troubleshooting the antibiotic prescription

Troubleshooting the Antibiotic Prescription

Dr. LA Sulz (BSP, PharmD)Pharmacists’ Association of Saskatchewan Annual ConferenceRegina, Sask.April 26, 2015

Troubleshooting the Antibiotic Prescription - L Sulz (April 26, 2015)

2 Presentation Overview

Why it’s important to optimize use of antimicrobials

Optimize antimicrobial use to ensure efficacy while minimizing resistance development in common community-acquired infections

Identify management strategies to prevent, or minimize clinically significant drug interactions with common antimicrobials


3 Consequences of Antimicrobial Resistance At least 2 million Americans fall ill from antibiotic-resistant bacteria

every year; at least 23,000 die (CDC Sept 2013) 1/9 patients admitted to hospital each year (250,000 Canadians)

develop hospital acquired infections; 8,000 die (Health Canada) Greater than the number of fatalities from traffic accidents, AIDS and

breast cancer combined Many are resistant to available antibiotics

Compounding the problem, infections are acquired in other health care settings, such as LTCFs & increasingly the community at large

http://www.cihr-irs .gc.ca/e/40485.html accessed Oct 20/13


4 Contributors to Antimicrobial Resistance Unnecessary antibiotic use

11 million kilograms prescribed/year in the U.S. 1.1 million kg (Canada)

75% for respiratory tract infections over 30% not needed

More than $1.1 billion spent annually on unnecessary prescriptions for adult respiratory infections (U.S.) $110 million (Canada)

Improper use (e.g. too long, wrong dose) Lack of rapid diagnostics


5 Antimicrobial Resistance

Antibiotics promote resistance by killing susceptible organisms so resistant organisms have a survival advantage and can be passed on to other people Studies of changing prescribing patterns to improve resistance

patterns has been shown in the community setting in regards to S. pneumoniae resistance

Resistance patterns do not always respond to prescribing changes Proactive approach is best – i.e. Use antimicrobials only when

indicated


6 Combating Antimicrobial Resistance Shorter Duration - Longer not necessarily

better! Community-acquired pneumonia (CAP) 3d vs 8d Cellulitis 5d vs 10d Cystitis 3d vs 7 – 10d Acute pyelonephritis 7d vs 14d

Higher doses - Generally safe (with exceptions)


7 Antibiotics carry other risks! 1 in 4 chance of diarrhea... 1 in 50 chance of a skin reaction... 1 in 1000 chance of an ER visit . .

For comparison, 2 out of 1000 patients will go to the Emergency due to ADR associated with warfarin, insulin, or digoxin

Risk of an ED visit due to an antibiotic (80% due to allergic reactions) is 3X higher than the risk due to antiplatelet agents (e.g., aspirin), oral hypoglycemic agents (e.g., glyburide), and narrow therapeutic window drugs (e.g., anticonvulsants)

Shehab N et al. Clin Infect Dis 2008;47:735-43.Canadian Pharmacist's Letter; April 2012; Vol: 19

1 in 5000 will have an anaphylactic reaction


8 Clostridium difficile Infection

Most frequent cause of healthcare-associated infectious diarrhea in Canadian hospitals

Most common cause of acute infectious diarrheal illness in LTCFs

Strongly associated with previous antibiotic use Antimicrobial stewardship believed to have a

role in preventing and terminating C. difficile infection outbreaks

http://www.phac-aspc.gc.ca/nois-sinp/guide/c-dif-ltc-sld/index-eng.php


9 Antibiotics & Risk of C. difficile Infection Largest risk compared to no antibiotics

Clindamycin - OR 16.8 (7.5 - 37.8) Fluoroquinolones - OR 5.5 (4.3 - 7.1) Cephalosporins, carbapenems - OR 5.7 (2.1 - 15.2)

Lower association with Macrolides - OR 2.6 (1.9 - 3.6) Penicillins -OR 2.7(1.8 - 4.2) Sulfonamides/Trimethoprim - OR 1.8 (1.3 - 2.4)

No effect noted with tetracyclines - OR 0.9 (0.6 - 1.4)

Antimicrobial Agents and Chemotherapy 2013 (57; 5): 2326–32


10 Additional cause for concern:Dwindling antibiotic pipeline

Now, let’s troubleshoot a few cases to see if we can be ‘Antimicrobial Stewards’ to preserve effectiveness of our current antibiotics. . . .


12 Case Patient arrives with a Rx for cephalexin What’s the first thing you do? What might you ask the patient?

What’s the antibiotic for? Patient replies, “I was cleaning up the backyard

and cut my finger on something a couple days ago, and now it’s red, painful and swollen. I think it’s infected.”

What are the most likely causes of skin & soft tissue infections?

Diagnosis – Skin & Soft Tissue Infections (SSTIs) Diagnosis & empirical therapy based on

physical findings and clinical setting Rarely obtain C&S Most cutaneous infections not associated

with bacteremia

13


Prevention - SSTIs

Good hygienic practices; attention to early therapy for superficial processes such as dermatophyte infection Reduces risk for cutaneous & soft tissue infection

Individuals with recurrent cellulitis may benefit from chronic antibiotic suppression 3–4 episodes/year despite attempts to treat or control

predisposing factors (weak, moderate) e.g. oral penicillin , erythromycin b.i.d. for 4–52 weeks, or IM

benzathine penicillin q2–4wks Continued as long as predisposing factors persist (strong,

moderate)

14



Common Community SSTIs Impetigo

A superficial crusting, and at times, bullous infection of the skin Localized progression into the dermis leads to ecthyma crusting skin infection

caused by pyogenic streptococci, similar to impetigo, but extends more fully into the epidermis

Folliculitis A localized infection of hair follicles, which can extend into subcutaneous tissue,

resulting in furuncles May coalesce, leading to carbuncle formation which are typically larger and

deeper than furuncles Most commonly on the back of the neck, especially in individuals with diabetes

Furuncles often rupture and drain spontaneously or following treatment with moist heat

Most large furuncles, all carbuncles should be treated with incision and drainage

Systemic antimicrobials usually unnecessary, unless fever or other evidence of systemic

15


16 Case – Cellulitis Vast majority from streptococci, often group A (GAS, S. pyogenes),

but also from groups B, C, F, or G Staphylococcus aureus less frequently causes cellulitis

associated with open wound, previous penetrating trauma, including sites of illicit drug injection

What are the antibiotic options? Cloxacillin?

Covers Staph > Strep Staph more likely if abscess/pus

No need for renal dose adjustment TMP-SMX?

No ! Poor GAS coverage Suitable antibiotics for most include:

Penicillin, Amoxicillin, Cloxacillin, Cephalexin, Clindamycin 5 days as effective as10 days if clinical improvement by day 5


17 10 Point Antimicrobial Checklist1. Is an antibiotic indicated? preventative, empiric, directive2. Have appropriate specimens been obtained, examined, and cultured?3. What organisms are most likely?4. Which antibiotic is best? 5. Is combination therapy required?6. What are the important host factors?7. What is the best route of administration?8. What is the appropriate dose?9. Will initial therapy require modification?

Consider narrowest spectrum agent; review PK/PD, toxicology, cost, spectrum, and whether important to be bactericidal vs bacteriostatic

10. What is the appropriate duration of therapy? Is resistance going to be a problem?


18 5 – Point Antimicrobial Checklist

1. Is an antibiotic indicated? Preventative, empiric, or directive?

2. Appropriate specimens obtained? Most likely organism(s)?

3. Which antibiotic is best? Is combination therapy required? What is the appropriate duration of therapy?

4. Are there important host factors present? Allergies, renal function, immune status, elderly, debilitated, etc. What is the appropriate dose?

5. Will therapy require modification?

Another case to troubleshoot . . .


20 Case

Patient comes into your Pharmacy with a Rx for amoxicillin

He indicates having a very sore throat with very painful swallowing and trouble eating

How do you proceed?


21 Case

What’s the likely indication? ”strep throat”? How might you confirm this?

1. Is an antibiotic indicated?2. Appropriate specimens obtained?

Ask if throat swab done; if so, check e-health if negative, NO antibiotic indicated


22 Case - Upper Respiratory Tract Infection (Acute pharyngitis, “Strep throat”)

Upper RTIs more common than lower RTIs (bronchitis > pneumonia), and . . . Primarily due to viruses ! !

Large majority self-limiting Supportive care only offer appropriate

doses of analgesics, antipyretics


23 Case – Diagnosis of Acute Pharyngitis Presence of 4 centor criteria:

History of fever Tonsillar exudates No cough Tender anterior cervical lymphadenopathy

(lymphadenitis)

Do not treat if none, or only 1 criteria


24 Case – Diagnosis Acute Pharyngitis3. Which antibiotic is best?

What organisms are most likely? After viruses, most common bacterial cause is Group A beta

hemolytic streptococcus (GABHS) Limit antibiotics to those with the highest likelihood of

GABHS (4 centor criteria) GABHS is 100% susceptible to penicillin

85% to clindamycin, erythromycin -- local (RQHR) antibiogram Cephalexin (1st gen ceph) if not anaphylactic allergy to penicillin Macrolide (erythro, clarithro, azithromycin) if true penicillin

allergy Fluoroquinolone or other broad spectrum agent (amox/clav)

NOT required


25 Case – Diagnosis Acute Pharyngitis4. What are the important host factors?

?Immune status, corticosteroid use, elderly . . . .

?Renal function (check e-GFR) Pen V 300mg po QID

Pt has Rx for amoxicillin which would be acceptable Usually x10 days (5 days if azithromycin)

5. Will initial therapy require modification? If GABHS Symptoms improve dramatically

within 1 - 2days! (If not, unlikely bacterial)


26

What if another patient comes in with Rx for amoxicillin. . . But, it’s for a ‘ head cold’, runny noseHe sounds like he has nasal congestion and says he coughs, especially at night


27 URTI Rhinosinusitis/Acute Bacterial Sinusitis Common problem with 1 / 7 U.S. adults each year1,2

Translates to 2.6 million cases in Canada yearly3 Acute bacterial sinusitis 200 times less common than viral Resolves without antibiotics in majority of cases

Symptoms less than 7 days - unlikely to have a bacterial infection

Consider antibiotics if: Persistent signs/symptoms for 10 days without any evidence of clinical

improvement, or severe symptoms such as fever of 39ºC or higher plus Purulent nasal discharge, maxillary facial/tooth pain, swelling, or tenderness for

3 to 4 days (when unilateral regardless of duration of illness or facial pain) If cold symptoms for 5 to 6 days, got better, now worse

1. Chow AW, et. al. IDSA guideline Clin Infect Dis 2012;54:e72-e112. 2. Rosenfeld RM. Clinical practice guideline on adult sinusitis. Otolaryngol Head Neck Surg 2007;137:365-

77. 3. Desrosiers M, et al. Canadian clinical practice guidelines. J Otolaryngol Head Neck Surg 2011;40(Suppl

2):S99-193.


28 Rhinosinusitis/Acute Bacterial Sinusitis All patients, supportive measures...fluids, analgesics

(ibuprofen, etc), nasal irrigation If it is bacterial S. pneumoniae, H. influenzae Amoxicillin/clavulanate for empiric tx adults &

children RQHR antibiogram: 40% H. influenzae resistant to

amoxicillin alone Reminder: If using high doses for intermediate resistant

S. pneumonaie, must combine with amoxicillin to not ‘overdose’ clavulanate causing significant diarrhea

So, amoxicillin, not an optimal choice in this case


29 Bronchitis -‘Acute Cough Illness’ Greater than 90% Non-bacterial Coughs associated with bronchitis often prolonged:

45% will have a cough at 2 weeks 25% still have a cough at 3 weeks

In patients with cough more 3 weeks, CXR warranted in the absence of other known causes FYI - OTC cough suppressants have limited efficacy in relief of

cough due to acute bronchitis (Chest 2006; 129:95S-103S) Routine antibiotic treatment of uncomplicated

bronchitis NOT recommended, regardless of duration of cough

cdc.gov/getsmart/campaign-materials


30 Community-Acquired Pneumonia (CAP)

Uncommon in healthy, non-elderly adults in absence of vital sign abnormalities, or asymmetrical lung sounds

S. pneumoniae accounts for up to 50% of CAP caused by bacteria

Choice of treatment? Doxycycline (S. pneumoniae + atypicals) Clarithromycin/Azithromycin susceptibility S. pneumoniae 2nd generation cephalsporin cefprozil, cefuroxime though

atypicals not covered Reserve FQs for more severe illness, or pts allergic to

alternatives Always AVOID ciprofloxacin as poor gram positive coverage


31 Acute Excerbation COPD Etiology – S. pneumoniae, H. influenzae, M. catarrhalis

NOTE: Don’t require atypical coverage as for CAP so levofloxacin or moxifloxacin not required

Empiric Tx? Amoxicillin/clavulanate, 2nd gen ceph (cefprozil, cefuroxime) Clarithromycin/Azithromycin if true beta-lactam allergy 5 - 7 days usually adequate

Cannot eradicate the bacteria due to damaged lung structure Longer duration only promotes resistance

What about the patient who says. . . . . “I’m allergic to penicillin”


Penicillin Allergic Patients

10 - 15% hospitalized patients report a penicillin allergy Recent literature suggests up to 95% are negative

Must I avoid a cephalosporin? What’s the likelihood of a cross reaction?

1 in 500 (0.2%) patients with non-severe reactions to penicillins Negligible if -ve penicillin skin test 2 in100 (2%) patients who have a positive penicillin skin test will have

an IgE-mediated response Anaphylaxis is rare 1 - 4 per 10,000 administrations

Take a thorough history and enter into computer system for future reference

33

Penicillin/Cephalosporin Cross-Reactivity Patients who’ve reacted to penicillin; skin testing not available

Low risk if penicillin reaction >10y ago and/or not IgE-mediated reaction (anaphylaxis, urticaria, angioedema, hypotension, bronchospasm, laryngeal edema, pruritis) Give cephalosporin

Moderate risk if reaction <10 years and/or IgE mediated reaction Give cephalosporin by graded challenge start 1/100 cephalosporin full

dose, with ten-fold increasing doses q30-60 minutes until full dose Reaction within 24h may occur in less than 1%, but risk of anaphylaxis is

small

High risk if probable anaphylaxis to penicillin based on history Desensitize to cephalosporin

UpToDate (Sept 30/14)

34



35 IgE Mediated Reactions Type I reactions can be life-threatening Immediate: within 30-60 minutes Delayed: within 1-72 hours Clinical features pruritis, flushing, urticaria, wheezing, angioedema,

hypotension Symptoms typically appear within four hours Urticaria associated with raised red intensely pruritic plaques

Anaphylaxis (most severe form) is rare


36Next case . . .


37 Case

Patient comes into your Pharmacy with a Rx for ciprofloxaxin

What are your next steps? ?Indication

UTI? Causative organism(s)? . . etc, etc.


38 5 – Point Antimicrobial Checklist1. Is an antibiotic indicated?

Preventative, empiric, or directive?2. Appropriate specimens obtained?

Most likely organism(s)?3. Which antibiotic(s)?

Appropriate duration?4. Important host factors present?

Allergies, renal function, immune status, elderly, debilitated, etc.

Appropriate dose?5. Therapy modification? – i.e. Monitoring req’d


39 Urinary Tract Infections (UTIs) Incidence, including urethritis, cystitis, prostatitis, & pyelonephritis

8 - 10 million/year in U.S. 20% (1/5) women symptomatic UTI in lifetime

Many with multiple recurrences (30%) Men much less until 65yo

20-30% of infections reported by long-term care facilities (LTCFs)

cdc.gov/nhsn/PDFs/LTC/LTCF-UTI-protocol_FINAL_8-24-2012.pdf


40

Landry e et al. Urinary Tract Infections: Leading Initiatives in

Selecting Empiric Outpatient Treatment (UTILISE) CJHP Mar–Apr 2014

http://rhdintranet/er/public/Utilise/UTILIZE%20Poster.pdf


41 UTIs First Line Therapy – No EDS/Inexpensive

Nitrofurantoin (Macrobid) 100mg po bid x 5-7d: Rule out systemic infection – i.e. upper UTI, pyelonephritis,

bacteremia limitied/low tissue penetration Check renal function Avoid if Clcr <60mL/min

TMP-SMX 1 DS tablet po q12h If Clcr 15-30mL/min: 1 SS tablet PO q12h Clcr <15mL/min - Avoid If sulfa allergy Trimethoprim 100mg po q12h Possible hyperkalemia if ACEI, ARB, or K+ supplements


42 Second Line Therapy – EDS Required Amoxicillin/Clavulanate (875mg/125mg po q12h, or 500mg/125mg

q8h) unless: True penicillin allergy Anaphylaxis: hives, SOB, throat swelling Known resistant organism (i.e. Pseudomonas on C&S result)

Cefprozil, Cefuroxime (2nd gen cephs) 250mg po q12h (500mg if upper UTI) unless: Severe penicillin allergy Anaphylaxis: hives, SOB, throat swelling or,

cephalosporin allergy Known resistant organism Check C&S result

Beta-lactams (cephalexin, amoxicillin) may be less effective for UTIs


43 Last Resort – EDS Required & Resistant Organisms

Ciprofloxacin 250mg po q12h (500mg if upper UTI) only if: Sulfa and severe beta-lactam allergy Known resistance to all above agents (i.e.

Pseudomonas) Duration?

3 days effective for most; may need longer in elderly due to physiological issues (e.g. prolapsed uterus, prostatitis)


44 Case - UTI What if when you check a recent e-health record, it

indicates urine C&S result as: E. coli resistant to cephalexin, ceftriaxone, ciprofloxacin,

TMP-SMX; only susceptible to gentamicin/tobramycin ESBLs (e.g. E. coli, K. pneumonaie resistant to many broad spectrum

agents such as 3rd gen cephs and ciprofloxacin & other FQs) Often leaves only aminoglycosides, or broad spectrum parenteral

agents How did this patient get such a resistant organism?

?Multiple courses of antibiotics ?Long-term urinary catheter

What do you do?


45 Case - UTI Consider Fosfomycin 3g po x1 dose

Symptoms take longer than a day to disappear Avoid if pyelonephritis suspected

What if no C&S result, but a urinalysis report indicates: +ve Leukocytes -ve Nitrates Bacteria: Scant

If both leukocyte & nitrate test +ve, higher likelihood of bacterial infection, but should confirm with C&S If NO symptoms, Don’t treat!


46 Case

You receive a fax for ciprofloxacin for a resident in the LTCF for which you provide service

What do you do?



Preventative, empiric, or directive? Symptoms?


3. Which antibiotic(s)? Appropriate duration? Check e-health records

4. Important host factors present? Allergies, renal function, immune status, elderly, debilitated, etc. ?catheterized; how long? Appropriate dose? Check renal clearance Be wary if estimated clearance in elderly or debilitated pt is

>80mL/min as calculation is based on creatinine which may be low in those with low muscle mass

If wt unknown estimate Clcr = (140-age)x 90/Scr (x 0.85 if female)5. Therapy modification? – i.e. Monitor pt for symptom resolution

FYI – No need for repeat C&S to confirm eradication (except in pregnancy)


48 Asymptomatic bacteriuria Significant bacteriuria (>108/L), but absence of symptoms

Common, particularly if 65yo or older Chronically catheterized patients

After 10 - 14days, urine will be smelly, cloudy AND always be +ve If no symptoms, do not treat

If symptoms present, catheter must be removed, or symptoms will return after discontinuation

Treatment depends on clinical setting Usually treat significant bacteriuria (>108 CFU/L) without pyuria (<10 WBCs) in infants

& preschool children ?anatomical or mechanical defects ?renal tissue damage during growth phase

May develop pyelonephritis, if confirmed on successive cultures Bacteriuria persisting 48h after catheter removal


49 Recurrent UTIs Recurrent Symptoms/Relapse

Recurrence within 1 - 2 weeks after treatment; usually same organisms Retreat with previous agent for longer duration

e.g. If used a 3 day regimen, retreat for 7 days; if was 7 day regimen, retreat for 14 days

25% of women At least 2 episodes within 6 months, or 3 or more +ve urine

cultures within 12 months Before starting prophylactic antibiotics, urine C&S 1-2 weeks after

infection to rule out relapse Continuous prophylaxis usually given at bedtime

May give every other night or three nights a week Continue prophylaxis for about 6 to 12 months... up to 5 years in

difficult cases


50 Recurrent UTIs Continuous or post-coital prophylaxis

Nitrofurantoin 50 mg, or cephalexin 250 mg for women who usually get UTIs 24 - 48h after intercourse

Take single antibiotic dose after intercourse Avoid contraceptives with spermicide can cause local irritation and

increase chance of bacterial growth Acute self-treatment for women you trust to understand and

follow the instructions i.e. When they get symptoms, drop off a urine sample at the lab for

culture and start a 3-day course of antibiotics If symptoms are not gone within 48 hours, change to a different

antibiotic Choose an antibiotic for UTI prophylaxis based on tolerance,

resistance patterns, and cost. . . they usually have similar outcomes


51 Recurrent UTIs Don't recommend probiotics...there's no

proof they help prevent UTIs

Don’t use prophylaxis if urologic abnormalities or in asymptomatic elderly Contributes to resistance

Canadian Prescriber's Letter; February 2011; Vol: 18


52 Treatment for UTIs Cranberry juice?

Doesn't TREAT a UTI...but may help PREVENT recurrent infectionsIDSA. 2011 Guideline (Women) - Clinical Practice Guidelines CID 2011:52 (1 March)Canadian Prescriber's Letter; April 2011; Vol: 18 Epp A, et Al. J Obstet Gynaecol Can 2010;32:1082-90

Duration 3 - 5 days for uncomplicated UTIs 7 - 14 days for complicated UTIs

Many elderly patients due to anatomic abnormalities 6 - 12 weeks for men with prostate involvement

Don't screen for, or treat asymptomatic bacteriuria -- There's no benefit...and it increases resistance

Canadian Prescriber's Letter; December 2011; Vol: 18


53 Limit use of FQs for UTIs – Why?? Moxifloxacin doesn't get into the urine Increasing gram –ve resistance

RQHR 15% E. coli resistant to cipro Ciprofloxacin usually works, but can cause

"collateral damage“ by inducing resistant Staph, Pseudomonas, Enterococcus, etc.

FQs associated with C. difficile, MRSA outbreaks & increasing resistant E. coli

Canadian Prescriber's Letter; April 2011; Vol: 18 Epp A, et. Al. J Obstet Gynaecol Can 2010;32:1082-90


54

Let’s troubleshoot this last case . . . .


55 Case 64 yo female presents at your Pharmacy with a Rx for moxifloxacin A review of her medication profile includes the following:

Tiotropium (Spiriva), fluticasone inhaler, salbutamol inhaler for COPD, and warfarin for stroke prevention d/t Afib

What are the possible antibiotic-related problems?


56 Case Aug 1 – INR 1.8

Missed a dose previous week, so cont’d same dose (80mg/wk) with 13mg x1

Aug 8 – INR 1.9 14mg x1, incr 84mg/wk – 12mg/d

Aug 22/13 (Thurs) - INR = 7.2 Aug 17/13, 4 days prior, Rx moxifloxacin x 14 days +

prednisone for AECOPD Informed pt to hold x 3d (Th, F, Sa) & reume warf Sunday at

reduced dose 10mg/d (70mg/wk = 17%); repeat INR on Monday, Au 26

Aug 26 - INR 1.0 Pt held warfarin all 4 days (Th – Sun)


57 Case 47yo female with PE discharged from hospital on stabilized dose

of warfarin 10mg/day Sept 4 INR 3.1 Sept 12 = 2.7 Sept 20 = 5.4 – started herbal med to help thin the blood--

advised AGAINST this, but pt refused. No bleeding Hold 2 doses, decrease warfarin to 5mg/d x 2 days & repeat INR

Sept 24 INR 1.3 (0, 0, 5, 5) – no identified changes; pt refused LMWH; increased back to warfarin 11mg/d

Sept 26 INR = 6.4 (after 2 doses 11mg); will stop herbal med – No warfarin today

Sept 27 INR 7.9 – i.e. cont to rise after 1 held dose What are your thoughts?


58 Case Checked PIP Septra DS x7d Sept 20-26

for UTI 6 days prior to elevated INR Hold x2days and start wafarin 5mg/d

In the meantime very low INRs and pt back on 11mg/d

Oct 31 INR = 5.5 – Septra Rx start 30 (again!)

Patient counselling is imperative!


59 Drug Interactions - Significant Patients on warfarin Suggest alternative antibiotics (e.g. amox/clav,

cephalosporins) May need EDS, but safer, more convenient than increased INR monitoring, dose

adjusting when starting & stopping antibiotics

Suggestions for empirically warfarin: SMX-TMP: 25 - 40% Metronidazole: 25 - 40% Miconazole, Fluconazole, Voriconazole: 25 - 30%

Clarithromycin: 15 – 25% Moxifloxacin: 0 – 25%

Erythromycin: 10 - 15% Ciprofloxacin: 10 – 15% Levofloxacin: 0 – 15%

Bungard, T, Brockelbank, C, CPJ


60 Miscellaneous TipsAntimicrobial Therapy Antibiotics are not innocuous Serious, long-term life-

altering reactions (e.g. CDAD) Do NOT dose cephalexin, cloxacillin, penicillin V b.i.d.

Very short half lives; kills bacteria in TIME-dependent, not concentration-dependent manner

So why do patients get better? Infection likely due to a virus, not bacteria! Suboptimal doses may contribute to development of resistance

Cost/EDS Remember to remind patients, EDS does not mean free


61

Sometimes the best thing you can do for a patient is NOT fill their antibiotic Rx!Remember: Most upper respiratory infections are due to viruses!Use the antibiotic check list for a systematic approach



Preventative, empiric, or directive? Symptoms present?


3. Which antibiotic(s)? Check e-health records for recent C&S results RQHR: Contact Med Microbiologist for assistance in interpretation Appropriate duration?

4. Important host factors present? Allergies, renal function, immune status, elderly, debilitated, etc. ?catheterized; how long? Appropriate dose? Check renal clearance Be wary if estimated clearance in elderly or debilitated pt is

>80mL/min as calculation is based on creatinine which may be low in those with low muscle mass

If wt unknown estimate Clcr = (140-age)x 90/Scr (x 0.85 if female)5. Therapy modification? – i.e. Monitor pt for symptom resolution


63Questions?

troubleshooting the antibiotic prescription

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