Polymyxin B Sulphate, Trimethoprim

Indications

Polymyxin B Sulphate, Trimethoprim is used for: POLYMYXIN B SULFATE
For treatment of infections of the urinary tract, meninges, and blood stream, caused by susceptible strains of pseudomonas aeruginosa
TRIMETHOPRIM
For the treatment of urinary tract infections, uncomplicated pyelonephritis (with sulfamethoxazole) and mild acute prostatitis. May be used as pericoital (with sulfamethoxazole) or continuous prophylaxis in females with recurrent cystitis. May be used as an alternative to treat asymptomatic bacteriuria during pregnancy (only before the last 6 weeks of pregnancy). Other uses include: alternative agent in respiratory tract infections (otitis, sinusitus, bronchitis and pneumonia), treatment of pneumocystis jirovecii pneumonia (acute or prophylaxis), nocardia infections, and traveller's diarrhea

Adult Dose

Child Dose

Renal Dose

Administration

Contra Indications

Precautions

Pregnancy-Lactation

Interactions

Adverse Effects

Side effects of Polymyxin B Sulphate, Trimethoprim :

Mechanism of Action

POLYMYXIN B SULFATE
Polymyxin b sulfate has a bactericidal action against almost all gram-negative bacilli except the proteus group. Polymyxin b sulfate interacts with the lipopolysaccharide of the cytoplasmic outer membrane of gram-negative bacteria, altering membrane permeability and causing cell death. It does not need to enter the cell
TRIMETHOPRIM
Trimethoprim binds to dihydrofolate reductase and inhibits the reduction of dihydrofolic acid (dhf) to tetrahydrofolic acid (thf). Thf is an essential precursor in the thymidine synthesis pathway and interference with this pathway inhibits bacterial dna synthesis. Trimethoprim's affinity for bacterial dihydrofolate reductase is several thousand times greater than its affinity for human dihydrofolate reductase. Sulfamethoxazole inhibits dihydrofolate synthetase (aka dihydropteroate synthetase), an enzyme involved further upstream in the same pathway. Trimethoprim and sulfamethoxazole are commonly used in combination due to their synergistic effects. This drug combination also reduces the development of resistance that is seen when either drug is used alone