Aluminum- and magnesium-based antacids

Aluminum-based antacids cause constipation, and magnesium-based products cause diarrhoea. When combination products are used, diarrhoea tends to predominate as a side effect. Although these are termed 'non-absorbable', a proportion of aluminum and magnesium is absorbed and the potential for toxicity exists, particularly with coexistent renal failure.

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Source: Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate , p. 164

Drugs causing dyspepsia

NSAIDs including aspirin

Corticosteroids

Bisphosphonates

Potassium chloride

Iron

Antibiotics

Calcium channel blockers

Nitrates

Theophylline

Drugs with antimuscarinic effects, e.g. tricyclic antidepressants



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Source: Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate Whittlesea, p. 152.

Acidosis and dopamine

"If you're monitoring a patient receiving dopamine (Intropin) and the dopamine isn't raising his blood pressure as expected, check the patient's pH. A pH level below 7.1, which can happen in severe metabolic acidosis, causes resistance to vasopressor therapy. Correct the pH level and the dopamine may be more effective."


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Source: Expert LPN Guides: Fluids & Electrolytes (2007), p.169.

Challenges to raising potassium level

If you're having difficulty raising a patient's potassium level, reevaluate his fluid and electrolyte status and ask yourself the following questions:

• Is the patient still experiencing diuresis or suffering losses from the GI tract or the skin? If so, he's losing fluid and potassium.

• Is the patient's magnesium level normal or does he need supplementation? Keep in mind that low magnesium levels make it difficult for the kidneys to conserve potassium.

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Source: Expert LPN Guides: Fluids & Electrolytes (2007), p. 91.

Causes of hypokalemia

Shift of potassium to the intracellular compartment

Acute alkalosis

Following correction of metabolic acidosis (e.g., diabetic acidosis)

Hypokalemic periodic paralysis

Insulin administration

Administration of beta 2-agonists

Conditions of catecholamine excess

• Cardiac surgery
• Myocardial infarction
• Delerium tremens

Barbiturate intoxication

Vitamin B12 therapy

Thyrotoxicosis (rare)

Inadequate potassium intake (uncommon because of renal conservation of potassium)

Starvation

Postoperative state without replenishment

Gastrointestinal potassium loss

Diarrhea

Laxative abuse

Villous adenoma of rectum

Vomiting

Fistulas

Renal potassium loss (renal cause of hypokalemia should be sought if the urinary loss of potassium exceeds 20mEq/day)

Osmotic diuresis

Magnesium depletion

Acute leukemia

Antimicrobial agents (such as carbenicillin, gentamicin, amphotericin B)

Cisplatin administration

Renal conditions with metabolic acidosis

• Distal renal tubular acidosis
• Proximal renal tubular acidosis
• Ureterosigmoidostomy
• Administration of acetazolamide

Conditions with metabolic acidosis

• Cushing's syndrome
• Exogenous corticosteriod administration
• Primary aldosteronism
• Licorice usage
• Renovascular hypertension
• Malignant hypertension
• Renin-producing renal tumor
• Diuretics (thiazides, furosemide)
• Liddle's sydrome
• Bartter's sydrome

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Source: the portable internist by Anthony J. Zollo Jr., MD (1995), p. 328-329.

Metoclopramide and paracetamol

"Metoclopramide increases gastric emptying and increases the absorption rate of paracetamol, an effect which is used to therapeutic advantage in the treatment of migraine."




Source: Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate Whittlesea

Digoxin and drugs that inhibit P-glycoprotein

"Digoxin is a substrate of P-glycoprotein and drugs that inhibit P-glycoprotein, such as verapamil, may increase digoxin bioavailability with the potential for digoxin toxicity (DuBuske 2005)."



Source:Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate Whittlesea

Bisphosphonates and calcium supplements

"Bisphosphonates are often co-prescribed with calcium supplements in the treatment of osteoporosis. If these are taken concomitantly, however, the bioavailability of both is significantly reduced, with the possibility of therapeutic failure."

Source: Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate Whittlesea, p. 42.

Simvastatin and grapefruit juice

"...[Patients] prescribed simvastatin should be advised not to drink grapefruit juice due to the increased risk of statin-induced adverse effects such as myopathy. Grapefruit juice inhibits cytochrome P450 3A4, which is involved in simvastatin's metabolism."

Source: Clinical Pharmacy and Therapeutics, 4th ed. by Roger Walker and Cate Whittlesea, p.40.

Weight gain and drugs for diabetes mellitus

"Unlike the sulfonylureas, insulin, and the thiazolidinediones, [alpha]-glucosidase inhibitors do not cause weight gain."



Source: Modern Pharmacology with Clinical Applications, 5th ed. by Charles R. Craig and Robert E. Stitzel, p. 775.

Mixing Insulin Glargine with other form of insulin

"Because it is necessary to maintain its acidic pH prior to injection, insulin glargine must not be mixed with any other form of insulin during injection."





Source: Modern Pharmacology with Clinical Applications, 5th ed. by Charles R. Craig and Robert E. Stitzel, p. 770.

Metformin and lactic acidosis

"Metformin can cause lactic acidosis, but its occurrence is rare except when renal failure, hypoxemia, or severe congestive heart failure is present or when coadministered with alcohol."

Source: Modern Pharmacology with Clinical Applications, 5th ed. by Charles R. Craig and Robert E. Stitzel, p. 773.