Question

The physician orders: 1. Theophylline (theostat) 65 mg per NG QID for a 3 y/o child weighing 9.9 kg. Safe dose 22mg/kg/day Q 6 hours. Stock Bottle labeled 80 mg/15 ml. Calculate the amount nceded. Is the dose safe? Dade is too high 2. Ceftazidime (tazicef or fortaz) 280 mg IV q8h in 10 ml D5/1/3 NS for a 4 y/o child weighing 17 kg. 280 0-4 wks: 30 mg/kg/day IV Q 12 hours. 1 mo-12 y/o: 30-50 mg/kg/day Q 8 hours; not to exceed 6 Gm/day. Safe dose: 15 Timing 50 mg/ml IV over 30 minutes. Stock = 1 Gm vial of powder. Directions Dilute with 10 ml sterile water for injection to make 95 mg/ml. Stable in the refrigerator for 7 days. Calculate the amount needed. Is the dose safe? 17g

Answer 1

ANSWER.

* Calculation of amount of drug required.

       Formula = Desired dose/Dose in hand * Quantity.

         Here

              Desired dose (D) = 65 mg.

              Dose in hand (H) = 80 mg.

                 Quantity(Q) = 15 ml.

     As per formula

           Amount of drug required = D/H * Q

                                                   = 65/80 * 15

                                                   = 0.81 * 15

                                                   = 12.15 ml.

     * Safe dose = 22 mg/kg/day Q 6 hours.

        Weight of the patient = 9.9 kg.

        Safe dose for a patient with 9.9 kg = 22 * 9.9

                                                                = 217.8 mg/day/Q6hr(QID).

       * Ordered dose(65 mg) is safe for this child.

2) Calculation of the amount of drug required.

          Formula = Desired dose/Dose in hand * Quantity.

        Here

             Desired dose(D) = 280 mg.

             Dose in hand (H) = 95 mg.

                  Quantity(Q) = 1 ml.

As per formula

    Amount of drug required = D/H * Q

                                            = 280/95 * 1

                                           = 2.94 ml.

* Safe dose = 30-50mg/kg/day Q 8 hr(4yr old child).

   Patient weight = 17 kg.

Safe dose for a patient with 17 kg = 30*17 - 50*17

                                                         = 510 mg - 850mg/day/Q8hr.

    *Ordered dose(280mg) is safe for this child.