Antibiotics COPY Flashcards
What antibiotics are suitable in pregnancy?
Penicillins and Cephalosporins
What are the indications for aminoglycosides?
Used for serious infections
CNS infections e.g meningitis
TB (streptomycin)
Pyelonephritis, pneumonia, endocarditis
What is the therapeutic range for gentamicin?
5-10mg/L
Which aminoglycoside is given orally? and why?
Neomycin- too toxic for IV use
What are the side effects of aminoglycosides? (3)
1) Nephrotoxicity
2) Ototoxicity
3) Peripheral neuropathy
Aminoglycosides shouldn’t be used in…? (2)
1) Myasthenia gravis (impairs neuromuscular transmission)
2) Pregnancy (ear damage)
Aminoglycosides interact with what drugs?
1) Loop diuretics and Vancomycin (ototoxicity)
2) Cisplatin, Ciclosporin and vancomycin (nephrotoxicity)
IV treatment with aminoglycosides should not exceed how many days?
7 days
Monitoring requirements for aminoglycosides? (3)
1) Plasma concentration (18-24 hours after dose)
2) Renal function (especially during periods of dehydration)
3) Auditory and vestibular function
Common bacteria in meningitis? (3)
1) Neisseria meningitidis
2) Streptococcus pneumoniae
3) Haemophilius influenza
Antibiotics used in meningitis?
Benzylpenicillin, cefotaxime, chloramphenicol
Name 8 cephalosporins?
1) Cefalexin
2) Cetrotide
3) Cefaclor
4) Cefuroxime
5) Cefixime
6) Ceftriaxone
7) Ceftaroline
8) Fosamil
Are cephalosporins broad spectrum?
Yes
Indications for cephalosporins?
2nd or 3rd line treatment for UTI and RTI
IV for severe resistant organisms
Pneumonia, meningitis, gonorrhoea
Side effects of cephalosporins? (2)
1) GI effects
2) Penicillin hypersensitivity (avoid in known allergy)
Do IV cephalosporins require approval by a microbiologist?
YES and are now mainly restricted to antibiotic associated colitis
Does warfarin interact with cephalosporins? if so, how?
YES, cephalosporins kill the gut flora responsible for synthesizing vitamin K this results in a reduction in the production of vitamin K dependent blood clotting factors-results in increased anticoagulant effect of warfarin.
What is the first line antibiotic group for MRSA?
Glycopeptides e.g vancomycin, Teicloplanin etc
What indications are glycopeptides generally used for?
MRSA
C.diff
endocarditis
surgical prophylaxis (MRSA risk)
What are the main side effects of glycopeptides? (5)
1) Nephrotoxicity
2) Blood disorders
3) Ototoxicity
4) ‘Red man syndrome’
5) Thrombophlebitis (IV)
When would you avoid using glycopeptides?
elderly, history of deafness, renal impairment, pregnancy (ear damage)
What are the monitoring requirements for glycopeptides? (5)
1) FBC
2) WCC
3) Hepatic and renal function
4) Urinalysis
5) Auditory function in elderly
What drugs do glycopeptides interact with?
Ciclosporin, cisplatin, aminoglycosides, loop diuretics
Suxamethonium- (Increases vancomycin conc)
What are the indications for clindamycin (lincosamide)? (3)
1) Staphylococcal joint and bone infections
2) Intra abdominal sepsis
3) Cellulitis and skin and soft tissue infections (effective against penicillin resistant streptococci)
Important side effects of clindamycin? (4)
1) Antibiotic associated colitis-REPORT diarrhoea
2) Esophageal disorders
3) Jaundice
4) SJS, rash
In what patient groups is clindamycin CI?
Existing diarrhoea
Caution in middle aged/ elderly women after an operation
What are the indications for macrolides?
Respiratory infections (in addition to penicillin), Lyme disease, severe pneumonia (added to penicillin), skin and soft tissue infections (alternative to penicillin)
Important side effects of macrolides? (4)
1) Antibiotic associated colitis
2) QT prolongation
3) Ototoxicity
4) Cholestatic jaundice
Why would you avoid using macrolides in myasthenia gravis?
Macrolides cause electrolyte abnormalities which can aggravate myasthenia gravis
Main CI for macrolides?
1) Hepatic impairment (cholestatic jaundice)
2) Arrhythmia (QT prolongation)
What drugs interact with macrolides?
1) CYP450 substrates
2) Drugs that prolong QT interval
What are the main indications of metronidazole? and appropriate doses? (3)
1) Antibiotic associated colitis (400mg TD 5 days)
2) Oral infections (200mg TD 3 days for gingivitis)
3) Gynecological infections e.g trichomonas vaginal infection
Main side effects associated with metronidazole? (3)
1) Neurological effects e.g peripheral and optic neuropathy
2) Mouth-Taste disturbance, furred tongue and mucositis
3) Hearing loss
Is metronidazole a CYP450 inhibitor?
NO, it is a substrate of CYP450
What happens if you drink alcohol while taking metronidazole?
‘di-sulfram like’ reaction will occur. Metronidazole inhibits the clearing of acetylaldehyde (intermediary metabolite)- this causes flushing, headache, tachycardia
How long after stopping metronidazole should you avoid alcohol?
2 days
What drugs does metronidazole interact with? (4)
1) CYP450 inhibitors
2) CYP450 inducers
3) CYP450 substrates
4) Lithium (reduces clearance of lithium resulting in toxicity)
What effect will ketoconazole have on metronidazole?
Ketoconazole is a CYP450 inhibitor, metronidazole is a substrate of CYP450 therefore ketoconazole will reduce the metabolism of metronidazole. Metronidazole is a pro-drug so this will reduce the efficacy of metronidazole.
What duration of treatment with metronidazole requires FBC and hepatic monitoring?
10 days
Are penicillins broad spectrum?
Yes
What are the main indications for penicillins? (7)
1) Tonsillitis (streptococcal)
2) Otitis media
3) Cellulitis
4) RTI
5) Meningitis
6) Tetanus (C.diff)
7) Skin and soft tissue infections
Main side effects of penicillin’s? (2)
1) Penicillin allergy
2) CNS toxicity (convulsions, coma)-do not give intrathecal injection
Main drug interaction of penicillin’s?
Methotrexate- reduced renal excretion and increased toxicity
What are the main indications for co-amoxiclav? (3)
Main side effect of co-amoxiclav?
1) Pneumonia
2) UTI (250-500mg 8hrly)
3) H.pylori (combo therapy)
Same as penicillin’s + Cholestatic jaundice (no more than 14 days treatment)
What are the main indications for flucloxacillin? (3)
Main side effect of flucloxacillin?
1) Skin and soft tissue infections e.g cellulitis
2) Osteomyelitis/septic arthritis
3) Endocarditis
Same as penicillin’s +Cholestatic jaundice
Name two diaminopyrimidine antibiotics
1) Trimethoprim
2) Co-trimoxazole
How do diaminopyrimidines work?
Bacteriostatic-inhibit folate synthesis
Main indications of diaminopyrimidines?
Uncomplicated UTI (200mg 12 hourly) RTI, pneumocystis pneumonia (co-trimoxazole)
What are the main side effects associated with diaminopyrimidines? (2)
1) Blood disorders (look out for bruising, bleeding, ulcers etc)
2) SJS
What are the main CI for diaminopyrimidines? (2)
1) Pregnancy (Teratogenic-especially in first trimester)
2) Caution in folate deficiency
Drugs that interact with diaminopyrimidines?
K+ elevating drugs e.g ACE inhibitors, ARB’s
Folate antagonists e.g methotrexate
Phenytoin, warfarin (reduced clearance)
Name five Quinolone antibiotics?
1) Ciproflaxacin
2) Monoflaxacin
3) Levofloxacin
4) Ofloxacin
5) Norfloxacin
Why are quinolones typically 2nd and 3rd line drugs?
Rapid resistance developing
Main indications that quinolones are used for? (4)
1) UTI
2) severe GI infections including travelers diarrhoea
3) LRTI
4) Gonorrhoea
What are the main side effects associated with quinolones? (5)
1) C. diff
2) Neurological-seizures and hallucinations
3) Inflammation and rupture of tendons-STOP
4) Prolong QT interval-arrhythmia
5) Photosensitivity
What is an important side effect of monoflaxacin?
Life threatening hepatotoxicity
In what conditions should quinolones be use with caution?
1) Epilepsy
2) GPD6 deficiency
3) Joint disorders e.g myasthenia gravis
4) Children and adolescents (disease of joints)
What drugs do quinolones interact with?
1) Calcium and antacids (reduce absorption)
2) Theophylline (quinolones inhibit CYP450)
3) NSAIDS
4) Prednisolone (tendon rupture)
5) QT prolonging drugs e.g amiodarone, antipsychotics etc
What is the last resort antibiotic for MRSA?
Linezolid (vancomycin resistant cocci)
What types of infections is Linezolid used for?
Complicated skin and soft tissue infections and pneumonia
What type of drug is linezolid (HINT-psychiatric effects)
MAOI
What are the main side effects associated with Linezolid?
1) Bipolar and confusional states
2) History of seizures
3) Uncontrolled hypertension
4) Elderly (increased risk of eosinophilia)
What foods should be avoided while taking linezolid?
Tyramine rich foods
What monitoring is required for Linezolid if the treatment exceeds 14 days?
FBC monitoring unless patient has existing myelosuppression, taking blood drugs and renal impairment (check for eosinophilia)
What monitoring is required for Linezolid if treatment exceeds 28 days?
Check for optic neuropathy
What drugs does Linezolid interact with and why?
SSRIs, triptans, tricylic antidepressants, sympathomimetics, buspirone, opioids, pethidine, antipsychotics (MAOI inhibitor)
Which TWO drugs cause peripheral neuropathy?
Metronidazole and nitrofurantoin
What type of infection is nitrofurantoin used for and what are the typical doses?
1st line for UTI (100mcg m/r BD for 3 days) and as prophylaxis for UTI (50-100mg nightly for max 6 months)
What are the main side effects associated with nitrofurantoin? (4)
1) Dark yellow/ brown urine
2) Pulmonary reactions
3) Peripheral neuropathy
4) Hepatitis
In what patient groups would nitrofurantoin be an inappropriate choice? (2)
1) Pregnancy
2) CI in renal impairment
What are the TWO monitoring requirements for LT nitrofurantoin use?
Hepatic and pulmonary function
In what patient groups would a specimen and culture be collected before treatment for UTI?
Men, pregnant women, children <3, Upper UTI, resistant organism suspected e.g Klebsiella suspected
What are the treatment options for an uncomplicated UTI in a child >3mo?
Trimethoprim, Nitrofurantoin, Cefalexin, amoxicillin
What are the treatment options for an uncomplicated UTI in a child <3mo?
IV ampicillin with gentamicin or cefotaxime in hospital, then oral treatment
What are the antibiotic treatment options for recurrent UTI’s in children?
Trimethoprim or nitrofurantoin
Name FIVE tetracyclines?
Tetracyline, doxycycline, minocycline, lymecyline, oxytetracyline
What are the main indications for tetracylines? (4)
1) Chlamydia and PID
2) Acne
3) LRTI (including COPD)
4) Malaria, lyme disease, rickettsia
Main side effects associated with tetracylines? (5)
1) Photosensitivity
2) Esophageal irritation
3) Hepatotoxicity
4) benign intracranial pressure- headache and visual disturbances-STOP
5) Discoloration of tooth enamel
In what patient groups would you want to avoid tetracylines?
1) Children <12 (binds to teeth)
2) Pregnancy and breastfeeding
Name TWO conditions that require prolonged courses of antibiotics?
TB and osteomyelitis
Antibiotic used to prevent pneumococcal infection in sickle cell disease?
Phenoxymethylpenicillin, if CI then erythromycin
Antibiotic used as prevention for early onset neonatal infection?
Benzylpenicillin (IV)
Name FOUR beta lactam antibiotics?
1) Penicillins
2) Cephalosporins
3) Carbapenems
4) Monobactams
What is the main use for fusidic acid?
narrow spectrum for staph infections, topically on the skin or eye or IV/oral for osteomyelitis and endocarditis
What is the first line treatment for C.diff?
Metronidazole
or vancomycin or fidoxamicin
What can a tobramycin dry powder inhaler be used for?
Pseudomonas lung infection in CF
Name TWO carbapenems?
Imipenem and Meropenem
Name TWO cephalosporins that can be used for CNS infections?
1) Cefotaxime
2) Ceftriaxone
Which cephalosporin has good activity against haemophillus influenza?
Cefaclor
Which cephalosporin should be used in history of hypercalciuria (history of renal stones)?
Ceftriaxone
What is the maximum duration of treatment for fusidic acid?
10 days
What are the specific monitoring requirements for minocycline if the treatment is longer than 6 months?
Monitor every 3 months for hepatotoxicity, pigmentation of the skin and systemic lupus erythromtosus
Name TWO antimycobacterials?
Clofazimine and Dapsone (both used for leprosy)
Name the FOUR antibiotic groups that can be used in lyme disease?
1) Macrolides
2) Amoxicillin
3) Macrolides
Name SEVEN bacteria that can cause UTI?
1) E coli
2) Staph saprophyticus
3) Proteus
4) Klebsiella
5) Pseudomonas aeruginosa
6) Staph epidermidus
7) Enterococcus Faecalis
What is the antibacterial prophylaxis and treatment of choice for animal bites?
Co-amoxiclav (if penicillin allergic- doxycyline + metronidazole for up to 5 days) and give the tetanus jab
What is the treatment for a >50 year old with meningitis?
Cefotaxime or ceftriaxone
AND Amoxicillin or Ampicillin
Consider adding vancomycin (10 days)
How long is the initial phase of TB treatment?
2 months
How long is the second phase of TB treatment?
4 months
What drugs are used in the initial phase of treatment for TB?
Isonazid (300mg OD)
Rifampicin (<50kg=450mg OD, >50kg=600mg OD)
Pyrazinamide (<50kg=1.5g, >50kg=2g OD)
Ethambutol (15mg/kg OD)
What drugs are used in the second phase of treatment for TB?
Isonazid (300mg OD)
Rifampicin (same as initial)
Which TB drugs cause liver toxicity?
Isonazid
Rifampacin
Pyrazinamide
Which TB drugs cause peripheral neuropathy?
Isonazid
Which TB drugs cause occular toxicity?
Ethambutol
What are the monitoring requirements for TB treatment?
Plasma levels e.g ethambutol Urinalysis Visual acuity testing Blood counts Liver and hepatic function Auditory function in the elderly
What is the duration of treatment for extrapulmonary TB?
10 months
What is a specific CI of pyrazinamide?
Acute attack of gout
