Drugs Used for GI Infestation

Question 1

Fluid replacement therapy

Answer 1

● Isotonic fluid loss → ORS → replacement of water and electrolyte
● Replace established deficit and ongoing losses
● Start antimicrobial therapy in non-specific gastroenteritis OR if there is systemic involvement OR if patient is immunocompromised OR if patient has significant comorbidity (HTN, HF, etc)

Question 2

Antibiotics (used for Shigella dysenteriae, invasive type salmonella, cholera epidemics)

Answer 2

β lactam antibiotic ( Cephalosporins)
Quinolones ( Ciproflaxacin )
Fluoroquinolone
Mebendazole
Albendazole
Metronidazole

(Mebendazole, Albendazole, Metronidazole ) are given for anti helminths as well

Question 3

What are the 5 generations of Cephalosporins

Answer 3

1st - cephalexin
2nd - cefuroxime
3rd - ceftriaxone
4th - cefepime
5th - ceftaroline

Question 4

1st - cephalexin Indication and therapeutic use

Answer 4

Gram +ve cocci
UTI, RTI, sinus, skin infection

Question 5

2nd - cefuroxime Indication and therapeutic use

Answer 5

Gram +ve/-ve cocci
RTI, surgical prophylaxis

Question 6

3rd - ceftriaxone Indication and therapeutic use

Answer 6

2nd gen + can cross BBB
Meningitis, pseudomonas

Question 7

4th - cefepime Indication and therapeutic use

Answer 7

Pseudomonas, MRSA, Staph aureus, Staph pneumoniae
Empirical therapy in serious infection (septic shock)

Question 8

5th - ceftaroline Indication and therapeutic use

Answer 8

Last line of defence
Community-Acquired Pneumonia

Question 9

MOA of β lactam antibiotic ( Cephalosporins)

Answer 9

Cell wall synthesis
inhibitor
Covalently bind to the active site of PBPs → inhibits transpeptidase reaction → alters peptidoglycan synthesis → cell dies
Bactericidal

Question 10

MOA of Ciprofloxacin ( Quinolones)

Answer 10

Blocks DNA gyrase (topoisomerase II) → prevent relaxation of supercoiled DNA (relaxed DNA is needed for transcription)

Inhibit topoisomerase IV → replicated chromosomes cannot separate during cell division

Bactericidal

Question 10

AE of β lactam antibiotic ( Cephalosporins)

Answer 10

Allergy (fever, skin rash, anaphylaxis)
Local irritation (IM injection), renal and hepatotoxicity, thrombophlebitis
Disulfiram-like reactions
Antibiotic associated diarrhoea

DDI
Drug alters effectiveness of OC pill
*Must warn patients taking OC pill

Patients with history of penicillin should not be given any β lactam antibiotics

A drug that causes an adverse reaction to alcohol → nausea, vomiting, flushing, throbbing headache, chest pain, general hangover symptoms among others

Question 11

Therapeutic Use of Ciprofloxacin ( Quinolones)

Answer 11

RTI (CAP, Legionella pneumonia), STD (Gonorrhoea), GIT infection (food poisoning, biliary tract infection), UTI, bone and soft tissue infection

Earlier agents are only effective against Gram -ve
Newer agents can target Gram -/+ve

Question 12

AE of Ciprofloxacin ( Quinolones)

Answer 12

Ruptures achilles tendon (x use in patients <18 y/o), arthropathy

Nausea, vomiting, diarrhoea

Antibiotic associated diarrhoea

Avoid in G6PD deficiency
*May cause convulsions, hallucinations

Question 13

DDI of Fluoroquinolone

Answer 13

● with divalent/trivalent cations (Mg2+, Ca2+, Al3+) → impair absorption of quinolones THUS CANNOT TAKE AT THE SAME TIME

● with warfarin → enhances effect of warfarin → anticoagulant → prevents blood clot

● with theophylline → increases conc. SO MUST REDUCE DOSE OF THEOPHYLLINE WHEN TAKING TOGETHER