Chapter 5 - Infection Flashcards
Patient factors to consider in infection?
History of allergy Renal function Hepatic function Whether immunocompromised Nil by mouth? Illness severity Ethnic origin Age Other medication? Pregnant, breastfeeding or taking contraceptive?
Aminoglycoside examples?
SANGT
Streptomycin Amikacin Neomycin Gentamicin Tobramycin
Why are the aminoglycosides given parenterally?
Not absorbed from the gut*
Risk of absorption in IBD and liver failure
How are Gentamicin doses calculated?
Loading and maintenance based on patient weight and renal function (using nomogram) with adjustments based on plasma-drug concentration
Duration of Gentamicin treatment?
Should not exceed 7 days where possible
When would Gentamicin be combined with a penicillin or metronidazole?
As “blind” therapy for serious undiagnosed infections.
What is Neomycin limited to?
Skin, mucous infections and reduce bacteria in colon before bowel surgery or in hepatic failure. Thus is because it is too toxic parentally and oral use may lead to malabsorption.
When would you avoid high dose once daily aminoglycosides?
CrCl <20mL / min Endocarditis due to Gram +ve HÁČEK endocarditis Total body burns > 20% Pregnancy*
*lack of evidence to recommend
Aminoglycosides cautions?
Dehydration (correct before)
Dose dependent s/e’s - muscular weakness
If used for more than 7 days
Elderly and children with RF (Nephrotoxicity more common)
Pregnancy (Vestibular / auditory nerve damage risk if used 2nd / 3rd trimester
Renal impairment (decrease dose and dosing frequency due to accumulation risk - ototoxicity and nephrotoxicity most common in renal failure)
Auditory / Vestibular issues (monitor during treatment)
When to measure Aninoglycoside concentrations?
After 3-4 doses in multiple daily dose regimen and dose change
1 hour after IM or IV “peak” and just before next dose “trough”
If aminoglycoside trough concentration is high what action should be taken? What if peak concentration is high?
Dose interval increased
Compared to - Dose decreased
Cautions and issues of Aminoglycosides?
May impair neuromuscular transmission so be wary of conditions with this (muscle weakness)
Keep parenteral treatment under 7 days where possible
Nephrotoxicity occurs most commonly in elderly and children with renal failure so renal function to be assessed before and during.
Ototoxicity occurs most commonly in renal failure, so serum drug concentration to be monitored.
Renal impairment may require dose interval adjustment and dose and interval adjusted if severe
Risk of auditory / vestibular damage if used during 2nd 3rd trimester (small with Genta and Tobra but avoid unless essential.
Serum drug conc must be monitored, 1 hour after administration and just before next dose
Antibiotic associated colitis
Ototoxicity / auditory damage
Electrolyte disturbances (low potassium, calcium and magnesium)
How would you deal with Tobramycin bronchospasm?
Use bronchodilator during test.
Describe the natural history of Hep c…
Day 0: Mild flu like symptoms (sometimes jaundice, dark urine, anorexia, smoking aversion and ab pain)
From 0.5 - 20 years 75-85% have it as a chronic infection
From 20-30years 20-30% develop cirrhosis of these 3-6% develop decompensated cirrhosis (20% mortality) and 1-4% / year hepatocellular carcinoma (58% mortality)
90% of hep c transmission is via injectable drug use, how else can it be transmitted?
Pre 1991 blood transfusion
Blood contamination
Babies born to Hep C mothers
HIV +ve men who have sex with men
How can you detect Hep C?
OraQuick
NAT (nucleus acid amplification testing)
General treatments for Hep C
Interferons
Direct acting antivirals
In the first year of the new revaluation four activities need to be undertaken and submitted, how does this change the following year?
Four CPD records undertaken and recorded (two planned, two unplanned) AND a peer discussion record and reflective account (a GPhC standard will be chosen by the pharmaceutical council for pharmacists to talk about practice over the past year, who the users are, and examples as to how the standards were met)
A mother comes in with her child presenting yellow brown blisters around the mouth and nose area, after ruling out cold sores and saying it’s likely to be impetigo you refer her to a doctor, she asks for information as to what the doctor will prescribe.
For minor localised impetigo topical Fusidic acid TDS / QDS for 7 - 10 days (mupirocin TDS UP TO 10 days if MRSA)
If widespread - oral Flucloxacillin for 7 days ( + Penicillin V if streptococci suspected) or Clindamycin/ Clarithromycin/ Erythromycin / Azithromycin
Why use broad spectrum with particular caution in immunocompromised individuals?
Increased risk of secondary infections and increased resistance and risk of antibiotic associated colitis (fever, bloody stools, abdominal pain)
What drugs are associated with antibiotic induced colitis?
Clindamycin Cephalosporins Fluoroquinolones Co-amoxiclav Ampicillin Amoxicillin
Why monitor hearing and renal function with patients on the aminoglycosides (Tobramycin, Stretomycin, Amikacin, Neomycin, Gentomycin) ?
Aminoglycosides are associated with ototoxicity (damages sensory cells in cochlea and vestibular organ leading to hearing loss, vertigo , balance loss and ataxia) and nephrotoxicity (tubule damage and electrolyte disturbances)
This means caution should be used in those with already impaired hearing, pregnant women (damage to foetus especially in 2nd / 3rd trimester) and Renault impaired / dehydrated (who you would avoid once daily dosing in)
Before treatment; hearing tests, dehydration correction
during plasma drug monitoring (peak and trough), RF, hearing
As well as patients who are renally impaired or on nephrotoxic drugs (NSAIDs, Loop diuretics, Cephalosporins, Tacrolimus) or with hearing issues or on ototoxic drugs (Vincas, Oxaplatin, Vancomycin), who else to look out for?
Aminoglycosides reduce acetylcholine release due to calcium uptake inhibition so should be used in caution in patients with muscular weakness disorders such as myasthenia gravis or taking drugs that cause neuromuscular blockage, such as Botulin toxins, Atracuronium, Neostigmine.
What antibacterial should be avoided in beta lactam hypersensitivity?
Cephalosporins
Carbapenems
Penicillin
Monobactam
