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Drug Caution Code - Code I




Code I: Interaction

Use of this product may alter the effect of other drugs and interfere with their effectiveness.

Drug Caution Code "I" refers to:
Calcium salts
Magnesium salts
Aluminum salts
Iron salts
Bismuth salts
Urinary alkalizers such as sodium bicarbonate, sodium citrate, potassium citrate
Adsorbent antidiarrheals such as attapulgite, kaolin and pectin.

Calcium Salts Interact With:

Interaction

Mechanism

Management

Etidronate

Calcium prevents absorption

Do not take within 2 hours of calcium supplements

Fluroquinolones

Decreased absorption

Do not take within 2 hours of calcium supplements

Iron salts (oral)

Decreased absorption

Do not take within 2 hours of calcium supplements

Phenytoin

Decreased bioavailability

Do not take within 3 hours

Tetracyclines

Decreased absorption

Separate administration by 3 to 4 hours

Verapamil

Decreased effect of Verapamil

Do not take within 2 hours

Magnesium Salts Interact With:

Interaction

Mechanism

Management

Aminoquinolones (chloroquine)

Chloroquine adsorbed by magnesium

Separate doses by 2 to 4 hours

Penicillamine

Decreased bioavailability

Take penicillamine on an empty stomach, unaccompanied by magnesium salts

Tetracyclines

Decreased absorption

Separate doses by 2 to 4 hours.

Aluminum Salts Interact With:

Interaction

Mechanism

Management

Tetracyclines

Decreased absorption

Separate doses by 3 to 4 hours.

Penicillamine

Decreased bioavailability

Separate doses, possibly increase penicillamine dose

Antacids Interact With:

Interaction

Mechanism

Management

Ketoconazole

Decreased bioavailability

Give antacids more than 2 hours after ketoconazole
Efficacy of this not established

Quinidine

Increased serum quinidine
Possible toxicity

Monitor serum quinidine during antacid therapy

Quinolones (ciprofloxacin, norfloxacin)

Decreased absorption

Give antacids at least 6 hours before or 2 hours after quinolones

Iron salts (oral)

Decreased absorption

Separate administration times.

Iron Salts Interact With:

Interaction

Mechanism

Management

Chloramphenicol

Decreased iron clearance

Choose another antimicrobial.
Monitor iron levels.

Levodopa

Decreased absorption

Separate administration times.
Increase dose of levodopa if clinical response is decreased.

Penicillamine

Decreased absorption

Take penicillamine on an empty stomach, unaccompanied by iron preparations

Quinolones

Decreased absorption

Avoid co-administration

Thyroid hormones

Decreased effect of levothyroxine

Separate administration
Monitor thyroid function

Tetracyclines

Decreased absorption of both agents

Avoid co-administration
Separate by 3 to 4 hours

Bismuth Salts Interact With:

Interaction

Mechanism

Management

Tetracyclines

Decreased serum levels

Avoid simultaneous administration.
Give bismuth salts 2 hours after tetracyclines

Urinary Alkalizers Interact With:

Interaction

Mechanism

Management

Tetracyclines

Increased excretion

Separate use by 3 to 4 hours.
Increased dose of tetracycline may be necessary.

Sympathomimetics (pseudoephedrine)

Decreased elimination of ephedrine and pseudoephedrine

Decrease dose of sympathomimetics

Sulfonureas (chlorpropamide)

Increased elimination of chlorpropamide

Dose may need to be increased. Monitor blood glucose levels during co-administration.

Salicylates

Increased renal clearance
Decreased effect

Concurrent therapy may require increased salicylate dose.

Lithium

Decreased lithium plasma levels

AVOID!
Watch for OTC antacids containing sodium bicarbonate

Anorexients

Prolonged effects of Amphetamines.

Avoid agents which may alkalinize the urine.

Digoxin Interacts With:

Interaction

Mechanism

Management

Kaolin-pectin
antidiarrheals
Antacids containing aluminum or magnesium
Large quantities of dietary fibre, including bulk-forming laxatives
Laxatives containing magnesium
Lubricant laxatives such as mineral oil
Charcoal

Physical adsorption of digoxin

Separate doses by 2 hours or more.

Mineral Oil Interactions

Mineral oil is a lipid solvent which may absorb drugs. With chronic use there is "fast" movement of food and drugs through the GI tract so there is not enough time for nutrients and drugs to be absorbed. The fat soluble vitamins A,D,E and K are affected. Vitamins should be given several hours before the mineral oil . Decreased Vitamin K absorption will increase the anticoagulant effect of coumadin. Use of mineral oil should be limited to less than 1 week.
Oral contraceptives can also be affected by absorption of estrogens by the mineral oil. This is only important with chronic use.
Mineral oil given at bedtime can cause lipid pneumonia, especially in elderly, pediatric, debilitated or dysphagia patients.

Other Interactions

Digoxin, salicylates, and nitrofurantoin are bound by cellulose containing products and their absorption is decreased. Psyllium products will bind coumadin. Leave at least 2 hours between doses.
Kaolin-pectin and attapulgite preparations can bind other drugs (especially digoxin and lincomycin). They should be given 2 hours before or 3 to 4 hours after the therapeutic agent to avoid adsorption.













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