rash, and diarrhea have been reported. Drug interactions have been observed with omeprazole and ascorbic acid that decrease oral absorption. 

Gastrointestinal ulceration may occur less frequently than with some other NSAIDs. A preparation combining diclofenac and misoprostol decreases upper gastrointestinal ulceration but may result in diarrhea. Another combination of diclofenac and omeprazole was also effective with respect to the prevention of recurrent bleeding, but renal adverse effects were common in high-risk patients. Diclofenac, 150 mg/d, appears to impair renal blood flow and glomerular filtration rate. Elevation of serum aminotransferases occurs more commonly with this drug than with other NSAIDs. 

Omeprazole can impair benzodiazepine metabolism and lead to adverse effects (SEDA-18, 43). 

Omeprazole, like cimetidine, can impair benzodiazepine metabolism and lead to adverse effects (SEDA-18, 43). Other drugs, including antibiotics (erythromycin, chloramphenicol, isoniazid), antifungal drugs (ketoconazole, itraconazole, and analogues), some SSRIs (fluoxetine, paroxetine), other antidepressants (nefazodone), protease inhibitors (saquinavir), opioids (fentanyl), calcium channel blockers (diltiazem, verapamil), and disulfiram also compete for hepatic oxidative pathways that metabolize most benzodiazepines, as well as zolpidem, zopiclone, and buspirone (SEDA-22,39) (SEDA-22,41). 

NIFEDIPINE PROTON PUMP INHIBITORS - OMEPRAZOLE Possible t efficacy and adverse effects Small t in bioavailability possible via t intragastric pH Unlikely to be clinically significant... 

MOCLOBEMIDE PROTON PUMP INHIBITORS -OMEPRAZOLE/ ESOMEPRAZOLE Possible t efficacy and adverse effects of modobemide Inhibition of CYP2C19 Monitor more closely effect only seen in extensive CYP2C19 metabolizers. Dose i may be required... 

PHENYTOIN PROTON PUMP INHIBITORS Possible t efficacy and adverse effects of phenytoin Unclear possible altered metabolism via CYP2C19 1 dose may be required. Use the proton pump inhibitor regularly, not PRN monitor phenytoin levels when starting or stopping treatment. Patients have received omeprazole for 3 weeks without altered phenytoin levels. Effect not reported with pantoprazole or rabeprazole... 

ALMOTRIPTAN, ELETRIPTAN, ZOLMITRIPTAN H2-RECEPT0R BLOCKERS -CIMETIDINE t efficacy and adverse effects of zolmitriptan, e.g. flushing, sensations of tingling, heat, heaviness, pressure or tightness of any part of body including the throat and chest, dizziness Inhibition of metabolism via CYP1A2 Consider alternative acid suppression, e.g. H2 antagonist or proton pump inhibitors (not omeprazole or lansoprazole), or monitor more closely and l maximum dose of zolmitriptan to 5 mg/24 hours... 

PRAMIPEXOLE, ROPINIROLE H2-RECEPTOR BLOCKER-CIMETIDINE T efficacy and adverse effects of pramipexole 1 renal excretion of pramipexole by inhibition of cation transport system. Inhibition of CYP1A2-mediated metabolism of ropinirole Monitor closely i dose of pramipexole may be required. Adjust dose of ropinirole as necessaiy or use alternative acid suppression, e.g. H2 antagonist proton pump inhibitor (not omeprazole or lansoprazole)... 

BZDs PROTON PUMP INHIBITORS -OMEPRAZOLE/ ESOMEPRAZOLE T efficacy and adverse effects, e.g. prolonged sedation Inhibition of metabolism via CYP4S0 (some show competitive inhibition via CYP2C19) Monitor for t side-effects, and 1 dose as necessaiy. Likely to delay recovery after procedures for which BZDs have been used. Consider alternative proton pump inhibitor, e.g. lansoprazole or pantoprazole... 

DISULFIRAM PROTON PUMP INHIBITORS -OMEPRAZOLE Possible T adverse effects of disulfiram Accumulation of metabolites Monitor closely for T side-effects, although patients have received combinations without reported problems... 

CLARITHROMYCIN PROTON PUMP INHIBITORS -OMEPRAZOLE t efficacy and adverse effects of both drugs t plasma concentration of both drugs No dose adjustment recommended. Interaction considered useful for Helicobacter pylori eradication... 

VORICONAZOLE OMEPRAZOLE Possible t efficacy and adverse effects of both drugs 1. Inhibition of voriconazole metabolism via CYP2C19 and CYP3A4 2. Inhibition of metabolism of omeprazole 1. No dose adjustment of voriconazole is recommended 2. Halve the omeprazole dose... 

CIMETIDINE FAMOTIDINE NIZATIDINE, RANITIDINE BRONCHODILATORS -THEOPHYLLINE t efficacy and adverse effects, including seizures. There is conflicting information associated with ranitidine, famotidine and nizatidine Inhibition of metabolism via CYP1A2, cimetidine being the best known inhibitor Use alternative acid suppression, e.g. a proton pump inhibitor (not omeprazole or lansoprazole) or monitor closely considerable patient variation. Check levels on day 3 and then at 1 week. A 30-50% i dose of theophylline may be required. For doses <400 mg/day, the interaction may not be clinically significant... 

TRIPOTASSIUM DICITRATOBISMUTHATE PROTON PUMP INHIBITORS - OMEPRAZOLE t adverse effects of tripotassium dicitratobismuthate T absorption Do not use together for more than 16 weeks. Bismuth salicylate and subnitrate do not interact... 

Adverse effects include nausea, headache, diarrhoea, constipation and rash but are uncommon. Omeprazole inhibits the 2C family of the cytochrome P450 system, decreasing the metabolism of warfarin, diazepam, carbamazepine and phenytoin, and enhancing the action of these drugs (but inhibition is less than with cimetidine). 

A 74-year-old woman with seronegative rheumatoid arthritis was given sulfasalazine followed by methotrexate, both of which were withdrawn because of adverse effects. She also took prednisone 10 mg/day. She developed acute abdominal pain and fever (38.7 C) with no chills. Her serum amylase was 269 IU/1, serum lipase 300 IU/1, and urinary amylase 2895 IU/1. There was no evidence of tumor, hypertriglyceridemia, or lithiasis. In addition to prednisone, she was taking amlodipine, bromazepam, and omeprazole, none of which have been reported to cause pancreatitis. A marked improvement was noted after prednisone withdrawal. 

Esomeprazole is the 5-isomer of omeprazole. The pharmacology, pharmacokinetics, efficacy, and safety of esomeprazole have been reviewed (1). Esomeprazole produces acid control comparable to that of currently available proton pump inhibitors. It undergoes less hepatic metabolism than omeprazole, has an oral availability of 89% at a dose of 40 mg, and a half-life of 1.5 hours. Esomeprazole is well tolerated its common adverse effects are diarrhea, headache, nausea, abdominal pain, respiratory infection, and sinusitis. 

The MACH-2 study has assessed the role of omeprazole in triple therapy in 539 patients with duodenal ulcers associated with H. pylori (3). The addition of omeprazole resulted in significantly higher eradication rates (over 90%) than antibiotics alone (amoxicillin plus clarithromycin about 25% clarithromycin plus metronidazole 70%), and reduced the impact of primary resistance to metronidazole. About one-third of the patients who took amoxicillin reported diarrhea/loose stools. The frequency of taste disturbance was dose-dependent with clarithromycin. Increased liver enzymes were more commonly reported in those taking metronidazole. The addition of omeprazole did not increase the frequency of reported adverse effects. 

The DU-MACH study assessed the efficacy of two omeprazole-based triple therapies (omeprazole, amoxicillin, clarithromycin versus omeprazole, metronidazole, clarithromycin) given for 1 week to 149 patients for eradicating H. pylori, healing duodenal ulcers, and preventing ulcer relapse over 6 months after treatment (4). Both regimens achieved high eradication rates (about 90%) and were well tolerated. Adverse effects were similar in the two groups, and included diarrhea, taste disturbance, headache, nausea, and dyspepsia. 

Ranitidine 300 mg bd and omeprazole 20 mg bd have been compared as components of triple therapies (combining them with either amoxicillin plus clarithromycin or amoxicillin plus metronidazole) in 320 patients with H. pylori (5). Omeprazole and ranitidine combined with two antibiotics for 1 week were equally effective in eradicating H. pylori. This result questions the role of profound acid suppression in eradication. There was no difference in the reported adverse effects, which included nausea, vomiting, diarrhea, metallic taste, skin rashes, and headache. 

In a similar study in 221 patients with peptic ulcer disease associated with H. pylori, rabeprazole has been compared with omeprazole and lansoprazole (combining them with amoxicillin plus clarithromycin for 1 week) (6). Rabeprazole was as effective as omeprazole and lansoprazole in eradicating H. pylori (84-88% each). There were no differences in reported adverse events. Common adverse effects were soft stools, glossitis, taste disturbances, and skin rashes. 

Dual therapy (omeprazole plus clarithromycin) for 2 weeks has been compared with triple therapy (omeprazole plus amoxicillin and clarithromycin) for 1 week in the eradication of H. pylori in 145 patients with duodenal nlcers (7). Triple therapy was significantly more effective in eradicating H. pylori (71 versus 48%). There were no significant differences in comphance or adverse effects. The most freqnent adverse effects were metallic taste and nansea in the dnal-therapy gronp and metalhc taste, mild abdominal pain, and diarrhea in the triple-therapy group. 

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