メテナミン馬尿酸塩

使用用途

• Urinary tract infection prophylaxis
• Urinary tract infection prophylaxis
• Urinary tract infection prophylaxis
• Urinary tract infection prophylaxis

投与方法

考えられる副作用

• Gastrointestinal irritation (nausea, vomiting, anorexia)
• Dysuria (secondary to formaldehyde irritation with long-term use)
• Systemic acidosis (potential)
• Lipoid pneumonitis (reported in humans using oral suspension)

注意事項と禁忌

• Hypersensitivity to methenamine or its salts
• Renal insufficiency
• Metabolic acidosis
• Severe hepatic impairment (due to ammonia production during hydrolysis)
• Severe dehydration
• > **Crucial Efficacy Requirement:** Urine pH MUST be kept below 6.5 (ideally ≤ 5.5) for the drug to be effective. * **Urea-Splitting Bacteria:** Infections with urea-splitting organisms (e.g., *Proteus*, some *Staphylococcus*, *Pseudomonas*) naturally alkalinize the urine, potentially rendering methenamine ineffective. * **Acidification Therapy:** Concurrent use of urinary acidifiers (e.g., methionine, ammonium chloride, ascorbic acid) or prescription acidifying diets is often required. * **Species Sensitivity:** Cats reportedly do not tolerate methenamine as well as dogs. * **Pregnancy:** FDA Category C. Crosses the placenta; use with caution during pregnancy. Enters milk, but no adverse effects reported in nursing offspring.

薬物相互作用

• Sulfamethiazole: Not recommended; an insoluble precipitate may form in the urine.
• Urine Alkalinizing Drugs (e.g., calcium/magnesium antacids, carbonic anhydrase inhibitors, citrates, sodium bicarbonate, thiazide diuretics): May reduce the efficacy of methenamine by preventing its conversion to formaldehyde in the urine.

よくある質問