Medication Update: October 2007
Medication Update is a bi-monthly newsletter of the Pharmacy and Therapeutics Committee for physicians, pharmacists and nurses.
New Formulary Drugs
Hydroxocobalamin (Cyanokit®) injection
Hydroxocobalamin is an injectable form of vitamin B12. It is given I.M. for the treatment of cobalamine metabolism deficit disorders, including methylmalonic acidemia and homocystinuria, as well as pernicious anemia and other B12 deficiencies.
Mycophenolic acid delayed release (Myfortic®) tablet
Myfortic is an enteric coated form of mycophenolic acid used to prevent rejection in solid organ transplant patients. Tablets may not be cut or crushed therefore the dose must be rounded to the nearest tablet size. Use is restricted to patients who have failed the use of CellCept due to GI side effects.
Tamsulosin (Flomax®) capsule
Tamsulosin is alpha-1 antagonist added to formulary added to formulary for the use of patients over 5 years of age with obstructive ureteral stones.
Nicotine (Nicoderm®) transdermal patch
Nicotine transdermal patch is used as a nicotine replacement to aid the cessation of smoking.
Other Formulary Issues
Formula Changes
Formulary monograph updates:
- TPN compatibility chart — additional text has been added to the compatibility chart to provide guidance and assist nursing staff in assessing the risks and benefits when a medication is listed as ‘unknown’ on the chart.
Other:
- Insulin — see info below
New Approach to Insulin Dosing
In the past, insulin sliding scales were the standard method of controlling blood sugars in the hospital. However, sliding scales were developed for regular and NPH insulins. Since emulating the body’s physiologic insulin secretion has become more feasible with the development of long-acting basal and rapid-acting insulins, "sliding scale" terminology is not applicable for those utilizing this regimen. The new insulin standard1 of long-acting basal insulin and rapid-acting bolus insulin allows for patient-specific care and is now available in CIS as an "insulin subcutaneous orderset." This article provides a brief overview of this new dosing approach.
To order this new insulin regimen in CIS, select “insulin subcutaneous orderset.” Built into this orderset is detailed knowledge to order insulin. Most patients’ regimens will consist of 4 orders:
- Long-acting basal insulin
- Rapid-acting insulin for meals
- Rapid-acting insulin for bedtime
- Rapid-acting insulin for snacks
(Note: If a patient is stable on a non-basal bolus home insulin regimen, it may be continued in the hospital.)
The Total Daily Dose (TDD) of insulin is typically 0.5 to 1 unit/kg/DAY for diabetic patients. The long-acting basal insulin requirement is usually 40-50% of the TDD. The rapid-acting bolus insulin doses consist of 2 key components shown in the equation below:
For detailed information regarding the use of the new subcutaneous insulin orderset, please visit the following website: http://www.seattlechildrens.org/health_care_professionals/pdf/
newsletter/insulin_subcutaneous_orderset.pdf
References
- American Diabetes Association (ADA). Standards of medical care in diabetes. VIII. Diabetes care in specific settings. Diabetes Care 2007 Jan;30(Suppl 1):S27-33.
Vitamin D Analogs
Vitamin D is a fat-soluble vitamin that contributes to the maintenance of normal blood levels of calcium and phosphorus. Vitamin D is absorbed in the small intestine and metabolized in two steps. The first hydroxylation of vitamin D takes place in the liver and the second in the kidneys, to produce the active metabolite 1, 25-dihydroxyvitamin D. The active metabolite of vitamin D promotes the active absorption of calcium and phosphorus by the small intestine. Elevating serum calcium and phosphate to sufficient levels allows mineralization of bones. It also promotes renal tubule resorption of phosphate. Vitamin D deficiency will cause several bone diseases including rickets and osteomalacia.
In chronic kidney diseases, the production of 1, 25-dihydroxyvitamin D decreases and results in low calcium levels. When calcium levels decrease, the parathyroid gland increases production and secretion of parathyroid hormone (PTH), which signals the bones to release calcium. Excessive production and secretion of PTH in response to hypocalcemia is called secondary hyperparathyroidism.
Vitamin D and Vitamin D analogs
- Ergocalciferol
- Vitamin D2. Found in plants and yeast. Traditional form of Vitamin D put into foods and vitamin pills. Needs activation by the liver and kidneys.
- Indication and usage: Dietary supplement for D deficiency in people who have functional organs.
- Calcitriol
- The most active form of vitamin D3, 1, 25-dihydroxycholecalceferol, in stimulating intestinal calcium transport. Does not require kidney activation.
- Indication and usage: First line agent for management of secondary hyperparathyroidism in patients with moderate to severe chronic renal failure; management of hypocalcemia in hypoparathyroidism and pseudohypoparathyroidism. Generic products available; inexpensive.
-
Doxercalciferol (Hectorol®)
- Synthetic vitamin D2 which already has a hydroxyl group in the first position of the vitamin D2 molecule. Doxercalciferol is activated by the liver to form 1, 25- dehydroxyvitamin D2. Activation of doxercalciferol does not require the involvement of the kidneys.
- Indication and usage: Second line agent for patients who are unable to take calcitriol due to hypercalcemia and hyperphosphatemia.
-
Paricalcitol (Zemplar™)
- Synthetic vitamin D that retains the vitamin D2 structure which contributes to reduced toxicity such as hypercalcemia while retaining the ability to suppress PTH
- Indication and usage: Prevention and treatment of secondary hyperparathyroidism in patients on chronic renal dialysis; may be given 3 times per week at dialysis clinic to improve patients compliance.
References:
- DeLuca HF and Zierold C. Mechanisms and functions of vitamin D. Nutr Rev 1998; 56:S4-10.
- Van den Berg H. Bioavailability of vitamin D. Eur J Clin Nutr 1997;51 Suppl 1:S76-9.
- Agus, ZS. Metabolism of vitamin D. Up to date online 2006.
- Product information: Hectorol® capsule, doxercalciferol. Genzyme Co., Cambridge, MA, 2006
- Product information: Zemplar® injection, paricalcitol. Abbott Lab. Abbott Park, IL, 2006
- Micromedex Drugdex. www.thomsonhc.com, 2006
Credits
Editors
- Renee Freitag, PharmD
- Eric Harvey, PharmD, MBA, BCPS
P&T Chairs
- Janet Englund, MD
- Eric Harvey, PharmD, MBA, BCPS
Address
Children's Hospital and Regional Medical Center
P&T Committee, R-3409
4800 Sand Point Way NE
PO Box 5371/R-3409
Seattle, WA 98105