Antibiotics - Respiratory

CAP CURB 0-1

Infection	Community acquired pneumonia CURB score 0-1
Most likely organisms	S. pneumoniae
Empiric treatment	If no recent antibiotics: Amoxicillin 500mg q8h po. If recent antibiotics: Co-amoxiclav 625mg q8h po or Clarithromycin 500mg q12h po or Doxycycline 200mg stat then 100mg q12h po.
In penicillin allergy	Clarithromycin 500mg q12h po or Doxycycline 200mg stat then 100mg q12h po.
Duration	7 days.
Comments	Risk of aspiration: add Metronidazole 400mg q8h po (not necessary with co-amoxiclav). * Clarithromycin can cause significant increases in INR. For patients on Warfarin and Clarithromycin, INR must be monitored very closely and appropriate Warfarin dose adjustments made as necessary.

CAP CURB 2-3

Infection	Community acquired pneumonia CURB score 2-3
Most likely organisms	S. pneumoniae Atypical organisms
Empiric treatment	Co-amoxiclav 1.2g q8h iv plus Clarithromycin 500mg q12h po. If recent co-amoxiclav use: Cefuroxime 1.5g q8h iv plus Clarithromycin 500mg q12h iv/po. Oral stepdown: Co-amoxiclav 625mg q8h po plus Clarithromycin 500mg q12h po.
In penicillin allergy	Hx of rash with penicillin: Cefuroxime 1.5g q8h iv plus Clarithromycin 500mg q12h po. Oral stepdown: Doxycycline 200mg stat then 100mg q12h po. Severe penicillin allergy: Levofloxacin 500mg q12h po/iv.
Duration	7 days. Legionella pneumophila, atypical, S. aureus or gram negative pneumonia need 14-21 days treatment.
Comments	Risk of aspiration: add Metronidazole 500mg q8h iv / 400mg q8h po (not necessary with co-amoxiclav). Choice of agent should depend on antibiotic Hx. Consider agent from a different class to recent antibiotic course. If unresolving clinical picture or Legionella pneumophilia, atypical S. aureus or gram negative pneumonia consult Micro/ID/Resp. medicine. Switch to oral therapy when apyrexial and clinical parameters improving. * Clarithromycin can cause significant increases in INR. For patients on Warfarin and Clarithromycin, INR must be monitored very closely and appropriate Warfarin dose adjustments made as necessary. ** Moxifloxacin: Is contraindicated in clinically relevant heart failure with reduced left ventricular ejection fraction, in bradycardia, where there is a history of QT prolongation or history of symptomatic arrhythmias. Moxifloxacin should not be used concurrently with other drugs that prolong the QT interval, e.g. amiodarone, sotalol, neuroleptics e.g. haloperidol, chlorpromazine. Seek advice from pharmacy. It is also contraindicated in patients with impaired liver function (Child Pugh C). There are ongoing concerns regarding hepatic and serious skin reactions with moxifloxacin. Only use when there is no other alternative. More on switching IV to PO.

CAP CURB 4-5

Infection	Community acquired pneumonia CURB score 4-5
Most likely organisms	S. pneumoniae
Empiric treatment	Ceftriaxone 2g q24h iv plus Clarithromycin 500mg q12h iv. Oral stepdown: Co-amoxiclav 625mg q8h po plus Clarithromycin 500mg q12h po. Switch to oral therapy when apyrexial and clinical parameters improving.
In penicillin allergy	Ciprofloxacin* 400mg q12h iv / 500-750mg q12h po plus Vancomycin 25mg/kg (max 2g) loading dose then 15mg/kg q12h iv. Penicillin allergy or on Micro/ID/Resp. advice: Levofloxacin 500mg q12h po/iv.
Duration	7- 10 days Legionella pneumophila, atypical, S. aureus or gram negative pneumonia may need 14-21 days treatment.
Comments	Consider pneumococcal and legionella urinary antigen test after consult with Resp./Micro/ID. Risk of aspiration: add Metronidazole 500mg q8h iv / 400mg q8h po. If no clinical improvement after 48- 72 hours, consider MRSA cover and seek advice from Micro./ID/Resp. Medicine. If Vancomycin used: maintain pre-dose levels 15-20mg/L.* Clarithromycin can cause significant increases in INR. For patients on Warfarin and Clarithromycin, INR must be monitored very closely and appropriate Warfarin dose adjustments made as necessary. Moxifloxacin is contraindicated in clinically relevant heart failure with reduced left ventricular ejection fraction, in bradycardia, where there is a history of QT prolongation or history of symptomatic arrythmias. Moxifloxacin should not be used concurrently with other drugs that prolong the QT interval, e.g. amiodarone, sotalol, neuroleptics e.g. haloperidol, chlorpromazine. Seek advice from pharmacy. It is also contraindicated in patients with impaired liver function (Child Pugh C). There are ongoing concerns regarding hepatic and serious skin reactions with Moxifloxacin. Only use when there is no other alternative. MUH/SIVUH Co-amoxiclav 1.2g q8h iv plus** Clarithromycin* 500mg q12h po. If recent co-amoxiclav use: Cefuroxime 1.5g q8h iv plus Clarithromycin* 500mg q12h iv/po. Oral stepdown: Co-amoxiclav 625mg q8h po plus Clarithromycin* 500mg q12h po. More on switching IV to PO.

Pneumonia - Healthcare associated

Infection	Healthcare assoc. pneumonia (Inpatient <72 hrs)
Most likely organisms	S. pneumoniae
Empiric treatment	Follow community acquired pneumonia guidelines
In penicillin allergy	Follow community acquired pneumonia guidelines
Duration
Comments	Follow community acquired pneumonia guidelines.

Pneumonia - ventilator associated

Infection	Late Healthcare / ventilator assoc. pneumonia
Most likely organisms	Gram negative organisms, S. aureus
Empiric treatment	Late healthcare associated pneumonia Vancomycin 25mg/kg loading dose then maintenance 15mg/kg q12h (max dose 2g) plus Ciprofloxacin 400mg q8-12h iv, 500-750mg q12h po. If septic / septic shock: add Gentamicin 5mg/kg od iv (max 480mg).If MRSA pneumonia suspected, seek advice from micro./I.D./resp. medicine. Ventilator associated pneumonia: Contact micro. re Pip-Taz.
In penicillin allergy	Ciprofloxacin 400mg q8-12h iv / 750mg q12h po plus Vancomycin 25mg/kg (max 2g) loading dose then 15mg/kg q12h iv plus Gentamicin 5mg/kg q24h (max 480mg) if septic / septic shock, with daily review of need. Risk of aspiration: add Metronidazole 500mg q8h iv / 400mg q8h po.
Duration	7 days if uncomplicated and early clinical improvement, otherwise 10-14 days.
Comments	Discontinue Gentamicin if no resistant pathogens identified after 48-72 hours, and clinical improvement. If no clinical improvement after 48-72 hours, consider MRSA cover and seek advice from Microbiology / ID / Respiratory Medicine. NB: If recent antibiotic use, choose a different class. Tailor therapy according to culture and sensitivities. If Vancomycin used: maintain pre-dose levels 15-20mg/L. Gentamicin dosing. If MUH or SIVUH Piperacillin-tazobactam 4.5g q8-6h iv. If septic / septic shock: add Gentamicin 5mg/kg od iv (max 500mg).If MRSA pneumonia suspected, seek advice from microbiology / ID / respiratory medicine. Healthcare / ventilator assoc. pneumonia = Inpatient >72 hrs, Attended hospital > 2 days within past 90 days, Resident in nursing home / long term care facility, On chronic dialysis, Recent wound care, IV antibiotics or chemotherapy.

COPD / Bronchitis

Infection	COPD / Bronchitis
Most likely organisms	H. influenzae, S. pneumoniae, Moraxella catarrhalis, Mycoplasma pneumonia
Empiric treatment	Co-amoxiclav 1.2g q8h iv or 625mg q8h po.
In penicillin allergy	Clarithromycin 500mg q12h iv/po or Doxycycline 200mg stat then 100mg q12h po.
Duration	7 days.
Comments	Contact Respiratory Medicine if no clinical improvement after 48- 72 hours. If patient on long term Azithromycin, discontinue Azithromycin whilst on antibiotic treatment course and restart when course complete. * Clarithromycin can cause significant increases in INR. For patients on Warfarin and Clarithromycin, INR must be monitored very closely and appropriate Warfarin dose adjustments made as necessary.

Bronchiectasis

Infection	Bronchiectasis
Most likely organisms	Bronchiectasis: refer to Respiratory Medicine.
Empiric treatment	Bronchiectasis: refer to Respiratory Medicine.
In penicillin allergy	As above
Duration
Comments	Bronchiectasis: refer to Respiratory Medicine.

Pleural Infection - Community Acquired

Infection	Pleural infection: Community acquired
Most likely organisms	S. pneumoniae, H. Influenzae, S. aureus anaerobes
Empiric treatment	Co-amoxiclav 1.2g q8h iv plus Metronidazole 400mg q8h po / 500mg q8h iv.
In penicillin allergy	Ciprofloxacin 500-750mg q12h po/ 400mg q8-12h iv plus Vancomycin 25mg/kg (max 2g) loading dose then 15mg/kg q12h iv plus Metronidazole 400mg q8h po/ 500mg q8h iv.
Duration	At least 3 weeks and consult with Resp. Medicine.
Comments	Refer to Respiratory Medicine and review culture results. On clinical improvement, consider oral step-down and consult with Respiratory Medicine regarding choice of antibiotics. If MUH / SIVUH Co-amoxiclav 1.2g q8h iv Or Cefuroxime 1.5g q8h iv Plus Metronidazole 400mg q8h po / 500mg q8h iv. Aim for Vancomycin level 15 - 20 mg/L.

Pleural Infection - Hospital Acquired

Infection	Pleural infection: Hospital acquired
Most likely organisms	Gram ve and -ve organisms, anaerobes.
Empiric treatment	Ciprofloxacin 400mg bd-tds iv, 500-750mg bd po plus Vancomycin 25mg/kg (max 2g) loading dose then 15mg/kg q12h iv strong>plus Metronidazole 500mg q8h iv / 400mg q8h po.
In penicillin allergy	Ciprofloxacin 400mg q8-12h iv/ 500-750mg q12h po plus Vancomycin 25mg/kg (max 2g) loading dose then 15mg/kg q12h iv plus Metronidazole 500mg q8h iv / 400mg q8h po.
Duration	At least 3 weeks and consult with Resp. medicine.
Comments	Refer to Respiratory Medicine and review culture results. On clinical improvement, consider oral step-down and consult with Respiratory Medicine regarding choice of antibiotics. If Vancomycin used: maintain pre-dose levels 15-20mg/L. If MUH / SIVUH Piperacillin-tazobactam 4.5g q8h-q6h iv plus Vancomycin Loading Dose then 15mg/kg q12h iv plus Metronidazole 500mg q8h iv / 400mg q8h po.

Pneumocystis carinii

Infection	Pneumocystis carinii Pneumonia (PCP)
Most likely organisms	Pneumocystis carinii (jiroveci)
Empiric treatment	Co-trimoxazole iv 120mg/kg/day in 3-4 divided doses (i.e. 1920mg q6h iv for a 65 kg patient). Oral step-down: Same dose as iv, (i.e. 1920mg q6h po for a 65 kg patient).
In penicillin allergy	Co-trimoxazole iv 120mg/kg/day in 3-4 divided doses (i.e. 1920mg q6h iv for a 65 kg patient). Oral step-down: Same dose as iv, (i.e. 1920mg q6h po for a 65 kg patient).
Duration	21 days.
Comments	Broncho-alveolar lavage necessary to confirm diagnosis. Always contact Respiratory Medicine / ID if PCP suspected. Contact pharmacy for dosing and administration advice.

Cystic Fibrosis

Infection	Cystic fibrosis exacerbations
Most likely organisms	P. aeruginosa, S. aureus, H. influenzae, B. cepacia
Empiric treatment	Always consult Respiratory Medicine. Choice of antibiotics will depend on patient history.
In penicillin allergy	As above
Duration
Comments	Always consult Respiratory Medicine. Choice of antibiotics will depend on patient history.

Appendices

Appendix 1 Switching from IV to PO therapy
Appendix 2 Aminoglycoside monitoring
Appendix 3 Vancomycin
Appendix 4 Clostridium difficile diarrhoea
Appendix 5 MRSA
Appendix 6 Renal impairment, antibiotics
Appendix 7 IV preparations
Appendix 8 Prescribing Tips
Prophylaxis - Endocarditis
Prophylaxis - Meningitis
Prophylaxis - Post Splenectomy /Hyposplenic
Penicillin Allergy
SEPSIS.

Links

Content By Dr. Íomhar O' Sullivan 10/08/2010. Last review Dr. ÍOS 10/06/17.