Iron compounds Antacids

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

A1P04, used in cements and as an antacid (c) iron(II) hydroxide, Fe(OH)2 (d) Select two soluble ionic compounds that, when mixed in solution, form each of the insoluble compounds in parts (a), (b), and (c). Identify the spectator ions. 

Q4 Constipation can be a troublesome side effect of opiates used for pain relief, for example morphine and codeine. It is also a side effect of some calcium channel blocking agents, antacids containing aluminium compounds and iron salts used in the treatment of anaemia. 

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. 

Iron usually occurs as the Fe(III) form in food. This is also the form released from iron pots when food is cooked in them. However, iron must be in the Fe(II) state to be absorbed. Reduction from Fe(III) to Fe(II) can be accomplished by ascorbate (vitamin C) or by succinate. Factors that affect absorption include the solubility of a given compound of iron, the presence of antacids in the digestive tract, and the source of the iron. To give some examples, iron may form insoluble complexes with phosphate or oxalate, and the presence of antacids in the digestive tract may decrease iron absorption. Iron from meats is more easily absorbed than iron from plant sources. 

Aluminum compounds— The amounts of aluminum that most people consume in the form of food additives—mainly present in such items eis baking powder, pickles, and processed cheeses are probably less than that ingested by people who regularly take aluminum-containing antacids. For example, 3 1/2 oz (100 g) of one brand of processed American cheese was found to contain 70 mg of aluminum, which is about the amount present in a single tablet of a commonly used antacid. Nevertheless, even small amounts of aluminum may form nonabsorbable complexes with essential trace elements such as iron. 

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