Infection

Question 1

Cephalosporins (3)

Answer 1

Cefaclor (2nd Gen), Cefotaxime (3rd Gen), Aztreonam

Like penicillins, these are also Beta-Lactam antibiotics (inhibit cell wall synthesis of bacteria). First generation Cephalosporins are active against predominantly Gram positive bacteria with successive generations having increased activity against Gram Negative (although often with reduced activity against Gram positive organisms)

Question 2

Tetracyclines (3)

Answer 2

Tetracycline, Doxycycline and Oxytetracycline

Tetracyclines inhibit protein synthesis (inhibit binding of aminoacyl-tRNA to the mRNA-ribosome complex). They are generally used for infections of the urinary, respiratory and intestinal tracts alongside the treatment of chlamydia (especially in patients allergic to beta-lactams and macrolides). Their use is now unpopular due to resistance in causative organisms.

Question 3

Aminoglycosides (2)

Answer 3

Gentamicin and Neomycin

Aminoglycosides inhibit protein synthesis (usually in Gram negative bacteria but also some anaerobic bacilli but generally not against Gram positive). Therefore they are used to treat Pseudomonas, Acinetobacter and Enterobacter and some Mycobacteria (including Mycobateria TB).

Aminoglycosides are contraindicated in Myaesthenia Gravis as they can exacerbate weakness.

Question 4

Macrolides (2)

Answer 4

Erythromycin and Clarithromycin

Macrolides are protein synthesis inhibitors (prevention of Replication so bacteriostatic). They are used to treat Gram Positive infections (e.g Strep pneumoniae) and a limited number of Gram Negative infections (incl. H. Influenzae and Bordetella Pertussis (causative agent of whooping cough)). They have a slightly wider antimicrobial spectrum an penicillins so are commonly indicated in patients with penicillin allergies. Unlike penicillins, they are effective against legionella pneumophila, mycoplasma, Mycobacteria and chlamydia.

Question 5

Other antibacterials - Vancomycin

Answer 5

Vancomycin is recommended IV as first line treatment for skin infections, bloodstream infections, endocarditis, bone and joint infections and meningitis caused by MRSA. It is indicated for treatment in serious, life-threatening infections with Gram positive bacteria that is unresponsive to other antibiotics. It. is recommended as oral treatment for C. Diff colitis.

ADRs include:
Common: local pain at site of IV and thrombophlebitis
Infrequent: Nephrotoxic (increased risk if taken with Aminoglycosides)
Rare: anaphylaxis, thrombocytopenia, tinnitus, dizziness, ototoxicity

Question 6

Anti-TB Drugs (4)

Answer 6

Rifampicin, isoniazid, pyrazinamide, ethambutol (RIPE)

Initial treatment is with all four drugs for two months, then this is dropped down to two drugs for a further four months. (Multiple drugs are used to try and combat resistance). NB. As this is a long regime of drugs with many different pills, this can lead to problems with compliance. Therefore people can undergo Directly Observed Therapy which improves cure rates and reduces drug resistance and relapses.

Drug-Specific ADRs:
Rifampicin: Hepatitis, shock, thrombocytopenic purpura, flu-like symptoms, acute renal failure
Isoniazid: Peripheral Neuropathy, Hepatitis, Rash
Pyrazinamide: Hepatitis, Rash, Arthralgia
Ethambutol: Optic Neuritis

Question 7

Antiviral Drugs (4)

Answer 7

Amantidine, Rimantidine, Zanamivir, Oseltamivir

Amantidine and Rimantidine are M2 ion channel blockers so prevent viral uncoating (as H+ ions cannot gain entry into the virus through M2 ion channels to cause a drop in pH that would cause the viral coat to break down and allow spread of the virus). Their use is limited to Influenza A. ADRs include dizziness, GI disturbance, hypotension, confusion and insomnia (problematic in elderly where some may already be present - exacerbations). Rimantidine is preferably used as it has fewer side effects.

Zanamivir and Oseltamivir (Tamiflu - doesn’t work so assuming we don’t need to know Oseltamivir) are Neuraminidase inhibitors. Neuraminidase is required for the virus to escape the host cell by breaking the bonds between the cell membrane and the virus. Therefore the virus cannot spread from the host cell. They can be used to treat both Influenza A and B. ADRs include GI disturbance, headaches and epistaxis.

Question 8

Penicillins (4) available

Answer 8

Penicillin, Amoxicillin, Flucloxacillin, Co-Amoxiclav

Penicillins are Beta-Lactam antibiotics. These inhibit the formation of peptidoglycan cross-links in the bacterial cell wall. This causes an imbalance between cell wall production and degradation (as bacteria constantly remodel their cell walls) and the bacteria rapidly die.

Question 9

Antifungals (3)

Answer 9

Nystatin, Clotrimazole, Amphotericin

(I’m also assuming topical Azoles such as fluconazole but this isn’t on the required drug name sheet).

Question 10

Antiprotozoals (2)

Answer 10

Antimalarials (e.g. Chloroquine), Metronidazole