urinary tract infection and its management, nitrofurantoin and methenamine

1. URINARY TRACT
INFECTION
SHAHJAHAN
Neelkanth college of
Pharmacy,Jaunpur

2. URINARY TRACT INFECTION
A urinary tract infection (UTI) is an infection that
affects part of the urinary tract.
When it affects the lower urinary tract it is known as
a bladder infection (cystitis) and when it affects the
upper urinary tract it is known as a kidney infection
(pyelonephritis).
The most common cause of infection is Escherichia
coli, though other bacteria or fungi may sometimes
be the cause.[

3. SYMPTOM
Symptoms from a lower urinary tract infection
include-
 pain with urination,
 frequent urination,
 feeling the need to urinate despite having an
empty bladder.
Symptoms of a kidney infection include
Fever
flank pain usually in addition to the symptoms of
a lower UTI
Rarely the urine may appear bloody

4. TREATMENT
Non Specific Treatment
More water intake
Maintaining Acidity of urine
Drugs commonly recommended for UTIs include:
Nitrofurantoin
Methenamine
Trimethoprim/sulfamethoxazole
Fosfomycin
Cephalexin
Ceftriaxon

5. NITROFURANTOIN
Nitrofurantoin is a synthetic nitrofuran that is used for the prevention and
treatment of urinary tract infection.
It is active against certain Gram positive and Gram negative bacteria.
Nitrofurantoin is bactericidal in urine at therapeutic dose.

6. MECHANISM OF ACTION
Nitrofurantoin is reduced by bacterial flavoproteins and highly reactive
intermediates are formed.
This active form inactivates or alter bacterial ribosomal proteins and other
macromolecules
As a result of such inactivations- the vital biochemical processes of protein
synthesis , RNA synthesis, DNA synthesis, cell wall synthesis are inhibited.

7. NITROFURANTOIN
Reduction Bacterial Flavoprotein
Highly reactive intermediates
Inactivation of ribosomal proteins
Inhibition of DNA, RNA, Protein & Cell wall synthesis
Fig: Mechanism of action of Nitrofurantoin

8. PHARMACOKINETICS
Nitrofurantoin is absorbed rapidly and completely from the GIT.
The plasma half life is 0.3 to 1 hr.
About 40% is excreted unchanged into the urine.
The oral dosage of nitrofurantoin for adult is 50 to 100mg four times a day with
meals and at bedtime.

9. ADVERSE EFFECTS
The most common side effects with nitrofurantoin are nausea, headache,
and flatulence. Less common adverse events (occurring in less than 1% of
those taking the drug) include-
Gastrointestinal: diarrhea, dyspepsia, abdominal pain,
constipation, emesis
Neurologic: dizziness, drowsiness
Respiratory: acute pulmonary hypersensitivity reaction
Allergic: pruritus, urticaria
Dermatologic: hair loss
Miscellaneous: fever, chills, malaise

10. METHENAMINE
Methenamine is a heterocyclic organic compound with antibiotic
activity.
It is a prodrug that owes its activity to its capacity to generate
formaldehyde.
Methenamine is typically used long-term to treat chronic urinary
tract infections and to prevent the recurrence of infections.
Nearly all bacteria are sensitive to free formaldehyde at
concentration of about 20µg/ml.

11. MECHANISM OF ACTION
In a more acidic environment (pH<6), methenamine is hydrolyzed
to formaldehyde.
 Formaldehyde is considered to be highly bactericidal.
Formaldehyde has nonspecific antibacterial activity and works by
denaturing proteins and nucleic acid of bacteria.

12. METHENAMINE
Hydrolysis acidic pH(<6)
Formaldehyde
Protein Denature Nucleic Acid Denature
Fig: Mechanism of Action of Methenamine

13. PHARMACOKINETIC
After oral administration, rapid absorption of methenamine occurs.
In acidic urine (pH<6), methenamine is hydrolyzed to formaldehyde
which acts as an antiseptic.
Methenamine is primarily eliminated via the kidneys.

14. ADVERSE EFFECTS
GI disturbances
Nausea
Vomiting
Diarrhea
Abdominal cramps
Anorexia
Pruritus

Dysuria.