Antibiotics And Antivirals Flashcards
Unknown cause sepsis
Flucoxacillin, metronidazole, gentimycin UHL
Meropenem KETS
Resp infections - generalised unknown source how would you manage
Give amoxicillin or co amoxicillin
This targets:
Gram positive bacteria e.g. Strep,staph
Gram negative bacteria: haemophillus, moxarella,
Allergic- give doxycycline or meropenem
Which microbes is amoxicillin effective against
This targets:
Gram positive bacteria e.g. Strep,staph
Gram negative bacteria: haemophillus, moxarella,
Also: helicobacter pylori, escheridia coli, proteus mirabilis, so use in GI inf.
Not effective : klebsilla, pseudomonas, serration, citrobacter, some gram negative aerobes
Mechanism of action of amoxicillin
Penicillin so beta lactam antibiotic
Disrupts cell wall synthesis in peptidoglycan cell walls so mostly effective against gram positive bacteria as rely more on their peptidoglycan cell wall.
Name other beta lactam antibiotics
Cephalosporins
Carbapenem- meropenem, eropenem.
Penicillins
Common causative organisms CAP. And their classification
Streptococcus pneumonia- gram positive cocci
Moxeralla catarhalis - gram neg, cocci
Haemophillus influenzae- gram negative bacilli
Curb 65
CURB C- confused? Ab. Mental state score <8 Urea >7 RR >30 BP <90 or <60 diastolic 65 > age
0-1 low risk manage at home
2 hospital general wards
3+ consider ITU
Management of CAP
Antibiotics - amoxicillin or doxycycline. PO
If 2+score then: add doxycline po and then change to co-amox IV
If 2+ allergic: add meropenem IV and can change doxy to clarithromycin IV
HAP common organisms
Psumodmonas aerunginosa
Kelbsiella pneumoniae
HAP antibiotics
(Co- amoxiclav) not pseudo
Tazocin - pipereracillin with taxobactam
Co- amoxiclav uses against which microorganism
Same as amoxicillin but also for resistant microorgnansims, klebsiella
NOT PSEUDOMONAS
Gram positive aerobes- staph, strep, enterococcus
Gram negatives - haemophillus, e.coli. Moxarella, klebsiella, helicobacter pylori . Also: neisseria gonorrhoea,
Also: anaerobic - bacterioides, fusobacterium, peptostreptococcus.
Mechanism of co- amoxiclav
Amoxicillin- b lactamase inhibitor. Inhibit the binding oriteins that do cross linking in bacterial cell walls Clavurinic acid- b lactamase inhibitor : class 2-5 -can really target gram negatives. But not pseudomonas Irreversible inhibitor of thenlactamases
CI in using co amoxiclav
Penicillin allergy,
Cholestatic jaundice or liver dysfunction
hepatic toxicity is usually reversible but still have caution - don’t use over 14 days
CI amoxicillin
Penicillinin celhalosporin allergy
C diff associated diarrhoea can occur
Can interact with methotrexate
Other antibiotics can interfere with amoxicillin (tetracyclines, macrolides)
Cna reduced effectiveness of OCP and oral antocoagulants
Antibiotics in aspiration pneumonia
Co amoxiclav Po or iv
Or meropenem
Antibiotics for acute COPD with acute lrti
Amoxicillin or co amox
Or doxyclijne
Doxycycline- class and mechanism of action
Broad spectrum tetracycline
Reversible inhibitor of 30s bacterial ribosome . Stops binding of tRNA to ribosome.
Name other classes of antimicrobials targeting ribosomes and which classes they treat
Tetracyclines- doxycycline - stop tRNA binding, work with gram positive, and negative and anaerobes
Aminoglycosides- gentimycin, streptomycin - gram neg. read mRNA abnormally .
Macrolides - erythromycin azithromycin. Gram positive and atypical pneumoniae . Stop mRNA translocation
Doxycline - uses, administration
- LRTI if penicillin allergic, milder skin infections if penicillin allergic,
Drugs of choice for intracellular organisms e.g. chlamydia trachomatus ,Lyme disease, mycoplasma, anthrax, rickettsia - all parasitic and penetrate well,
Administration: oral or iv
Tetracyclines
CI
SE
Bind to calcium e.g. Bones and teeth - so CI in young <8yrs, pregnant and lactating women. –> discoloured teeth
SE: N&V, C. difficile, thrush,idiopathic intercranial hypertension
New tetracycline - tigecycline - use and SE CI
Use: gram +ve -ve inc resistant strains. - skin soft tissue GI
CI - caution in liver
SE: inc LFTs, N&V, potosensitivity
Name some aminoglycosides, Their. Mechanisms of action. And overall sensitivity
Gentimycin, streptomycin, tobramycin, amikacin
Mechanisms: bactericidal antibiotics - strong ones, must give IV,
Bind to 30s ribosome and inhibit tRNA binding and ALSO promote misreading of mRNA
USe: gram negatives and gent/Tobramycin - can target pseudomonas.
Amino glycosides CI and SE
Ottotoxicity - damage 5th cranial nerve
Nephrotoxic - CI in renal failure. - Monitor aminoglycosides levels and serum creatinine
CI myasthenia gravis as impairs NM transmission
Resistance in aminoglycosides
Enzymes produced by the bacteria can inactivate the aminoglycosides
Use of aminoglycosides
Gentimycin
- unknown sepsis. - acute life threatening infection inc. pseudomonas. So use until sensitivities known.
- streptococcal endocarditis with penicillin and vancomycin
Amikacin - newest and has least resistance
Name some macrolides, their main use and mechanisms
Erythromycin, clarithromycin,
Gram positive - like penicillin - use in allergies
Mechansim: taken up by gram positive more than negatives - they bind to 50s sub unit and inhibit translocation
Erythromycin and clarithromycin uses, CI andSE
Oral or IV
Sim to penicillin - Gram positive cocci inc. MRSA, and B lactam resistant strains - so use in penicillin allergies!!
Also used in: mycoplasma pneumoniae and legionnaires
CI - not really
SE/interactions: liver metabolism and p450 inhibitors = accumulation of warfarin and inc. conc of statins (rhabdomyelosis) and calcineurin inhibitors etc.
SE: GI, Choletasis, inc. QT
Skin and bone infections/
Flucoxacillin
Or vancomycin if allergic
SE of penicillins
Rashallergy
NV
C diff
Cholestasis
First. Line antibiotic for c.difficile
Metronidazole oral
Name some anaerobes , and what you could use to treat
C.difficile
Bacterial vaginosis
Intra-abdominal, pelvic oral soft tissue. — enclosed environments
E.coli, staphylococcus, clostridium - use metronidazole
Gram negatives:intra abdo infections , frusobacteroium (abscesses wounds), others causin aspiration pneumonia and soft tissue
Gram positives: clostridium, peptostreptococcus, other types causing pelvic neck and head. Infections.
Side effects and CI f metronidazole
Caution withliver problems
Inhibits warfarin metabolism - p450 inhibitor
Can cause disulfuram like reaction with alcohol
First line therapy UTI
Uncomplicated trimethoprim 3 days
Complicated uti
Trimethoprim (women)
Or Co-amoxiclav - recommended more in men
7 days
Pyelonephritis
Co-amoxiclav pO or IV if NBM
Allergic - ciprofloxacin or meropenem
Use of cephalosporins and name example
Alternatives to penicillins when allergies or resistance
Cefriaxone - meningococcus
Ceftazidime - neutropenic sepsis (broad spec)
Diabetic foot ulcers
Superficial flucoxacillin
Deep metronidazole - anaerobic
Allergic - doxycycline
Use of vancomycin and teicoplanin - mechanism
Complicated gram positives including MRSA
Inhibits peptidoglycan formation - from positive
Use septicaemia or endocarditis with MRSA. Or psydomenranous colitis (c.diff)
SE of teicoplanin and vancomycin
Nephrotoxic - monitor creatinine
Ototoxic
Platelet deficiency
Only IV - not oral
Use and mechansim of carbapenems
B lactam inhibitors but very rewesistant to most b lactamases. Wide spec. Acts against gram negatives and gram positives inc. pseudomonas and MRSA
IV
Meropenem
Ertapenem (not for pseudomonas)
Menigitis
Gram -ve cocci
Give cefriaxone
Use of rifamycin
Mycobacterium
Legionella
Meningococcal prophylaxis
Se and CI with rifamycin
Epatitis Gi Cna effects Myelosu[rssion Red secretions- urine sweat s alive tears
Mechansim or tripmthroprim and co-trimoxazole
Folate synthesis inhibitors
Tb treatment
Rifamycin 4 mths
Isoniazid 4 mths
Pyrazinamide 2 mths
Ethambutol 2 mths
SE of ethambutol
CI optic neuritis - ocular toxicity and colour blindness
Don’t use in young. Kids
Cholecytisis infection, peritonitis, or hepatobilary
Treat like sepsis IV - amoxicillin metronidazole gentimycin (or meropenem if allergic)
Abdominal gastroenteritis or other complaint - not as severe
Ciprofloxacin or cefriaxone
Use of gentimycin
Aminoglycosides
Gram negatives inc. pseudomonas
SE of pyramizadole
CI in gout,
Caution in DM
Hepatotoxic, photosensitivity
Se or isoniazid
Caution in liver disease
Peripheral neuropathy - caution in DM - common
Rare - psychotic episode
Name some cutenous fungal infections
Dermatophytosis
Candidiasis
Malassezia
What is dermatopytosis
Ringworm
Scale and pruitis - itchy
Can be circular
Also skin and blisters between toes
Malassezia
Greasy skin - hypo or hyperpigmented ras - sebrharrhoeic dermatitis (scaling and danddruff)]
RF acne
RF Diagnosis and treatment of superficial fungal infections
Immmunocop. Moist environments. Antibiotics
Diagnsis - clinical.skin scrapings
Treatment: topical -azole e.g. Imisazoles or triadazoles
. Or terbinafine 1-4wks
Topical nystatin (candidiasis )
Name a common anti-fungal for superficial infections
Triazoles
- fluconazole
Candiasis infections - superficial
Nystatin or amphotericin
Polyenes - antifungals
Invasive fungal infections - name som organisms
Candidiasis– immunocomp
Cryptococcosis –> menigitis or pneumonia
Histoplasmosis –> from soil with bat or birt faeces
Blastomycosis
RF for invasive fungal.
RF- infection malignancycritical illness e.g. ITU, transplant surgical - GI perforation, burns immunosuppressed
Investigating serious infections - especially suspected fungal and those with RF
3 blood culture samples 3 different sites, same time/
Microscopy and immunohistocemistry
- consider antigen antibody testing
Managing invasive candidiasis
Repeated tissue cultures
Remove potential source- catheter and sample
Give cocktail of antifungals: triazole e.g. Fluconazole. Ecinocandins (terbinafine) and others
7 types of antiviral s
Think 7 steps
1) inhibit penetration - palivzumab (RSV propylaxis in infants at risk)
2) Inhibit uncoatting’ - rare
3) Integrase inhibitors - prevent integrating into nucleus
3) Replication - inhibit viral DNA polymerase- aciclovir, galciclovir. - herpes.
- antiretrovirals - NRTIs
4) inhibit exit - neuramindase inhbitors - oseltamavir, zanamivir
5) prevent maturation/bodies response
- protease inhibitors - prevent maturation of virus
- - immunomodulators - interferon alpha
Treatment complicated influenza
Oseltamivir
Treating HIV - pharm
2x NRTI backbone - combo of 2 NRTIs e.g. Tenofovir emtricitabine Plus. 1 of: - Protease inhibitor- atazanavir - NNRTI - Integrase inhibitor
Also monitor adherence, LFTs glucose, viral load,
Managing HIV
Pharm
Counselling -
Screen forinfectins and malignancy - co-trimoxaloe prophylaxis
Base lines - CD4 viralload LFTelectrolytes pregnancy resistance
Review medications
Antivirals in hepatitis - hep C
Interferons -modulate hosts response - old and now phased out for Hep C with serotype specific treatments
Hepatitis B treatment
Generally upportive - avoid alcoholimmunise contacts Antivirals with interferon if. High risk of liver disease
Hepatitis A treatment
Supportive avoid alcohol
