Chapter 5 - Infection

Question 1

Patient factors to consider in infection?

Answer 1

History of allergy
Renal function
Hepatic function
Whether immunocompromised
Nil by mouth?
Illness severity
Ethnic origin
Age
Other medication?
Pregnant, breastfeeding or taking contraceptive?

Question 2

Aminoglycoside examples?

SANGT

Answer 2

Streptomycin
Amikacin
Neomycin
Gentamicin
Tobramycin

Question 3

Why are the aminoglycosides given parenterally?

Answer 3

Not absorbed from the gut*

Risk of absorption in IBD and liver failure

Question 4

How are Gentamicin doses calculated?

Answer 4

Loading and maintenance based on patient weight and renal function (using nomogram) with adjustments based on plasma-drug concentration

Question 5

Duration of Gentamicin treatment?

Answer 5

Should not exceed 7 days where possible

Question 6

When would Gentamicin be combined with a penicillin or metronidazole?

Answer 6

As “blind” therapy for serious undiagnosed infections.

Question 7

What is Neomycin limited to?

Answer 7

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.

Question 8

When would you avoid high dose once daily aminoglycosides?

Answer 8

CrCl <20mL / min
Endocarditis due to Gram +ve
HÁČEK endocarditis 
Total body burns > 20%
Pregnancy* 

*lack of evidence to recommend

Question 9

Aminoglycosides cautions?

Answer 9

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)

Question 10

When to measure Aninoglycoside concentrations?

Answer 10

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”

Question 11

If aminoglycoside trough concentration is high what action should be taken? What if peak concentration is high?

Answer 11

Dose interval increased

Compared to - Dose decreased

Question 12

Cautions and issues of Aminoglycosides?

Answer 12

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)

Question 13

How would you deal with Tobramycin bronchospasm?

Answer 13

Use bronchodilator during test.

Question 14

Describe the natural history of Hep c…

Answer 14

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)

Question 15

90% of hep c transmission is via injectable drug use, how else can it be transmitted?

Answer 15

Pre 1991 blood transfusion
Blood contamination
Babies born to Hep C mothers
HIV +ve men who have sex with men

Question 16

How can you detect Hep C?

Answer 16

OraQuick

NAT (nucleus acid amplification testing)

Question 17

General treatments for Hep C

Answer 17

Interferons

Direct acting antivirals

Question 18

In the first year of the new revaluation four activities need to be undertaken and submitted, how does this change the following year?

Answer 18

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)

Question 19

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.

Answer 19

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

Question 20

Why use broad spectrum with particular caution in immunocompromised individuals?

Answer 20

Increased risk of secondary infections and increased resistance and risk of antibiotic associated colitis (fever, bloody stools, abdominal pain)

Question 21

What drugs are associated with antibiotic induced colitis?

Answer 21

Clindamycin
Cephalosporins
Fluoroquinolones
Co-amoxiclav
Ampicillin
Amoxicillin

Question 22

Why monitor hearing and renal function with patients on the aminoglycosides (Tobramycin, Stretomycin, Amikacin, Neomycin, Gentomycin) ?

Answer 22

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

Question 23

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?

Answer 23

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.

Question 24

What antibacterial should be avoided in beta lactam hypersensitivity?

Answer 24

Cephalosporins
Carbapenems
Penicillin
Monobactam

Question 25

Why choose Teicoplanin over Vancomycin?

Answer 25

For patients with adherence issues the twice daily dosing is more convenient.

Less nephrotoxic (lower risk)

Both can still contribute to ototoxicity

Question 26

Why infuse Televancin and Vancomycin slowly?

Answer 26

If infusion is within 60 minutes risk of red man syndrome from Televancin

Rapid infusion of Vancomycin can lead to anaphylaxis and local site reactions.

Question 27

Why discontinue Clindamycin at first sign of diarrhoea even though it is a common side effect of other antibacterials (Carbapemens, Macrolides, Monobactams, Penicillins) ?

Answer 27

Antibiotic associated colitis is more commonly associated with Clindamycin than others.

Question 28

Why might you be cautious in patients receiving non depolarising blocking agents in surgery also give. Clindamycin?

Answer 28

Clindamycin can increase the effects of curoniums - Atracuronium, etc.

Question 29

What could you give a patient who is penicillin allergic?

Answer 29

A macrolide such as:
Azithromycin
Clarithromycin
Erythromycin

Question 30

Why use Azithromycin over the other macrolides?

Answer 30

Reduced incidence and milder GI effects such as abdominal pain, nausea and vomiting and diarrhoea.

Question 31

Why be wary of the following when prescribing macrolides:
Increased age
Female
Cardiac disease
Metabolic disturbances (hypokalaemia) ?

Answer 31

Macrolides alongside Citalopram, Lithium, Sildenafil increase risk of QT elongation and one of the risk factors hypokalaemia is worsened by steroids, beta agonists, diuretics and theophylline, Aminophylline.

The aforementioned factors of age, female sex and cardiac disease also contribute to QT elongation and can potentially cause torsade de points.

Question 32

Why might you not use a large dose in Erythromycin when given to a patient with renal impairment?

Answer 32

Risk of ototoxicity

Question 33

Why avoid alcohol with Metronidazole and Tinidazole?

Answer 33

Can inhibit conversion of acetyl aldehyde to acetic acid like Disulfiram (used to treat alcoholism) this large level
In the blood can cause flushing, tachycardia, hyperventilation, panic, distress, nausea and hypotension so should be avoided during the course and after finishing (48 hours Metronidazole and 72 with Tinidazole)

Question 34

Why use Metronidazole with caution in liver disease?

Answer 34

Site of action is the liver so dose should be reduced In severe liver disease and caution in hepatic encephalopathy

May cause liver sides.

Question 35

Why use caution when giving a long course of Metronidazole or Tinidazole with coumarins (Warfarin and Acenocoumarol) ?

Answer 35

These drugs increase the risk of peripheral neuropathy

Question 36

Why keep Metronidazole and Tinidazole under 10 days?

Answer 36

Over 10 days increases risk of leucopenia, peripheral neuropathy (ataxia, dizziness, convulsions) and transient epileptiform seizures so monitoring required of LF, leukocytes and signs of neuropathy.

Question 37

How can b lactamase resistance be dealt with?

Answer 37

Use of Flucloxacillin or Temocillin.

Addition of clavulanic acid which is a beta lactamase inhibitor, for example Co-amoxiclav

Question 38

Why do penicillins only get good CNS penetration if meninges inflammed?

Answer 38

Lipid insoluble do can’t pass through normally

Question 39

Why use high dose IV penicillins with caution in renal failure? Others drugs to watch out for too?

Answer 39

High dose of sodium can cause hypernatraemia leading to symptoms of weakness, thirst, nausea, vomiting , confusion.

Diuretics, Lithium and although not a drug - diarrhoea.

Question 40

Calistimethate via inhalation is used to treat pseudomonas aeruginisa infection in CF, why might you change to IV?

Answer 40

If a patient has severe haemoptysis nebuliser inhalation can cause bronchospasm, vomiting and cough leading to more damage (other side effects include sore mouth, taste disturbances)

IV will not cause this (although lower dose needed in renal impairment)

Question 41

Why avoid Quinolones in MRSA?

Answer 41

Most Staphylococci are resistant to this class of medicines that include Ciprofloxacin, Levofloxacin, Ofloxacin.

Question 42

Why would you recommend a patient on steroids to avoid Quinolones?

Answer 42

Increased risk of tendon damage that occurs in 48 hours of several months later (alongside being over 60 and previously having tendon damage from Quinolones)

Other cautions include convulsions risk being increased especially if on NSAIDs and if epileptic.

Question 43

What medication can reduce quinolone levels?

Answer 43

Ferrous and magnesium can decrease absorption and zinc can decrease exposure

Question 44

When prescribing Quinolones, why check Hx of MI, low heart beat, congenital QT elongation, electrolyte disturbances, HF, arrhythmias? And DHx for steroids, beta agonists, theophylline, diuretics, NSAIDs?

Answer 44

Acute MI, bradycardia, congenital QT elongation, hypokalaemia, HF with reduced LVF and symptomatic arrhythmias are risk factors for QT elongation

Hypokalaemia, one of the risk factors is caused by certain drugs including steroids (also increases risk of tendon damage), theophylline, beta agonists, and loop/ thiazides.

NSAIDs are associated with increased convulsion risk when taken with quinolones