Drug Dosing Management
Drug Dosing for Management of Acute Pulmonary Exacerbations
Many adult patients with cystic fibrosis (CF) are colonized with Pseudomonas aeruginosa. S aureus is also frequently present. A minority of patients grow Burkholderia cepacia. Other organisms that are occasionally seen include: Stenotrophomonas maltophilia and Achromobacter xylosoxidans, non-tuberculous mycobacterium, and Aspergillus.
Patients with CF pulmonary exacerbations may be admitted for 2-3 weeks for IV antibiotics. Treatment of pulmonary infection due to either P aeruginosa or B cepacia requires the use of two antibiotics. Antibiotics are selected based on previous response to therapy, sputum cultures, and known antibiotic intolerances or allergies. Doses of antibiotics are higher in patients with CF because they have altered pharmacokinetics.
Drug | Dosing | Notes |
---|---|---|
IV Antibiotics |
||
Amikacin# |
30mg/kg/day IV divided q8h |
Monitor levels to adjust dose* |
Aztreonam |
2g IV q6h |
Special Access (Health Canada) |
Cefipime |
2g IV q8h |
Non-formulary at SPH Maximum 6-8 g/day |
Ceftazidime | 2g IV q6h (or 3g IV q8h for home IV) |
Maximum 8-12 g/day |
Ceftriaxone |
2g IV q12h |
|
Chloramphenicol |
50-100mg/kg IV divided q6h |
|
Ciprofloxacin |
400 mg IV q8h |
|
Colymycin |
5-8 mg/kg/day IV divided q8h |
Maximum 480 mg/day |
Cotrimoxazole (TMP/SMX) |
20mg/kg/day IV divided q6h |
Dosed on TMP, serious infection dosing |
Imipenem |
1g IV q6h |
|
Meropenem |
2g IV q8h |
Preferred carbapenem |
Piperacillin/Tazobactam |
4.5g IV q4h |
Maximum 18-24 g piperacillin/day |
Ticarcillin/clavulanate |
3.1g IV q4h or 6.2g IV q6h |
Maximum 24-30 g ticarcillin/day |
Tobramycin# |
10 mg/kg IV once daily 12mg/kg/day IV divided q8h |
Monitor levels to adjust dose* |
Vancomycin |
See dosing guidelines on PHC Connect: “Vancomycin – How to Prescribe” |
Monitor levels to adjust dose* |
PO Antibiotics (outpatients) |
||
Cephalexin |
1 g PO QID |
|
Cloxacillin |
2 g PO QID |
|
Cotrimoxazole (TMP/SMX) |
2 DS (double-strength) tabs PO BID |
|
Ciprofloxacin |
750 mg PO TID |
≤40 kg: 750 mg PO BID |
Doxycycline |
200 mg PO daily |
|
Levofloxacin |
750mg PO daily |
|
Linezolid |
600 mg PO BID |
Requires Special Authority |
Minocycline |
100mg PO BID |
*Levels: | Peak (mg/L) | Trough (mg/L) |
---|---|---|
Amikacin | 25-30 | < 10 |
Tobramycin once daily | 20-30 | < 1 |
Tobramycin conventional | 10-12 | < 2 |
Vancomycin | n/a | 15-20 |
# Most CF patients admitted to SPH have previous treatments with aminoglycosides. Doses would have been adjusted to their pharmacokinetics. Thus when they are admitted, we try to start them on the dose used in the previous admission (ie. empiric dosing is not used).