安普羅鎓
安普羅鎓是一種廣泛使用的**抗球蟲藥**，結構上類似於硫胺素（維生素B1）。雖然FDA主要核准用於家禽和牛隻以治療和預防艾美球蟲（*Eimeria*）感染，但它也常被標示外使用於伴侶動物、小型哺乳動物和特寵，以治療球蟲症（例如犬貓的等孢球蟲 *Cystoisospora* spp.）。 **臨床要點：** * 由於它作為硫胺素的競爭性抑制劑，短期使用的安全範圍通常很廣，但長期使用可能會引發硫胺素缺乏症（反芻動物的腦灰質軟化症或小動物的神經症狀）。 * 療程通常不應超過12-14天。 * 液體製劑非常苦；當透過飲水給藥時，必須密切監測病患以確保攝取足夠的水分。
作用機制: Amprolium is a **thiamine (Vitamin B1) analog**. It competitively inhibits the active transport and utilization of thiamine by the parasite. * **Mechanism:** Amprolium → blocks thiamine uptake → disrupts carbohydrate metabolism in the parasite (specifically inhibiting **thiamine pyrophosphate (TPP)**-dependent enzymes) → parasite death. * It primarily targets the **first-generation schizont** in the cells of the intestinal wall, preventing differentiation into merozoites. It may also suppress the sexual stages and sporulation of oocysts. * Because the host's thiamine transport mechanisms have a lower affinity for amprolium than the parasite's, toxicity to the host is minimized during short-term therapy.
各物種劑量
- Coccidiosis (Lambs) · 55 mg/kg daily · PO · q24h · 19 days
- Eimeria macusaniensis (Camelids - New World) · 10 mg/kg · PO · q24h · 5 days · Dosed for camelids
- Eimeria macusaniensis (Camelids - New World) · 10 mg/kg as a 1.5% solution · PO · q24h · 10-15 days · Give thiamine at 10 mg/kg SC once daily every 5 days during treatment. Dosed for camelids.
- Coccidiosis (Small Pups < 10 kg adult weight) · 100 mg (total dose) · PO · q24h · 7-12 days · Using the 20% powder in a gelatin capsule
- Coccidiosis (Large Pups > 10 kg adult weight) · 200 mg (total dose) · PO · q24h · 7-12 days · Using the 20% powder in a gelatin capsule
- Coccidiosis (Pups or bitches, in food) · 250-300 mg total dose · PO · q24h · 7-12 days · Using the 20% powder on food
- Coccidiosis (Pups or bitches, in water) · 30 mL of the 9.6% solution in one gallon of water · PO · ad libitum · 7-10 days · No other water provided
- Prophylaxis · 0.075% solution as drinking water · PO · ad libitum
- Coccidiosis (Combination therapy) · 150 mg/kg of amprolium and 25 mg/kg of sulfadimethoxine · PO · q24h · 14 days
- Control of coccidiosis · 1.5 tablespoonsful (22.5 mL) of the 9.6% solution per one gallon of water · PO · ad libitum · Not to exceed 10 days · Sole drinking water source. Monitor water consumption; rarely some dogs may not drink due to bitter taste.
給藥途徑
禁忌症
- Prolonged use (>12-14 days) especially in puppies
- Concurrent high-dose thiamine supplementation (reduces efficacy)
不良反應
- Neurologic disturbances (rare, dose-related)
- Depression
- Anorexia
- Diarrhea
- Thiamine deficiency (polioencephalomalacia) with prolonged high doses
藥物相互作用
- Thiamine · Exogenously administered thiamine in high doses may reverse or reduce the anticoccidial efficacy of amprolium.
- Thiamine (Vitamin B1) · Exogenously administered thiamine may reduce the efficacy of amprolium. · major
監測
- Clinical efficacy (resolution of diarrhea, negative fecal floats)
- Hydration status (especially if administered in drinking water)
- Neurologic signs (ataxia, depression) indicating potential thiamine deficiency
過量
Amprolium has induced **polioencephalomalacia (PEM)** in sheep when administered at 880 mg/kg PO for 4-6 weeks and at 1 gram/kg for 3-5 weeks. Erythrocyte production also ceased in lambs receiving these high dosages. In dogs, overdoses of amprolium will produce neurologic clinical signs. **Treatment:** * Discontinue amprolium therapy immediately. * Administer parenteral thiamine (1-10 mg/day IM or IV).
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