雙羥萘酸噻嘧啶 (Pyrantel Pamoate)
雙羥萘酸噻嘧啶是一種廣泛使用且極其安全的**嘧啶類驅蟲藥**，主要對多種動物腸道內的線蟲（如蛔蟲和鉤蟲）有效。 由於雙羥萘酸鹽在胃腸道的吸收極差，它能在目標寄生蟲所在的腸道管腔內達到高濃度。由於其極高的安全範圍和適口性佳的口服懸浮液劑型，它是獸醫小兒科（幼犬和幼貓常規驅蟲）的必備藥物。 > **臨床提示：** 雖然對蛔蟲和鉤蟲非常有效，但標準劑量的噻嘧啶對鞭蟲（*Trichuris* spp.）和大多數絛蟲無效。然而在馬匹中，雙倍劑量可用於控制迴盲瓣絛蟲（*Anoplocephala perfoliata*）。馬圓線蟲和犬鉤蟲（*Ancylostoma caninum*）的抗藥性是目前日益受關注的臨床問題。
作用機制: Pyrantel acts as a **depolarizing neuromuscular blocking agent** in susceptible parasites. * It binds selectively to **nicotinic acetylcholine receptors** on the somatic muscle cells of the nematode. * This binding causes continuous depolarization and an influx of calcium → **spastic paralysis** of the worm. * Paralyzed worms lose their ability to maintain attachment to the host's intestinal mucosa and are subsequently expelled alive in the feces via normal gastrointestinal peristalsis. * It also possesses mild **cholinesterase inhibitory** properties, further contributing to the accumulation of acetylcholine at the parasite's neuromuscular junction.
各物種劑量
- For susceptible parasites · Pyrantel tartrate: 25 mg/kg, PO · PO · Single dose
- For susceptible parasites · Pyrantel tartrate: 25 mg/kg, PO · PO · Single dose
- For susceptible parasites using combination product with praziquantel (Drontal) · Administer a minimum dose of 2.27 mg praziquantel and 9.2 mg pyrantel pamoate per pound of body weight according to the dosing tables on labeling. · PO · Single dose · May be given directly by mouth or in a small amount of food. Do not withhold food prior to or after treatment. If reinfection occurs, treatment may be repeated.
- Ascarids, Hookworms, Physaloptera · 5 mg/kg, PO; repeat in 2 weeks (one time only for Physaloptera) · PO · repeat in 2 weeks
- For susceptible parasites · 10 mg/kg PO, repeat in 3 weeks · PO · repeat in 3 weeks
- Kittens · 5-10 mg/kg PO; can be repeated every 2-3 weeks until at least 12 weeks of age. · PO · every 2-3 weeks · until at least 12 weeks of age · Can be treated as early as 2-3 weeks of age
- For susceptible parasites · Pyrantel tartrate: 25 mg/kg, PO · PO · Single dose
給藥途徑
禁忌症
- Severely debilitated animals
不良反應
- Emesis (rare, primarily in small animals)
藥物相互作用
- Diethylcarbamazine · Increased risk for adverse effects
- Levamisole · Because of similar mechanisms of action (and toxicity), do not use concurrently
- Morantel · Because of similar mechanisms of action (and toxicity), do not use concurrently
- Organophosphates · Increased risk for adverse effects
- Piperazine · Pyrantel and piperazine have antagonistic mechanisms of action; do not use together
監測
- Fecal egg count reduction testing (FECRT) for strongyle nematodes (especially in horses to monitor for resistance)
- Resolution of clinical signs of parasitism
- Routine fecal flotations 2-4 weeks post-treatment
過量
Pyrantel has a moderate to wide margin of safety. * Dosages up to approximately **7 times** the recommended dose generally result in no toxic reactions. * In horses, doses of **20X** yielded no adverse effects. * The LD50 in mice and rats for pyrantel tartrate is 170 mg/kg; >690 mg/kg for pyrantel pamoate in dogs. * **Chronic dosing** of pyrantel pamoate in dogs resulted in clinical signs when given at 50 mg/kg/day, but not at 20 mg/kg/day over 3 months. * **Clinical signs of toxicity** may include increased respiratory rates, profuse sweating (in species with sweat glands), ataxia, or other cholinergic effects.
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。