水酸化マグネシウム
水酸化マグネシウムは獣医学において経口制酸剤および下剤として使用されます。小動物では胃酸過多や潰瘍の治療に使用されてきましたが、現在ではより効果的な薬剤に取って代わられています。反芻動物では、第一胃過負荷症候群（第一胃アシドーシス）の治療において、粉末製剤が非常に効果的です。
作用機序: Acts locally in the gastrointestinal tract: * **Antacid**: Neutralizes gastric hydrochloric acid (HCl) → raises gastric pH. Raising pH >4 minimizes pepsin proteolytic activity, reducing gastric mucosal damage. * **Laxative**: Poorly absorbed magnesium ions create an osmotic gradient → draws water into the intestinal lumen → distends the bowel → stimulates peristalsis. * **Rumen Alkalinizer**: Directly neutralizes excess lactic acid produced during grain overload → increases rumen pH and alters rumen microflora activity.
動物種別の用量
- Rumen overload syndrome · As above for cattle, but use ⅛th-¼th the amount · PO · q6-12h
- Rumen overload syndrome · As above for cattle, but use ⅛th-¼th the amount · PO · q6-12h
- Antacid · 5-15 mL PO once to twice daily · PO · q12-24h · Using Milk of Magnesia
- Rumen overload syndrome (Adults) · Up to 1 gram/kg (MgOH) mixed in 2-3 gallons of warm water and given PO per tube. May repeat (use smaller doses) at 612 hour intervals. If the rumen has been evacuated, do not exceed 225 grams initially. · PO · q6-12h · Dehydration and systemic acidosis must be concomitantly corrected.
- Rumen overload syndrome (Calves) · As above but use ⅛th-¼th the amount · PO · q6-12h
- Adjunctive gastroduodenal ulcer therapy in foals · 15 mL 4 times a day · PO · q6h · Using Aluminum/magnesium hydroxide suspension
- Adjunctive treatment of hypomagnesemia with GI disease and severe hypocalcemia · 5-15 mL/per dog per 24 hours · PO · q24h · Using Milk of Magnesia
- Adjunctive therapy for gastric ulcers · 2-10 mL PO q2-4h · PO · q2-4h · Using Aluminum hydroxide suspension or aluminum hydroxide/magnesium hydroxide suspension
- Antacid · 5-30 mL PO once to twice daily · PO · q12-24h · Using Milk of Magnesia
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Renal disease (due to risk of hypermagnesemia)
- Gastric outlet obstruction (for aluminum-containing products)
- Use cautiously in patients on sodium- or potassium-restricted diets (some products contain significant amounts)
有害事象
- Diarrhea or frequent loose stools
- Hypermagnesemia (especially in patients with severe renal insufficiency)
- Constipation (if using combination products with aluminum)
- Hypophosphatemia (with chronic use of aluminum-containing products)
薬物相互作用
- Quinidine · Increased absorption or pharmacologic effect may occur
- Sodium Polystyrene Sulfonate · May decrease the potassium-lowering effectiveness; may cause metabolic alkalosis in renal failure patients
- Sustained-release medications · May alter absorption by changing GI transit times when used at laxative dosages
- Sympathomimetic agents · Increased absorption or pharmacologic effect may occur
- Fluoroquinolones · Decreased absorption (chelation); separate doses by at least 2 hours
- Tetracyclines · Decreased absorption (chelation); separate doses by at least 2 hours
- Azole Antifungals (Ketoconazole, Itraconazole) · Decreased absorption due to increased gastric pH; separate doses by at least 2 hours
- Digoxin · Decreased absorption; separate doses by at least 2 hours
- Iron Salts · Decreased absorption; separate doses by at least 2 hours
- H-2 Antagonists · Decreased absorption; separate doses by at least 2 hours
- Thyroid Hormones · Decreased absorption; separate doses by at least 2 hours
- Corticosteroids · Decreased absorption; separate doses by at least 2 hours
モニタリング
- Electrolyte imbalances (Magnesium, Phosphorus, Calcium) with chronic or high-dose therapy
- Renal function
- Fecal consistency
過量投与
Chronic or acute overdose can lead to significant GI upset (severe diarrhea) and electrolyte imbalances (hypermagnesemia, especially in renal failure). Treat symptomatically with fluid therapy and correct electrolyte derangements.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。