JN is a 33 year-old (dosing weight 84.1  kg) male who presents to the ER with a history of being bitten by a dog in the jaw 3 days ago. As a vet, the patient empirically started himself on amoxiclav BID. He now presents with a red, swollen mandible that is painful and warm to the touch. He also complains of fever and chills that started last night. He has no significant past medical history other than a documented severe allergy to cephalosporins. You are rounding with the infectious disease consultants and recommend starting clindamycin and gentamycin (170 mg IV Q8H) for antibiotic coverage.

Overnight, the patient’s status changed drastically. Due to unstable blood pressure and respiratory distress, he is transferred to the ICU. Cultures reveal gram (-) rods in the blood. Gentamicin serum concentration drawn around the 3^rd dose were:

4.2 mg/L (level taken at 0900 hr)

0.57 mg/L (level taken at 0725 hr)

Gentamicin doses were given by intermittent IV fusion from 0800 to 0830

1) What is the elimination rate t1/2 in this patient in h (provide to 3 significant figures)? 

2) What is the gentamicin volume of distribution in L (provide to 3 significant figures) 

3) What is the gentamicin clearance, in L/h (provide to 3 significant figures) 

4) The desired target peak is 9 mg/L (30 minutes after the end of the 30 minute infusion). What dose should be given every 8 hours to achieve the target peak? Round the dose to the nearest 5 mg. 

5) The target trough should be no more than 1 mg/L. With your new dose, will the trough be less than 1 mg/L.

No

Yes

Answer rating: 100% (QA)

1 The elimination rate t12 in this patient in h is 32 h To calculate this we need to use the formula t12 0693K where K is the elimination rate constan... View the full answer