Pharmacology Mnemonics - Flash Cards

Name: Vitamin B₁₂ (Cyanocobalamin)

Class:

Mechanism: Necessary for folate Metabolismolism and DNA synth. Maintains myelinization of spinal cord tracts.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility:

Special Features: Vegan diet ® deficiency ® megaloblastic pernicious anemia and degeneration of posterolateral spinal cord tracts. If patient is deficient in B₁₂ and folate, replace B_12­ first to avoid irreversible neuro damage. Liver damage ® ­ need.

Name: Biotin

Class:

Mechanism: Incorporated in coenzyme A.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility:

Special Features: Some antibiotics kill gut microbes that synthesize biotin.

Name: Vitamin B₃ (Niacin)

Class:

Mechanism: Incorporated into NAD and NADP.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility:

Special Features: Deficiency ® pellagra (dementia, dermatitis, diarrhea). Penicillamine, hydralazine, and isoniazid complex w/B₆ ® ¯ B₆. B₆ is a cofactor of tryptophan ® nicotinic acid conversion. Results in ¯ B₃.

Name: Vitamin B₆ (Pyridoxine)

Class:

Mechanism: Derivatives serve as coenzymes in many intermed. rxns.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s: Megadose—severe (often irreversible) sensory neuropathy

Utility:

Special Features: Deficiency ® cheilosis, glossitis, dermatitis, peripheral neuropathy. Liver damage ® ­ need. Penicillamine, hydralazine, and isoniazid complex w/B₆ ® ¯ B₆. B₆ is a cofactor of tryptophan ® nicotinic acid conversion. Results in ¯ B₃. Pregnancy ® ­ B₆ demand.

Name: Vitamin B₁ (Thiamine)

Class:

Mechanism: Coenzyme in decarboxylation rxns. Facilitates conduction of impulses in peripheral nerves.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility:

Special Features: Deficiency ® dry & wet beriberi, Wernicke-Korsakoff’s synd. RDA directly proportional to caloric intake. Deficiency common in alcoholics.

Name: Vitamin B₂ (Riboflavin)

Class:

Mechanism: Converted to coenzymes FMN and FAD.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility:

Special Features: Deficiency ® ariboflavinosis, cheilosis, stomatitis, glossitis, dermatitis, corneal vascularization.

Name: Vitamin K

Class:

Mechanism: Cofactor in hepatic carboxylation of procoagulants—factors II, VII, IX, and X.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Antagonize coumarin anticoagulation (min. dose = 60-100 x RDA). Infants given injxn (infant GI tract lacks microbes that produce vitamin K).

Special Features: Deficiency ® bleeding diathesis. Some antibiotics kill gut microbes that synthesize vitamin K. Bishydroxycoumarin antagonizes effects of vitamin K. Prolonged use of large dose salicylates block vitamin K actions in prothrombin synth. ® hypoprothrombinemia.

Name: Dihydrotachysterol (Hytakerol, DHT)

Class: Vitamin

Mechanism: Increases intestinal absorption of calcium and phosphate. Stimulates bone resorption by facilitating effects of PTH. Stimulates renal reabsorption of calcium and phosphate. Net result = ­­ calcium, ­­ phosphate.

Absorption: Oral usu ® adequate absorption. Bile is essential for absorption.

Dist.: Stored in fat and muscle. Tightly bound to vitamin D-binding protein.

Metabolism.: Requires hydroxylation in liver for full activity.

Excretion, t½: 1° = bile.

Toxicity/S.E.s: Excess accumulation in fat/muscle, hypervitaminosis D, hypercalcemia. Drug interactions—phenytoin and phenobarbital reduce sensitivity to vit. D and/or increase rate of inactivation of calcitriol.

Utility: Treat X-linked hypophosphatemic rickets (+ phosphate salts). Treat renal osteodystrophy 2° to chronic renal disease. Treat hypoparathyroidism (+ calcium).

Special Features: Does not require kidney activation. Liver hydroxylation produces full activity. ¼ the price of calcitriol, but takes 1-2 wk. to increase serum calcium. Serum concentration not measurable.

Name: Calcitriol/1,25-(OH)₂-cholecalciferol (Rocaltrol)

Class: Vitamin

Mechanism: Increases intestinal absorption of calcium and phosphate. Stimulates bone resorption by facilitating effects of PTH. Stimulates renal reabsorption of calcium and phosphate. Net result = ­­ calcium, ­­ phosphate.

Absorpt.: Oral usu ® adequate absorption. Bile essential for absorpt. Parenteral.

Dist.: Stored in fat and muscle. Tightly bound to vitamin D-binding protein.

Metabolism.:

Excretion, t½: 1° = bile. Hours.

Toxicity/S.E.s: Excess accumulation in fat/muscle, hypervitaminosis D, hypercalcemia. Drug interactions—phenytoin and phenobarbital reduce sensitivity to vit. D and/or increase rate of inactivation of calcitriol.

Utility: Vit. D Metabolism. of choice for rapid action. Raises serum calcium in 1-2 d. Treat X-linked hypophosphatemic rickets (0.25-1 mg/d + phosphate salts). Treat renal osteodystrophy 2° to chronic renal disease. Ameliorates Type I vit. D-dependent rickets (0.25-0.5 mg/d). Treat hypoparathyroidism (+ calcium).

Special Features: Does not require liver or kidney activation (fully activated).

Name: Calcifediol/25-OH-cholecalciferol

Class: Vitamin

Mechanism: Increases intestinal absorption of calcium and phosphate. Stimulates bone resorption by facilitating effects of PTH. Stimulates renal reabsorption of calcium and phosphate. Net result = ­­ calcium, ­­ phosphate.

Absorption: Oral usu ® adequate absorption. Bile is essential for absorption.

Dist.: Stored in fat and muscle. Tightly bound to vitamin D-binding protein.

Metabolism.: Requires hydroxylation in kidney for full activity.

Excretion, t½: 1° = bile. Weeks.

Toxicity/S.E.s: Excess accumulation in fat/muscle, hypervitaminosis D, hypercalcemia. Drug interactions—phenytoin and phenobarbital reduce sensitivity to vit. D and/or increase rate of inactivation of calcitriol.

Utility: Treat osteomalacia 2° to liver disease. Treat renal osteodystrophy 2° to chronic renal disease—50-100 mg/d (larger dose necessary because kidney hydroxylation is deficient).

Special Features: Does not require liver activation. Fully activated in kidney. More effective than calcitriol for increasing renal absorption of calcium and phosphate. Much less effective than calcitriol for increasing bone resorption and increasing intestinal reabsorption of calcium and phosphate.

Name: Vitamin D₃/cholecalciferol (Delta-D)

Class: Vitamin

Mechanism: Increases intestinal absorption of calcium and phosphate. Stimulates bone resorption by facilitating effects of PTH. Stimulates renal reabsorption of calcium and phosphate. Net result = ­­ calcium, ­­ phosphate.

Absorption: Oral usu ® adequate absorption. Bile is essential for absorption.

Dist.: Stored in fat and muscle. Tightly bound to vitamin D-binding protein.

Metabolism.: Requires hydroxylation in liver and kidney for full activity.

Excretion, t½: 1° = bile. Weeks.

Toxicity/S.E.s: Excess accumulation in fat/muscle, hypervitaminosis D, hypercalcemia. Drug interactions—phenytoin and phenobarbital reduce sensitivity to vit. D and/or increase rate of inactivation of calcitriol.

Utility: Treat nutritional rickets—prophylactic dose = 400 U/d, fully developed rickets = 3,000-4,000 U/d. Ameliorates Type I vit. D-dependent rickets (4,000 U/d). Treat osteodystrophy 2° to malabsorption of vit. D and calcium—25-50,000 U 3x/wk + calcium. Supplement to estrogen and calcium to treat postmenopausal osteoporosis. Treat hypoparathyroidism (25-100,000 U 3x/wk + oral calcium); use calcitriol or dihydrotachysterol for faster action or if hypervit. D develops.

Special Features:

Name: Vitamin D₂/ergocalciferol (Deltalin, Drisdol, Calciferol)

Class: Vitamin

Mechanism: Increases intestinal absorption of calcium and phosphate. Stimulates bone resorption by facilitating effects of PTH. Stimulates renal reabsorption of calcium and phosphate. Net result = ­­ calcium, ­­ phosphate.

Absorption: Oral usu ® adequate absorption. Bile is essential for absorption.

Dist.: Stored in fat and muscle. Tightly bound to vitamin D-binding protein.

Metabolism.: Requires hydroxylation in liver and kidney for full activity.

Excretion, t½: 1° = bile. Weeks.

Toxicity/S.E.s: Excess accumulation in fat/muscle, hypervitaminosis D, hypercalcemia. Drug interactions—phenytoin and phenobarbital reduce sensitivity to vit. D and/or increase rate of inactivation of calcitriol.

Utility: Treat nutritional rickets; prophylactic dose = 400 U/d, fully developed rickets = 3,000-4,000 U/d. Ameliorates Type I vit. D-dependent rickets (4,000 U/d). Supplement to estrogen and calcium to treat postmenopausal osteoporosis. Treat hypoparathyroidism (25-100,000 U 3x/wk + oral calcium); use calcitriol or dihydrotachysterol for faster action or if hypervit. D develops.