Magnesium hydroxide Cimetidine

Drugs that may affect mexiletine include aluminum-magnesium hydroxide, atropine, narcotics, cimetidine, fluvoxamine, hydantoins, metoclopramide, propafenone, rifampin, urinary acidifiers, and urinary alkalinizers. 

Drugs that have been associated with elevations in quinidine concentrations include acetazolamide, the antacids magnesium hydroxide and calcium carbonate, and the H2-receptor antagonist cimetidine. Cimetidine inhibits the hepatic metabolism of quinidine. Phenytoin, rifampin, and barbiturates increase the hepatic metabolism of quinidine and reduce its plasma concentrations. 

The pharmacokinetics of a singie dose of metrifonate were not ai-tered by an antacid containing aiuminium/magnesium hydroxide, nor by pretreatment with cimetidine or ranitidine. 

No adverse interactions appear to occur with clopidogrel and alu-minium/magnesium hydroxide, atenolol, cimetidine, digoxin, food, insulin, nifedipine, oestrogens, phenobarbital, phenytoin or tolbutamide. 

The manufacturers warn of the possible risks of giving ziprasidone with drugs that prolong the QT interval, and of the possible antagonism that may occur with ievodopa and other dopamine agonists. Ziprasidone appears not to interact to a clinically relevant extent with an aiuminium/magnesium hydroxide antacid, benzatropine, cimetidine, iorazepam, propranolol or tobacco smoking. 

A single 40-mg oral dose of ziprasidone were given to 10 healthy subjects either alone, with cimetidine 800 mg daily for 2 days, or with three 30-mL doses of Maalox (aiuminium/magnesium hydroxide). The only change in the pharmacokinetics of ziprasidone was a 6% increase in the AUC with cimetidine. It was concluded that no special precautions are needed if ei-... 

When 12 healthy subjects were given oral cimetidine 300 mg four times daily for 5 doses, with and without 30 mL of Mylanta 11 (aluminium/magnesium hydroxide mixture), the absorption of cimetidine was unaffected. No interaction was found in other single-dose studies using aluminium phosphate or aluminium/magnesium hydroxide" antacids. 

Allgayer H, Rollinghoff W, Paumgartner G. Absence of in vivo and in vitro interactions of an aluminium hydroxide, magnesium hydroxide containii antacid with cimetidine in patients with peptic ulcer. Z Gastroenterol (1983) 21,351-4. 

Why are cimetidine and ranitidine better antacids than sodium hydrogencarbonate or magnesium or aluminium hydroxide ... 

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