Penicillamine Antacids

PENICILLAMINE ANTACIDS 1 penicillamine levels 1 absorption of penicillamine Avoid co-administration... 

Penicillamine Antacids (containing Ap and/or Mg ), iron compounds, food Formation of less soluble penicillamine chelates resulting in reduced absorption of penicillamine... 

There is an increased risk of toxicity of MTX when administered with the NSAIDs, salicylates, oral antidiabetic drugs, phenytoin, tetracycline, and probenecid. There is an additive bone marrow depressant effect when administered with other drug known to depress the bone marrow or with radiation therapy. There is an increased risk for nephrotoxicity when MTX is administered with other drug that cause nephrotoxicity. When penicillamine is administered with digoxin, decreased blood levels of digoxin may occur. There is a decreased absorption of penicillamine when the dmg is administered with food, iron preparations, and antacids. 

The absorption of oral iron is decreased when tlie agent is administered with antacids, tetracyclines, penicillamine, and the fluoroquinolones. When iron is administered with levothyroxine, there may be a decrease in tlie effectiveness of levothyroxine When administered orally, iron deceases the absoqition of lev-odopa. Ascorbic acid increases tlie absoqition of oral iron. Iron dextran administered concurrently with chloramphenicol increases serum iron levels. 

Do not take antacids, tetracyclines, penicillamine, or fluoroquinolones at the same time or 2 hours before or after taking iron without first checking with the primaiy health care provider. 

Penicillamine is well absorbed (40-70%) from the gastro-intestinal tract and, therefore, has a decided advantage over many chelating agents. Food, antacids, and iron reduce its absorption, so it should be taken on an empty stomach. Preferably, the... 

Antacids Penicillamine 1 The absorption of penicillamine is decreased by 66% with coadministration of antacids. 

Drugs that may affect penicillamine include gold therapy, antimalarial or cytotoxic drugs, iron salts, antacids, and food. 

Antacids that contain aluminium or magnesium can reduce the absorption of penicillamine by up to 45%, presumably because increased gastric pH favors oxidation to the poorly absorbed disulfide (182,398,399). 

Osman MA, Patel RB, Schnna A, Snndstrom WR, Welling PG. Reduction in oral penicillamine absorption by food, antacid, and ferrous sulfate. CUn Pharmacol Ther 1983 33(4) 465-70. 

Ifan A, Welling PG. Pharmacokinetics of oral 500-mg penicillamine effect of antacids on absorption. Biopharm Drug Dispos 1986 7(4) 401-5. 

Clinically important, potentially hazardous interactions with acitretin, antacids, cholestyramine, dapsone, furazolidone, halofantrine, hydroxychloroquine, methotrexate, methoxsalen, mivacurium, nilotinib, penicillamine, sulfonamides... 

Antacids form insoluble metal ion chelates with tetracyclines, 4-quinolone antibacterials and penicillamine. 

Penicillamine is well absorbed (40-70%) from the GI tract and therefore has a decided advantage over many other chelating agents. Food, antacids, and iron reduce its absorption. Peak concentrations in blood are obtained 1—3 hours after administration. Unlike cysteine, its nonmethylated parent compound, penicillamine, is somewhat resistant to attack by cysteine desulfhydrase or L-amino acid oxidase and is relatively stable in vivo. Hepatic biotransformation is responsible for most of the degradation of penicillamine, and very little is excreted unchanged. Metabolites are found in both urine and feces. 

B. Several drugs (eg, antacids and ferrous sulfate) and food can substantially reduce gastrointestinal absorption of penicillamine. 

The absorption of penicillamine from the gut can be reduced by 30 to 40% if antacids containing aluminium/magnesium hydroxide are taken. 

The most likely explanation is that the penicillamine forms less soluble chelates with magnesium and aluminium ions in the gut, which reduces its absorption. Another idea is that the penicillamine is possibly less stable at the higher pH values caused by the antacid. ... 

Osman MA, Patel RB, Schuna A, Sundstrom WR, Welling PG Reduction in oral penicillamine absorpticm by food, antacid and ferrous sulii ate. Clin Pharmacol Ther( 9Z ) 33,465-70. 

An active substance, although initially released from its dosage form (and dissolved), may become unavailable for absorption due to reactimis with other medicines or food components [4]. An example is the formation of insoluble complexes of tetracycline with calcium or aluminium ions from antacids or milk products. Interaction (chelation or binding) with iron ions leads to a reduced absorption for a variety of active substances such as doxycycline, penicillamine, methyldopa and ciprofloxacin. The absorption of active substances showing pH-dependent dissolution behaviour may be influenced by medicines that influence the gastric pH, such as H2-antagonists, proton pump inhibitors and antacids. Antimycotic active substances such as ketoconazole or itraconazole dissolve better in acidic fluids. Therefore their bioavailability may be increased by the concomitant use of an acidic drink like cola, whereas the concomitant use of antacids or proton pump inhibitors is likely to reduce the bioavailability. Concomitant use of milk may increase the dissolution of acidic active substances, whereas fats from food may increase the bioavailability of lipophilic active substances like albendazole and griseofulvin. 

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