UTI-Specific Antibiotics

Question 1

What are the 3 main-line Abx used for UTI infections?

Answer 1

1. Nitrofurantoin (PO)
2. Fosfomycin (PO)
3. Methenamine (PO)

Question 2

What is Nitrofurantoin commonly used for, how long is it administered, and what can it NOT be used to treat?

Answer 2

Use: LOWER tract UTIs (cystitis), typically administered for 7 days

CANNOT use for pyelonephritis due to poor kidney tissue penetration

Question 3

What two lung side-effects can Nitrofurantoin cause?

Answer 3

1. Hypersensitivity Pneumonitis (7-10 days post Tx)
2. Pulmonary Fibrosis (months after Tx)

Question 4

What is the MOA of Fosfomycin?

Answer 4

inhibits cell wall synthesis by interfering with peptidoglycan synthesis

Question 5

How is Fosfomycin typically administered and what can it NOT be given for?

Answer 5

Typically administered in one-time mega-dose of 3 grams

• like Nitrofurantoin, cannot be used to treat PYELONEPHRITIS

Question 6

What is the MOA of Methenamine?

Answer 6

converted to formaldehyde in the bladder, leading to bacteriostatic effect

• requires acidic environment to work (pH < 5.5) so ineffective vs Proteus