ranitidine (Zantac, Gastrosedol)
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Introduction
Tradename: Zantac. (ranitidine hydrochloride)
Indications
- peptic ulcer disease
- gastroesophageal reflux (GERD)
- erosive esophagitis
- part of a multidrug regimen for treatment of H. pylori
- prevention of upper GI bleed due to hypersecretory conditions
- prophylaxis for stress ulceration
Dosage
- peptic ulcer disease:
- erosive esophagitis: 150 mg PO QID or 300 mg PO BID
- stress ulcer prophylaxis:
- IV administration:
Tabs: 150, 300 mg.
Syrup: 75 mg/5 mL.
Injection: 25 mg/mL (2 mL, 10 mL)
Dosage adjustment in renal failure
- creatinine clearance < 50 mg/min
Pharmacokinetics
- oral bioavailability is about 55%
- 15% of the drug is protein-bound
- elimination 1/2life is 2 hours; increases to 7 hours in patients with renal failure
- major metabolite is N-oxide
elimination via kidney
elimination via liver
1/2life = 0.9-2.3 hours
protein binding = 12-18 %
elimination by hemodialysis = +
Adverse effects
- not common (1-10%)
- uncommon (< 1%)
- other
- increases serum transaminases (rare)
- anticholinergic activity 22% that of atropine
Drug interactions
- ranitidine inhibits metabolism of
- ranitidine increases bioavailability of midazolam
- ramitidine decreases renal clearance of procainamide
- lidocaine
- carbamazepine
- benzodiazepines
- alcohol
- ketoconazole
- antacids reduce ranitidine absorption
Laboratory
- specimen: serum, plasma (heparin, EDTA), urine
- methods: HPLC, RIA
- interferences: RIA: some cross-reactivity with N-oxide metabolite
Mechanism of action
- H2 receptor antagonist
- some cyt P450 inhibition , but less than cimetidine
Notes
- N-nitrosodimethylamine (NDMA) found in some ranitidine products including Zantac[6]
- levels of NDMA in ranitidine products similar to those in grilled or smoked meats[7]
- FDA recommends removal of all ranitidine drugs from the market due to concerns that NDMA content increases over time 7 when stored above room temperature[8]
- paper alleging that rantidine increases urinary NMMA retracted[9]
- rantidine does not increase urinary NMMA in normal healthy adults[10]
More general terms
Component of
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed, WB Saunders, Philadelpha 1995
- ↑ Journal Watch 25(3):26-27, 2005 Carnahan RM, Lund BC, Perry PJ, Chrischilles EA. The concurrent use of anticholinergics and cholinesterase inhibitors: rare event or common practice? J Am Geriatr Soc. 2004 Dec;52(12):2082-7. PMID: https://www.ncbi.nlm.nih.gov/pubmed/15571547
- ↑ 6.0 6.1 FDA Safety Alert. Sept 13, 2019 Zantac (ranitidine): Safety Information - NDMA Found in Samples of Some Ranitidine Medicines. https://www.fda.gov/safety/medwatch-safety-alerts-human-medical-products/zantac-ranitidine-safety-information-ndma-found-samples-some-ranitidine-medicines
FDA Safety Alert. Sept 23, 2019 Sandoz Inc. Issues Voluntary Recall of Ranitidine Hydrochloride Capsules 150mg and 300mg Due to An Elevated Amount of Unexpected Impurity, N-Nitrosodimethylamine (NDMA), in the Product https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/sandoz-inc-issues-voluntary-recall-ranitidine-hydrochloride-capsules-150mg-and-300mg-due-elevated - ↑ 7.0 7.1 Woodcock J. Director - Center for Drug Evaluation and Research FDA News Release. Nov 1, 2019 Statement on new testing results, including low levels of impurities in ranitidine drugs. https://www.fda.gov/news-events/press-announcements/statement-new-testing-results-including-low-levels-impurities-ranitidine-drugs
- ↑ 8.0 8.1 FDA News Release. April 1, 2020 FDA Requests Removal of All Ranitidine Products (Zantac) from the Market. https://www.fda.gov/news-events/press-announcements/fda-requests-removal-all-ranitidine-products-zantac-market
- ↑ 9.0 9.1 Retraction Watch Staff Widely Covered Paper on Ranitidine-Cancer Link Retracted. Medscape 2021. June 15 https://www.medscape.com/viewarticle/953118
Zeng T, Mitch WA Retracted: Oral intake of ranitidine increases urinary excretion of N-nitrosodimethylamine. Carcinogenesis, Volume 37, Issue 6, June 2016, Pages 625-634 https://academic.oup.com/carcin/article/37/6/625/1744630 - ↑ 10.0 10.1 Florian J, Matta MK, DePalma R et al Effect of Oral Ranitidine on Urinary Excretion of N-Nitrosodimethylamine (NDMA). A Randomized Clinical Trial. JAMA. Published online June 28, 2021 PMID: https://www.ncbi.nlm.nih.gov/pubmed/34180947 https://jamanetwork.com/journals/jama/fullarticle/2781670
White CM, Hernandez AV. Ranitidine and Risk of N-Nitrosodimethylamine (NDMA) Formation. JAMA. Published online June 28, 2021 PMID: https://www.ncbi.nlm.nih.gov/pubmed/34180953 https://jamanetwork.com/journals/jama/fullarticle/2781671