替來他明 / 唑拉西泮
**替來他明/唑拉西泮**（常見商品名為 **Telazol®**）是獸醫學中廣泛使用的注射型麻醉劑與鎮靜劑組合。它以 1:1 的比例混合了兩種不同的藥理成分： * **替來他明 (Tiletamine)**：一種與氯胺酮 (Ketamine) 化學結構相關的解離性麻醉劑，可提供深度的鎮痛與失憶效果。 * **唑拉西泮 (Zolazepam)**：一種苯二氮平類輕度鎮靜劑，可提供肌肉鬆弛、抗焦慮作用，並抵消單獨使用解離性麻醉劑時通常會引起的肌肉僵硬和癲癇發作風險。 雖然美國 FDA 僅正式核准其用於犬貓的保定、小型手術及麻醉，但它在臨床上被廣泛標示外使用於多種動物，包括馬、反芻動物、豬、鳥類、爬蟲類及各種野生/特寵動物。 > **臨床要點：** 這兩種成分的作用時間因物種而異。在**犬隻**中，替來他明的作用時間長於唑拉西泮，導致恢復期鎮靜時間短於麻醉時間（可能造成恢復期較不平穩）。在**貓咪**中，唑拉西泮的作用時間長於替來他明，因此在恢復期會有較長時間的鎮靜狀態。
作用機制: The combination works synergistically through two distinct central nervous system pathways: * **Tiletamine** acts as a non-competitive **NMDA (N-methyl-D-aspartate) receptor antagonist**. By blocking the excitatory neurotransmitter glutamate at the NMDA receptor → it prevents calcium influx into neurons → inducing a state of **dissociative anesthesia** characterized by catalepsy, profound somatic analgesia, and amnesia, while maintaining cranial nerve reflexes (e.g., palpebral, laryngeal). * **Zolazepam** acts as a **GABA-A receptor agonist**. It binds to the benzodiazepine site on the GABA-A receptor complex → enhances the binding of the inhibitory neurotransmitter GABA → increases chloride ion influx → resulting in hyperpolarization of the neuron. This provides **muscle relaxation, anxiolysis, and anticonvulsant effects**, smoothing the induction and recovery phases of the dissociative anesthetic.
各物種劑量
- Induction agent · Xylazine at 0.05-0.1 mg/kg IV, IM, then Telazol at 2-4 mg/kg IV (IM) · IV/IM · Once · Caution: xylazine can cause severe hypoxemia and pulmonary edema in sheep.
- Induction agent · Xylazine at 0.05-0.1 mg/kg IV, IM, then Telazol at 2-4 mg/kg IV (IM) · IV/IM · Once
- Procedures such as dentistry, abscess treatment, foreign body removal · 9.7-11.9 mg/kg · IM · Once · Max total dose 72 mg/kg. Use Atropine 0.04 mg/kg concurrently.
- Procedures requiring mild to moderate analgesia (lacerations, castration) · 10.6-12.5 mg/kg · IM · Once · Max total dose 72 mg/kg. Use Atropine 0.04 mg/kg concurrently.
- Ovariohysterectomy and onychectomy · 14.3-15.8 mg/kg · IM · Once · Max total dose 72 mg/kg. Use Atropine 0.04 mg/kg concurrently.
- General anesthesia/restraint · 3-10 mg/kg IM or SC or 2-5 mg/kg IV · IM/SC/IV · Once · Based upon the combination of drugs.
- Sedative/analgesic · 22 mg/kg IM combined with glycopyrrolate (0.01 mg/kg IM) · IM · Once · Rapid onset, but slow and rough recovery (3-4 hours)
- Sedative/analgesic · 22 mg/kg · IM · Once · Telazol alone
給藥途徑
禁忌症
- Pancreatic disease
- Severe cardiac disease
- Severe pulmonary disease
- Rabbits (due to reports of renal toxicity/nephrosis)
- Large exotic cats, especially tigers (may cause seizures, permanent neurologic abnormalities, or death)
- Cesarean section (crosses placenta, causes fetal respiratory depression)
不良反應
- Respiratory depression and transient apnea
- Pain upon IM injection (especially in cats due to low pH)
- Athetoid movements (involuntary writhing/twitching)
- Tachycardia (especially in dogs)
- Emesis during emergence
- Excessive salivation and bronchial/tracheal secretions
- Vocalization and erratic/prolonged recovery
- Hypothermia
- Muscle rigidity or hypertonia
- Hypertension or hypotension
- Cyanosis, pulmonary edema, or cardiac arrest (rare/at high doses)
藥物相互作用
- Inhalational Anesthetics · Dosage may need to be reduced when used concomitantly with Telazol.
- Barbiturates · Dosage may need to be reduced when used concomitantly with Telazol.
- Chloramphenicol · In cats, anesthesia is prolonged on average by 30 minutes. No apparent effect on recovery times in dogs.
- Phenothiazines · Can cause increased respiratory and cardiac depression.
- Neuromuscular Blockers (e.g., succinylcholine) · May cause enhanced or prolonged respiratory depression (extrapolated from ketamine).
- Thyroid Hormones · May induce hypertension and tachycardia (extrapolated from ketamine).
- Azole Antifungals (ketoconazole, itraconazole) · May increase zolazepam (benzodiazepine) levels.
- Calcium Channel Blockers (diltiazem, verapamil) · May increase zolazepam levels.
- Cimetidine · May increase zolazepam levels.
- Macrolides (erythromycin, clarithromycin) · May increase zolazepam levels.
- Opiates · May increase hypnotic effects and risk of hypotension/respiratory depression.
- Phenobarbital · May decrease peak levels and AUC of zolazepam.
監測
- Level of anesthesia and analgesia
- Respiratory function (rate, depth, pulse oximetry)
- Cardiovascular status (heart rate, rhythm, blood pressure)
- Body temperature (monitor for hypothermia)
- Eye moisture and corneal integrity (especially in cats)
過量
The manufacturer claims a 2X margin of safety in dogs and a 4.5X margin of safety in cats. * **Clinical Signs:** Excessive respiratory depression, prolonged anesthesia, potential cardiovascular collapse. * **Treatment:** In massive overdoses, mechanically assisted ventilation should be performed if necessary. Treat other clinical signs symptomatically and supportively. * **Reversal/Stimulation:** A preliminary study in dogs suggests that **doxapram** at 5.5 mg/kg will enhance respirations and arousal after Telazol administration. > **Note:** High doses of tiletamine have caused acute tubular necrosis in New Zealand white rabbits.
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