Antimicrobial Stewardship (AMS)

Resources to help you ensure the safe and effective use of antimicrobials in NSHA patients.

Guidelines for Antimicrobial Use

About the Stoplight System

The Stoplight Formulary System was designed to preserve certain antimicrobials and/or provide alerts for adverse effects. YELLOW and RED antimicrobials are covered on this page.

For safety of antimicrobials in pregnancy/breastfeeding or for appropriate use and dosing in pediatrics please refer to the IWK Spectrum app. This is available for free for iPhone and Android devices

Colour Coded Formulary

Protected Antimicrobials

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations.
GREEN No restrictions.
Drug Protection Status
Acyclovir GREEN
Amikacin YELLOW
Amoxicillin GREEN
Amoxicillin/ Clavulanate YELLOW
Amphotericin B deoxycholate YELLOW
Amphotericin B liposomal (Ambisome) YELLOW
Ampicillin GREEN
Azithromycin YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Caspofungin YELLOW
Cefazolin GREEN
Cefepime RED
Cefixime YELLOW
Cefotaxime YELLOW
Cefoxitin YELLOW
Cefprozil GREEN
Ceftazidime YELLOW
Ceftolozane-Tazobactam RED
Ceftriaxone YELLOW
Cefuroxime GREEN
Cephalexin YELLOW
Cidofovir YELLOW
Ciprofloxacin YELLOW
Clarithromycin YELLOW
Clindamycin YELLOW
Cloxacillin GREEN
Colistin YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Dapsone YELLOW
Daptomycin RED

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations.
GREEN No restrictions.
Drug Protection Status
Ertapenem YELLOW
Ethambutol GREEN
Erythromycin YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Fidaxomicin RED
Fluconazole GREEN
Fosfomycin YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Ganciclovir YELLOW
Gentamicin YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Imipenem-Cilastatin RED
Isoniazid GREEN

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Letermovir RED
Levofloxacin YELLOW
Linezolid RED

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations.
GREEN No restrictions.
Drug Protection Status
Meropenem YELLOW
Metronidazole GREEN
Minocycline GREEN

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations.
GREEN No restrictions.
Drug Protection Status
Neomycin YELLOW
Nitrofurantoin GREEN
Nystatin GREEN

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Oseltamivir YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Pen G GREEN
Pen V GREEN
Pentamidine YELLOW
Piperacillin/Tazobactam YELLOW
Pyrazinamide GREEN
Pyrimethamine YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Rifabutin GREEN
Rifampin GREEN

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours. 
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations. 
GREEN No restrictions.
Drug Protection Status
Tetracycline GREEN
Tigecycline RED
Tobramycin YELLOW
Trimethoprim YELLOW
Trimethoprim/Sulphamethoxazole YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Protection Status

RED Protected antimicrobial. Requires AMS review within 72 hours.
YELLOW Protected antimicrobial. Defined criteria for use and/or important safety considerations.
GREEN No restrictions.
Drug Protection Status
Valacyclovir GREEN
Valganciclovir YELLOW
Vancomycin YELLOW
Voriconazole YELLOW

Spectrum of Activity - the listed microorganisms are expected coverage based on intrinsic properties of each antimicrobial. For specific sensitivities in your area, please see your local antibiograms.

Therapeutic Interchanges

Interchanges provide a therapeutically equivalent alternative to non-formulary antimicrobials or address common dosing issues that arise. These interchanges will expedite and simplify clarifications.

The tables listed here are recommended for NSHA. All other previous systemic antimicrobial interchanges will be eliminated. The dosing recommendations below are for adults.

For pediatrics, please refer to IWK Spectrum app or other resource.

Antimicrobial Order Interchange
Cefazolin 1 g IV any frequency Cefazolin 2 g IV same frequency
Cefazolin __g IV q6h Cefazolin 2g IV q8h
Cefazolin 500mg PO q6h Cephalexin 500mg PO q6h
Cefoxitin 1g IV q6-8h  Cefazolin 2g IV q8h and metronidazole 500 mg IV q12h
Exceptions: Pelvic inflammatory disease (PID), post partum x 1
dose for 3rd or 4th degree tears, and surgical prophylaxis for
gynecologic procedures. 
Cefoxitin 2g IV q6-8h  Cefazolin 2 g IV q8h and metronidazole 500 mg IV q12h
Exceptions: Pelvic inflammatory disease (PID), post partum x 1
dose for 3rd or 4th degree tears, and surgical prophylaxis for
gynecologic procedures. 
Ceftriaxone (Rocephin®) 1 g IV
q12h or 2 g IV q24h
Ceftriaxone 1 g IV q24h
Exceptions: meningitis or CNS infections, necrotizing fasciitis,
periorbital/orbital cellulitis, osteomyelitis, joint infections,
typhoid, Lyme disease and endocarditis. 
Ciprofloxacin 400 mg tablet  Ciprofloxacin 500 mg tablet
Ciprofloxacin 500 mg IV  Ciprofloxacin 400 mg IV
Ciprofloxacin extended release
(Cipro® XL) PO
Ciprofloxacin regular release product, same dose PO (daily dose
divided and given twice daily)
Clindamycin _ mg IV q 6h 

Clindamycin _ mg IV q 8h (total daily dosage no more than 1800
mg), Exception: Gynecology patients being treated for PID,
necrotizing fasciitis, and toxic shock syndrome may receive 900
mg IV q8h

Cloxacillin IV any dose q4-6 hours Cloxacillin 2g IV q4h

Interchanges provide a therapeutically equivalent alternative to non-formulary antimicrobials or address common dosing issues that arise. These interchanges will expedite and simplify clarifications.

The tables listed here are recommended for NSHA. All other previous systemic antimicrobial interchanges will be eliminated. The dosing recommendations below are for adults.

For pediatrics, please refer to IWK Spectrum app or other resource.

Antimicrobial Order Interchange
Erythromycin IV (all regimens) Azithromycin 500 mg IV daily
Exception: erythromycin IV used as motility agent
Erythromycins, oral: Base (enteric/particle -coated tab) 250mg Erythromycins, oral - Base (conventional release)
Erythromycins, oral: Estolate tablets 250mg Erythromycins, oral: Stearate tablets 250mg
Erythromycins, oral: Ethylsuccinate tablets 400mg Erythromycins, oral: Base Tablet 250mg

Interchanges provide a therapeutically equivalent alternative to non-formulary antimicrobials or address common dosing issues that arise. These interchanges will expedite and simplify clarifications.

The tables listed here are recommended for NSHA. All other previous systemic antimicrobial interchanges will be eliminated. The dosing recommendations below are for adults.

For pediatrics, please refer to IWK Spectrum app or other resource.

Antimicrobial Order Interchange
Meropenem 1g or 2g* IV q8h Meropenem 500 mg IV q6h *Dose is not interchanged if treating CNS, cystic fibrosis, or endophthalmitis infections
Metronidazole _ mg IV q 6-8h Metronidazole _ mg IV q12h (Exception: Clostridium difficile infection, subdural empyema or brain abscess)
Metronidazole 250 mg PO/IV q12h  Metronidazole 500 mg PO/IV q12h
Micafungin Caspofungin 70mg IV on day 1 , followed by 50mg IV q24h (exception endocarditis)

Interchanges provide a therapeutically equivalent alternative to non-formulary antimicrobials or address common dosing issues that arise. These interchanges will expedite and simplify clarifications.

The tables listed here are recommended for NSHA. All other previous systemic antimicrobial interchanges will be eliminated. The dosing recommendations below are for adults.

For pediatrics, please refer to IWK Spectrum app or other resource.

Antimicrobial Order Interchange
Nitrofurantoin regular as follows:
50 mg PO bid
50 mg PO qid
Nitrofurantoin Macrocrystals (Macrobid®):
100 mg PO daily
100 mg PO bid
Exceptions include: Tube and crushing administration, patients with gut absorption issues i.e. ileostomy, short gut syndrome
Nystatin oral suspension 100,000 units/mL, doses written for 1mL, any frequency/schedule Nystatin oral suspension 500,000 units (5mL) same frequency/schedule-if no frequency written will be dispensed as 5mL QID for 10 days
Exception – Palliative Care

Interchanges provide a therapeutically equivalent alternative to non-formulary antimicrobials or address common dosing issues that arise. These interchanges will expedite and simplify clarifications.

The tables listed here are recommended for NSHA. All other previous systemic antimicrobial interchanges will be eliminated. The dosing recommendations below are for adults.

For pediatrics, please refer to IWK Spectrum app or other resource.

Antimicrobial Order Interchange
Penicillins
- Penicillin G 500 000 IU (300 mg) oral
- Penicillin G IV
- Penicillin G potassium IV
- Penicillin V potassium 250 mg
(400 000 IU)
- Penicillin V potassium 500 mg
- Penicillin V 300 mg
Penicillins
- Penicillin V potassium 300 mg oral
- Penicillin G sodium IV
- Penicillin G sodium IV
- Penicillin V potassium 300 mg
(500 000 IU)
- Penicillin V potassium 600 mg
- Penicillin V potassium 300 mg