EXAM- Antimicrobials Flashcards
Cara has comes into your clinic. You diagnose her with community acquired pneumonia. What pathogens commonly cause this? Are they gram + or negative?
S. pneumoniae (gram +)
Mycoplasma pneumoniae (atypical)
Chlamydophila pnuemoniae (atypical)
(per bugs and drugs, ppt slides)
What would you prescribe for Cara’s pneumonia, which is mild and does not require hospital admission? She denies any previous medical history. Not on any medications. Not pregnant. Allergy to PCN.
Describe any teaching you would provide with this medication
Doxycycline 200mg PO once, then 100mg po bid for 5 days.
Expect clinical improvement in 48-72 hours.
Contraindicated in pregnancy and breastfeeding.
AE- GI irritation (n,v,d, abdo pain), photosensitivity.
Can cause hepatotoxicity or super infection
Absorption inhibited by food and antacids.
Finish full course even if you start to feel better
Cara calls you after a day. She says she can’t take the antibiotics anymore because she is puking her guts out. What do you do?
Can switch to alternative therapy
Azithromycin 500 mg po daily x 3 days
Caution- cytochrome p450 inhibitor- can increase concentrations of other drugs. Not a concern in this pt.
Chelsea is a 2o year old student living in residence at University. She comes to you with a productive cough and fever. You diagnose her with pneumonia and collect a sputum culture for her before starting antibiotics. She has no medical history or allergies. What do you prescribe?
Amoxicillin 1g PO tid x 5 days
Chelsea’s cultures come back positive for mycoplasma pneumoniae two days into her course of antibiotics. Are you happy with her completing her course of amoxicillin?
No. Amoxicillin does not have coverage against mycoplasma pneumoniae (bugs and drugs). I would switch her to doxycycline (excellent activity against most CAP pathogens, including atypicals).
Doxycycline 200mg po once, then 100mg po bid x 5 days.
(CI in pregnancy, breast feeding. AE- frequent GI; also phosensitivity, superinfection, hepetotoxicity). Do not administer with antacids. Many DIs).
Note- I discovered that you can also search bugs and drugs by culture directed infection (in case Susan asks about a specific organism on the exam)
Paul presents to your clinic with 3 days of increasing pain and swelling to his underarm. You discover a skin abscess surrounded by red, slightly raised tissue that is warm to touch. Paul tells you he had a similar infection last year on his shin after a wrestling tournament. No fever or systemic symptoms. Paul has no allergies and isn’t on any medication. Aside from frequent skin infections, he is otherwise healthy. What do you do?
Likely I &D- abscess with surrounding cellulitis.
Rx- cephalexin 500mh po qid x 5 days PLUS TMP/SMX 1 DS tab po BID x 5 days
Rationale: bugs and drugs, skin abscess + cellulitis (mild) PLUS suspicious/ has risk factors for MRSA (frequent skin infections, wrestling= contact sport).
Cephalexin- first gen cephalosporin (broad spectrum, beta lactam, renal elimination, low toxicity/ rare adverse effects). Take w food to reduce GI upset. RxFiles p. 85
TMP/ SMX- antifolate agents (inhibit consecutive steps of folate synthesis to inhibit bacterial DNA/ RNA synthesis). SMX metabolized in liver, both excreted by kidney, reduce dose in renal impairment. NOTE TMP/SMX is not safe in pregnancy (not an issue for Paul) and pts must be encouraged to drink lots of water with SMX (low solubility can cause aggregates and kidney damage if dehydrated). Can cause n/v, headaches, blood dyscrasias, photosensitivty, many drug interactions. p. 87 rx files.
Right before he leaves your clinic, Paul casually mentions that he thinks he might also have chlamydia because one of his partners contacted him last week to let him know they were diagnosed with chlamydia. He says “Oh, this should work out fine though, because I’m on two other antibiotics!”.
Do the antibiotics you have prescribed for Paul cover chlamydia?
Cephalexin- no/ insufficient activity against chlamydia species.
TMP/ SMX- unknown
Where to check?? Bugs and drugs > antibiotics > antimicrobial spectrum of activity> antimicrobials.
So, what to do with Paul now? Does he need to be treated for chlamydia even if he hasn’t tested positive himself?
Yes. All partners in last 6o days (regardless of s/s) should be tested and treated with one of the recommended regimens. He should be counselled to abstain from sexual activity for 7 days after initiation of treatment and avoid exposure to untreated partners.
Recommended regimen: Doxycycline 100mg PO bid x 7 days OR Azithromycin 1g po in a single dose ( BCCDC Guidelines for STI posted on brightspace by Susan)
If you recall, we are also treating Paul for his armpit skin infection. Going back to bugs and drugs for this, we see that we initially chose cephalexin + TMP/ SMX (for MRSA coverage). HOWEVER, we could choose doxycycline instead of TMP/SMX, and this would also provide treatment for the chlamydia.
So, I would send him home with Cephalexin 500m po QID + doxycycline 100mh po bid x 7 days.
This is likely more complex than what Susan wants us to do, but I thought it was good practice for using different resources and figuring out how to navigate them,
You see 19 year old Jenna in your clinic for suspected gonorrhea infection. Her pregnancy test was negative today, and she has no drug allergies. What do you do?
-CT/GC NAAT plus culture for gonorrhea
-Assess for possible PID
-Cefixime 800mg PO (single dose) PLUS Azithromycin 1g PO (single dose) (covers gonorrhea and chlamydia) (BCCDC guideline p. 3)
-Reportable STI
-Contact all partners in last 60 days for treatment
-Counselling- abstain from sexual activity for 7 days after initiation of therapy and avoid exposure to untreated partners
-Recommend repeat screening in 6 mo
Stacy is a 35 year old, non pregnant female who comes in to see you for dysuria, urgency, and frequency x3 days. No fever, chills, abdo, or flank pain. Her UA shows pyuria. What are the most likely pathogens? What do you do?
Ensure UC collected and sent.
Most likely pathogens- e.coli, s. saprophyticus, enterobacteria
Nitrofurantoin 100mg po bid x5 days
Broad spectrum, uncomplicated cystitis. Short term use well tolerated, may cause n/d/d/ d. rare- pulm rcn, hematologic, neuropathy, hepatotoxicity. Avoid in dec renal fcn. p.120, 121 rx files.
Jeremy is a 55 yo male with dysuria, urgency, frequency x3 days. No hematuria. No fever. No abdo or flank pain. UA shows pyuria. What will you prescribe him?
Cefixime 400mg po daily x 10 days
Bugs and drugs, complicated UTI/ males (UTIs are typically considered complicated as functional or anatomical abnormalities are present. EXCEPTION= makes with first time UTI rt sexual activity).
Urologic work up recommended in males with recurrent cystitis, pyelonephritis, and all young boys.
Derek is a 44 quadraplegic man with an indwelling catheter. Experiencing vague suprapubic tenderness and cloudy urine. No fever. What to do?
Change catheter, urine spec obtained through new cath.
Cefixime 400mg po daily x 10 days
Education: prevention (optimal hydration, hand hygiene).
Derek develops a fever, increased spasticity, and general malaise. Other VSS. A & 0 x3. What to do?
For febrile, systemically unwell CAUTI, ampicillin 1-2g IV q6h PLUS ceftriaxone 1-2g IV daily x7-10 days (to the hospital we go!)
