Question

5. The doctor orders 5 ml of phenytoin (Dilantin) q8h po to be given to a toddler who just started having seizures. The child weighs 44 pounds. The Pediatric Reference book states that the safe dose is 5mg/Kg/day. You have a bottle that has liquid phenytoin in it with 6mg per ml. Pt weighs Total mg ordered per dose Total mg/24 safe dose Amount you would administer dosage) Kg. Total mg in 24 hrs ordered . Maximum safe to give every 8 hours ml. (If MD order not safe, calculate based on maximum safe

i dont how to caculate the last question about administering

Answer 1

Answer:

Step 1:

Child weighs 44 pounds.

Child weight in kg

1 kg = 2.2 pound

44 / 2.2 = 20Kg.

Pt weighs 20Kg.

Step 2:

Ordered dose = 5mL of phenytoin q8h

1mL = 6mg

Therefore 5mL contains 5 x 6 = 30mg.

Total mg ordered per dose 30mg

Step 3:

Dose ordered q8h

That means for 24 hrs total of 3 doses ( 8x3 = 24)

For each dose, 30 mg should be administered.

For 24 hrs 30 x 3 = 90mg

Total mg in 24hrs ordered 90mg.

step 4:

Safe dose reads 5mg/kg/day.

Child weighs = 20kg

Safe dose = 5 x 20 = 100mg/day

Total mg/24 safe dose 100mg/day

Step 5:

For 24 hrs = 100mg

For every 8 hours = 100 / 3

= 33.3mg

Maximum safe to give every 8 hours 33.3mg

Step 6:

A physician order is safe dosage which is below than maximum safe dose.

As per physician order, you would administer 5mL(30mg) of phenytoin every 8 hours. A total of 15mL for 24 hrs.

Maximum dose = Desired dose / Dose on hand X Quantity

Desired dose = 30mg ( refer step 2).

Dose on hand = 6mg

Quantity = 1mL

Safe dose = 30 / 6 x 1

= 5mL.

Amount you will administer 5mL.

For additional information

As per maximum safe dosage administer 5.5mL for every 8 hr. A total of 16.5mL for 24 hours.

Desired dose = 33.3 mg (refer step 5)

Dose on hand = 6mg

Quantity = 1mL

Maximum safe dose = 33.3 / 6 x 1

= 5.5mL