Name Date Period. West Nomogram

Transcription

1 West Nomogram A West Nomogram is used to help adjust medication calculations for children. Because children are smaller than adults, they are usually given smaller amounts of medication. The adjustment of the medication dosage is based on the child s size, a combination of height and weight (which can be measured directly), or body surface area (BSA). To calculate a child s BSA, draw a straight line from the height (in the left-hand column) to the weight (in the right-hand column). The point at which the line intersects the surface area (SA) column is the BSA (measured in square meters m 2 ). If the child is of roughly normal proportion, BSA can be calculated by weight alone using the enclosed column. The West Nomogram below shows the BSA of a child who is 40 inches tall and weighs 36.5 pounds. Her BSA is 0.69 m 2. Catch the Fever 2007 ConnectEd: The California Center for College and Career Catch the Fever 68

2 Dosage Calculations Pharmacists have to make lots of calculations every day. They must be very accurate when they calculate how much medication to give every patient they see. A small mistake could mean the difference between helping a patient and harming one. Pretend that you are a pharmacist. For each prescription below, calculate how much medication should be given to each patient. Show your work. 1. A doctor orders 600 milligrams (mg) of Potassium Chloride for a patient taking diuretics. Tablets available contain 300 mg per tablet. How many tablets should be given? 2. A physician orders 250 mg of Sulfasalazine for a patient with rheumatoid arthritis. Tablets available contain 500 mg per tablet. How many tablets should be given? 3. A physician orders 15 mg of Prednisone for a patient with an inflammatory joint disease. Tablets available contain 10 mg per tablet. How many tablets should be given? 4. A physician orders 10 mg of Nembutal elixir to treat a patient with insomnia. It is available as 20 mg in 5ml. How many ml should be given? 5. A physician orders 20 mg of Phenobarbitol elixir for a patient with seizures caused by meningitis. It is available as 30 mg per 7.5 ml. How many ml should be given? Catch the Fever 2007 ConnectEd: The California Center for College and Career Catch the Fever 69

3 Pediatric Dosage Calculations For adults, the physician uses the dosage recommended by the pharmaceutical company that makes the medication. Correct medication dosages for infants and children are based on weight, height, body surface area, and age. It is extremely important to calculate the dosage accurately. A minor error in calculating a dosage for an infant or child can be extremely serious, causing an overdose or even death. Pretend that you are a pediatrician who has to prescribe medication for the following patients. Show all your work. 1. An infant who weighs 10 kilograms (kg) is very sick with a respiratory infection. The correct medication is Vantin. The average adult dose is 500 mg every 12 hours. How much medication should you prescribe for this infant? 2. Acetaminophen has a safe dosage range of 10 to 15 mg/kg, every 4 hours. Your patient is a 1-yearold infant who weighs 12 kg. What is the maximum dose this child could receive? 3. The average adult dose for Wellcovorin is 20 mg. A 15-year-old boy with colon cancer is 5 feet 6 inches tall, but weighs only 115 pounds. How much Wellcovorin should you prescribe? 4. Minoxidil is used to help children with hypertension or high blood pressure. A 9-year-old child with hypertension weighs 15 kg. The drug manufacturer recommends a dose of 0.2 mg/kg/day. How much Minoxidil should you prescribe? Catch the Fever 2007 ConnectEd: The California Center for College and Career Catch the Fever 70

4 Additional Problems Sample: Ordered: Potassium Chloride 20 meq added to the IV Available: 40 meq per 10cc How much Potassium Chloride will you add? D = 20 meq H = 40 meq Q = 10 cc 20 meq 10 cc = X 40 meq = X = 5 cc 1. Ordered: Trilafon 24 mg po bid Available: Trilafon concentrate labeled 16 mg/5 ml 2. Ordered: SoluMedrol 100 mg IM q8h Available: Vial 1 ml in size labeled 125 mg SoluMedrol/3 ml 3. Ordered: Ampicillin 400 mg IM q6h Available: Vial with powder. Label reads: For IM injection, add 3.5 ml Diluent (read accompanying circular). Resulting solution contains 250 mg Ampicillin per ml. Use solution within 1 hour. 4. The physician orders Lasix 20 mg IV stat for a child weighing 34 lbs. The Pediatric Drug Handbook states that 1 mg/kg is a safe initial dose. Should you give this dose? 5. A child with a BSA of 0.32 M 2 has an order for 25 mg of a drug with an average adult dose of 60 mg. Calculate the child s dosage. Is the physician s order correct? 6. Ordered: D5W 50 ml with 20 meq KCl to infuse at 8 meq KCl/hr per IV pump. How many ml of solution will you administer per hour? Catch the Fever 2007 ConnectEd: The California Center for College and Career Catch the Fever 71

5 7. Ordered: 600,000 units of Penicillin po q6h Available: 400,000 units per scored tablet. How many tablets will you administer? 8. The child has a BSA of 0.67 m 2. The adult dose is 40 mg. The physician ordered 8 mg. Is the dosage correct? 9. A child weighing 76 lbs. is ordered to receive 150 mg of Clindamycin q6h. The Pediatric Drug Handbook states the recommended dose is 8 20 mg/kg/day in four divided doses. Clindamycin is supplied in 100 mg scored tablets. What is the child s weight in kilograms (1 kg = 2.2 lbs)? What is the safe recommended daily dose? Is the dose the doctor prescribed within the safe range? How many tablets are needed to give the ordered dose? Catch the Fever 2007 ConnectEd: The California Center for College and Career Catch the Fever 72