塞拉菌素
塞拉菌素是一種廣效、半合成的阿維菌素類局部抗寄生蟲藥，廣泛應用於獸醫學。 **主要臨床特點：** * **廣效性：** 對多種體內外寄生蟲有效，包括心絲蟲幼蟲、跳蚤、耳疥蟲、疥癬蟲及某些壁蝨。 * **貓腸道寄生蟲：** 在貓身上，對鉤蟲和蛔蟲也有效。 * **安全性高：** 即使在對阿維菌素敏感的犬種（如帶有MDR1基因突變的牧羊犬）中，按照標籤建議劑量局部使用也非常安全。 * **全身吸收：** 與許多僅停留在皮膚脂質層的局部除蚤/壁蝨產品不同，塞拉菌素會被全身吸收，這是其對抗心絲蟲和體內寄生蟲發揮效用的必要條件。
作用機制: Selamectin acts by binding to **glutamate-gated chloride channels** in the nervous system of invertebrates. Binding → increased permeability of the cell membrane to chloride ions → hyperpolarization of the nerve or muscle cell → **flaccid paralysis and death** of the parasite. *Clinical Pearl:* Mammals generally lack glutamate-gated chloride channels, and macrocyclic lactones do not readily cross the intact mammalian blood-brain barrier (mediated by P-glycoprotein), conferring a high margin of safety.
各物種劑量
- Heartworm prevention, flea control, ear mites, hookworms, roundworms · 6 mg/kg · topical · monthly (ear mites, hookworms, roundworms = once, repeat in one month if necessary)
- Notoedric (face/head) mange (Notoedres cati) · 6 mg/kg · topical · once
- Biting lice · 6 mg/kg · topical · once
- Flea treatment/prevention, heartworm prevention, ear mites, biting lice, roundworms, hookworms · 6 mg/kg · topical · monthly · Ongoing for prevention · Apply to the skin at the base of the neck in front of the shoulder blades.
- Heartworm prevention · 18 mg/kg · topical · every 30 days
- Flea treatment/prevention, heartworm prevention (Off-label / specific regional labels) · 15 - 18 mg/kg · topical · monthly · Ongoing for prevention · Use the kitten/small cat pipette.
- Ear mites (P. cunuculi) in rabbits · 6-18 mg/kg · topical · once
- Mites and fleas (Off-label) · 6 - 18 mg/kg · topical · monthly · As needed · Off-label use. Dose varies by species (e.g., rabbits, guinea pigs).
- Prophylaxis and treatment of dirofilariasis, flea control, ticks, ear mites, sarcoptes · 6 mg/kg · topical · monthly (ticks may repeat 2 weeks after first dose if heavy; ear mites/sarcoptes once, repeat in one month if necessary)
- Nasal mites (Pneumonyssoides caninum) · 6-24 mg/kg · topical · three times at 2-week intervals · 6 weeks
- Cheyletiellosis · 6-12 mg/kg · topical · every other week · total of four treatments
- Biting lice · 6 mg/kg · topical · once
- Flea treatment/prevention, heartworm prevention, ear mites, sarcoptic mange, biting lice · 6 mg/kg · topical · monthly · Ongoing for prevention; 1-2 doses for mite/lice treatment · Apply to the skin at the base of the neck in front of the shoulder blades.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Application to broken skin
- Application to wet hair coats
- Use in severely debilitated or underweight animals (relative)
- Puppies and kittens under 6 weeks of age
- Sick, debilitated, or severely underweight animals
- Known hypersensitivity to the active substance or excipients
不良反應
- Transient localized alopecia at application site (rare)
- Mild, transient gastrointestinal signs (vomiting, diarrhea) if ingested
- Transient local alopecia at the application site
- Application site irritation or pruritus
- Rarely: vomiting, diarrhea, lethargy, or anorexia
- Rarely: neurological signs (tremors, ataxia) in highly sensitive individuals
藥物相互作用
- Other macrocyclic lactones (e.g., ivermectin, milbemycin) · Potential for additive toxicity, though selamectin has a high margin of safety. · minor
- P-glycoprotein inhibitors (e.g., ketoconazole, cyclosporine) · May theoretically increase systemic absorption and CNS penetration, increasing the risk of toxicity. · moderate
監測
- Clinical efficacy
- Owner compliance with treatment regimen
- Efficacy of parasite control
- Application site for signs of irritation or alopecia
過量
Generally very safe. Overdoses up to 10 times the recommended dose typically do not produce clinical signs in dogs or cats. If massive accidental ingestion occurs, monitor for neurologic signs (ataxia, tremors, mydriasis) and provide supportive care.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。