Aminoglycosides & other drugs Flashcards
Examples of Aminoglycosides?
- Amikacin
- Gentamicin
- Neomycin
- Streptomycin
- Tobramycin
Which aminoglycosides are active against pseudomonas aeruginosa?
TAG
- Tobramycin
- Amikacin
- Gentamicin
How is Tobramycin administered?
Administered via nebulisation or inhalation
What is pseudomonas aeruginosa?
It can cause pneumonia, infections in the blood etc.
What is streptomycin active against?
Streptomycin is active against mycobacterium tuberculosis and reserved almost entirely for tuberculosis.
In what form must Streptomycin be given in and why?
As an injection because it cannot be absorbed from the gut
What is the preferred aminoglycosides?
Gentamicin because it is used to treat many infections including eye/ear infections, pneumonia etc.
What is the usual dose for aminoglycoside?
Once daily is preferred
Parenteral treatment should never exceed 7 days whenever possible.
What is the contraindication for aminoglycosides?
Myasthenia gravis - causes aminoglycosides to impair neuromuscular transmission.
What are the side effects of Aminoglycosides?
- Ototoxicity
- Nephrotoxicity
- Neurotoxicity
- Risk in pregnancy (auditory nerve damage in infants)
- Skin reactions
- Nausea and vomitting
What are the signs of Ototoxicity?
- Tinnitus or ringing in ears
- Hearing loss
- Dizziness
- Uncoordination in movements
- Vestibular damage
What are the signs of Nephrotoxicity?
- Decreased urine output
- Fluid retention (swelling in legs, ankles or feet)
- Fatigue
- SOB (shortness of breathe)
Which drugs cannot be used alongside Aminoglycosides?
- Loop diuretics
- Cephalosporins, ciclosporin or vancomycin
Can loop diuretics be used alongside with Aminoglycosides and why?
No, because the risk of ototoxicity is increased when used alongside each other
Can cephalosporins, ciclosporin
or vancomycin be used alongside aminoglycosides and why?
No because risk of nephrotoxicity is increase when used alongside each other
What are the monitoring requirements for aminoglycosides?
- Plasma concentration
- Renal function (esp in the elderly) - as they are renally excreted
- Auditory and vestibular function
Serum concentration monitored in patients receiving parental aminoglycosides.
Monitored in elderly, obesity, cystic fibrosis, renal impairment or high dose.
Which individuals need dose adjustments for aminoglycosides?
Patients with renal impairment
What dose adjustments must be made for people with renal impairment taking aminoglycosides?
- Increase dose interval
But if renal impairment is severe - decrease dose
When should blood samples be taken for people on aminoglycosides?
Approximately 1 hour after administration (peak concentration) and just before next dose (trough concentration).
What is peak concentration?
The highest concentration of a drug in the blood after dose is given (1 hr after admin)
What is trough concentration?
The concentration of drug in the blood immediately before the next dose is administered
What must be done if the trough concentration is high?
Increase dose interval
What must be done if the peak concentration is high, within range and below range?
High - Decrease the dose
Within range - maintain dose
Below range - increase dose
What should be the peak and trough concentrations for Aminoglycosides?
For IM or IV use for multiple daily regimens:
- Peak concentration: 5-10mg/L
- Trough concentration: <2mg/L
For multiple daily regimens in endocarditis:
- Peak concentration: 3-5mg/L
- Trough concentration: <1mg/L
Which aminoglycosides can be used in gentamicin-resistant bacteria?
Amikacin
Which aminoglycoside is more stable to enzyme activation than gentamicin?
Amikacin
Which Aminoglycoside are too toxic for parenteral administration?
Neomycin sulfate
What MHRA warning/advice is attached to Aminoglycosides?
Aminoglycosides increase the risk of deafness [ototoxicity] in patients with mitochondrial mutations.
Potential histamine-related adverse drug reactions (like rashes) with some batches - caution with pts on drugs which release histamine (e.g opioids).
What are carbapenems?
Beta lactam antibiotics and they are structurally similar to penicillin and cephalosporins.
They are broad spectrum.
What are examples of Carbapenems?
Ertapenem, Imipenem, Doripenem, Meropenem
What are Imipenem and Meropenem used for?
Used for severe hospital acquired infections like: septicaemia, complicated UTI, Hospital acquired pneumonia (HAP) etc.
What must Imipenem be given with and why?
It must be given with Cilastatin because Imipenem is partially inactivated by kidney enzymes
Do Meropenem, Doripenem and ertapenem need to be given with cilastatin?
No because they are stable in renal enzymes
What are the side effects of Carbapenems?
- Diarrhoea
- Headache
- Nausea
- Vomiting
Cautions for carbapenems?
Caution in pts with sensitivity to beta lactam antibacterials.
What are cephalosporins?
Broad-spectrum antibiotics.
Structurally similar to penicillin.
Examples of 1st Generation Cephalosporins?
- Cefalexin
- Cefadroxil
- Cefradine
What do all 1st generation cephalosporins begin with?
Cefa / Cefra
Except for Cefaclor
Examples of 2nd generation cephalosporins?
- Cefuroxime
- Cefaclor
Examples of 3rd generation Cephalosporins?
- Cefotaxime
- Ceftazidime
- Ceftriaxone
- Cefixime
What do all 3rd generation cephalosporins contain?
The letter ‘T’
How are cephalosporins excreted?
Excreted renally
What are the indications for Cephalosporins?
- Septicaemia
- Pneumonia
- Meningitis
- Biliary tract infections
- Peritonitis
- UTI
Which Cephalosporins can be used to treat infections of the CNS like meningitis?
Two third generations -
Cefotaxime & Ceftriaxone
What are the side effects for Cephalosporins?
- Hypersensitivity – approximately 0.5 – 0.6% of penicillin-sensitive patients are also sensitive to cephalosporins.
SO IF PATIENT IS ALLERGIC TO PENICLLIN, DO NOT GIVE CEPHALOSPORINS!
- Antibiotic associated colitis (mainly presented as diarrhoea)- this is more common in 2nd and 3rd generation cephalosporins
What is the drug action for Vancomycin?
It is a glycopeptide antibacterial.
Bactericidal activity against aerobic and anaerobic for only gram positive bacteria - so narrow spec antibiotic