Methenamine

Question 1

T/F

Methenamine, itself, is not an ABX.

Answer 1

TRUE

requires acidic environment to be converted to formaldehyde, which kills by denaturing proteins

Question 2

How do you turn Methenamine into an ABX?

Answer 2

At adequate urine pH (

Question 3

How come Methenamine is used for UTI prophylaxis even though the stomach acid will activate it into formaldehyde?

Answer 3

Methenamine is enterically coated

Question 4

Why can’t Methenamine be given to a patient with a urinary catheter?

Answer 4

Frequent voiding of bladder (indwelling catheters or intermittent cath) will decrease effects by removing formaldehyde and by reducing the time of exposure of bladder bacteria to formaldehyde.

Urine concentration is low (pH is high) not acidic enough to activate Methenamine

Question 5

What is the Mechanism of Action for Methenamine?

Answer 5

No antibacterial effect alone. At adequate urine pH (

Question 6

How would you describe Methenamine bioavailability and excretion?

Answer 6

Very high bioavailability

renal excretion

Question 7

Why can’t you use Methenamine in patients with hepatic insufficiency?

Answer 7

Ammonia is a byproduct of Methenamine use; liver can’t clear extra ammonia

Question 8

Why can’t you use Methenamine in patients with renal insufficiency/failure?

Answer 8

acid forms could potentially lead to systemic acidosis

Question 9

Can Methenamine be used for treatment of acute UTI?

Answer 9

NO, PROPHYLAXIS ONLY

Question 10

What bugs are covered by Methenamine?

Answer 10

ALL BACTERIA AND FUNGI

urease+ like Proteus alkanize urine thereby disabling Methenamine activation