マンニトール
マンニトールは、主に救急および集中治療の獣医療で使用される強力な**浸透圧利尿薬**です。細胞内から細胞外へ水分を引き寄せる糖アルコールです。 **主な適応症：** * **急性乏尿性腎不全**の管理（利尿の促進） * **頭蓋内圧（ICP）**および脳浮腫の低下（例：外傷性脳損傷） * 急性緑内障における**眼圧（IOP）**の低下 * 特定の毒素（アスピリン、バルビツール酸系、臭化物、エチレングリコールなど）の尿中排泄の促進 > **臨床のポイント：** マンニトールは急速な体液移動を引き起こすため非常に有効ですが、患者の体液量と水分状態の厳密なモニタリングが必要です。室温で結晶化する傾向があるため、インラインフィルターを使用して投与する必要があります。
作用機序: Mannitol is freely filtered at the glomerulus and poorly reabsorbed in the renal tubules. * **Osmotic Diuresis:** The presence of mannitol in the tubular fluid increases osmotic pressure → prevents water reabsorption → proportionately increases water excretion along with sodium, uric acid, and urea. * **Neuroprotection & ICP Reduction:** Increases intravascular osmolarity → draws water from brain parenchyma across an intact blood-brain barrier (BBB) into the intravascular space → decreases cerebral edema and CSF pressure. * **Renal Protection:** Dilates renal arterioles → decreases vascular resistance and blood viscosity → increases renal blood flow and glomerular filtration rate (GFR). It also minimizes renal tubular swelling and prevents the concentration of nephrotoxins in tubular fluid.
動物種別の用量
- Cerebral edema · 1-3 gram/kg IV · IV · Single dose · Usually given with steroids and/or DMSO.
- Oliguric renal failure · 1-2 gram/kg (5-10mL of 20% solution) IV · IV · Single dose · Give after rehydration; monitor urine flow and fluid balance.
- Cerebral edema · 1-3 gram/kg IV · IV · Single dose · Usually given with steroids and/or DMSO.
- Oliguric renal failure · 1-2 gram/kg (5-10mL of 20% solution) IV · IV · Single dose · Give after rehydration; monitor urine flow and fluid balance.
- Oliguric renal failure (not anuric) · 0.25-0.5 gram/kg IV over 5-10 minutes · IV · May repeat q4-6 hours or as CRI for first 12-24 hours · 12-24 hours · After correcting fluid, electrolyte, acid/base balance. CRI dose is 8-10% solution.
- Oliguric renal failure (rehydrated, not fluid overloaded) · 0.25-0.5 gram/kg IV slowly over 5-10 minutes; repeat dose at 30-40 minute intervals up to 1.5 gram/kg total · IV · q30-40min · Up to 1.5 g/kg total
- Oliguric renal failure (fluid replete) · 0.5 gram/kg IV over 20-30 minutes; if significant diuresis is accomplished within 30 minutes, may administer as a CRI of 60-120 mg/kg/hr IV or as intermittent boluses repeated every 4-6 hours · IV · CRI or q4-6h · Contraindicated in patients who are dehydrated, hypervolemic, or anuric.
- Acute glaucoma · 0.5-1 gram/kg IV given over 15-20 minutes · IV · Single dose · Withhold water for 3-4 hours. IOP reduction begins in 20-30 mins.
投与経路
禁忌
- Anuria secondary to renal disease
- Severe dehydration
- Severe pulmonary congestion or pulmonary edema
- Intracranial bleeding (unless during craniotomy - human label)
- Disrupted capillary membrane in the brain (can leak into interstitium and worsen edema)
- Severe pulmonary congestion
- Pulmonary oedema
- Intracranial haemorrhage (relative contraindication; labelled 'use with care' but commonly used in traumatic brain injury)
有害事象
- Fluid and electrolyte imbalances (especially hypernatremia)
- Volume overload (if oliguria persists)
- Nausea and vomiting
- Pulmonary edema
- Congestive heart failure (CHF)
- Tachycardia
- Dizziness and headache (CNS effects)
- Fluid and electrolyte imbalances
- Circulatory overload (at high doses)
- Acidosis (at high doses)
- Thrombophlebitis
- Extravasation injury (oedema and skin necrosis)
- Diarrhoea (if administered orally)
- Acute renal failure (rare)
薬物相互作用
- Lithium · Mannitol can increase the renal elimination of lithium
- Sotalol · Mannitol's effects on potassium and magnesium may increase the risk for QT prolongation
- Potassium-depleting diuretics · May exacerbate diuretic-induced hypokalaemia · moderate
- Beta-blockers · Concurrent use with potassium-depleting diuretics requires caution · moderate
- Ciclosporin · Nephrotoxicity has been described with concurrent use in humans · major
- Whole blood · Mannitol should never be added to whole blood for transfusion or given through the same IV set · major
- KCl or NaCl · Do not add to concentrated mannitol solutions (20% or 25%) as a precipitate may form · major
モニタリング
- Serum electrolytes (especially sodium)
- Serum osmolality
- BUN and serum creatinine
- Urine output
- Central venous pressure (CVP), if possible
- Lung auscultation (to monitor for pulmonary edema)
- Intracranial pressure (ICP) or neurological status
- Intraocular pressure (IOP)
- Hydration status and body weight
- Serum electrolytes (especially potassium and sodium)
- Renal function (BUN, creatinine)
- Acid-base balance
過量投与
Inadvertent overdosage can cause excessive excretion of sodium, potassium, and chloride. If urine output is inadequate, **water intoxication** or **pulmonary edema** may occur. **Treatment:** * Halt mannitol administration immediately. * Monitor and correct electrolyte and fluid imbalances. * Hemodialysis is effective in clearing mannitol from the bloodstream.
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。