Zahir SHAH, Ming Xing DING, Man Li HU

A review on the current use of Alpha2 agonists in small ruminants

Son yıllarda alfa2 antagonistleri çabuk etki, geridönüşebilirlilik ve analji gibi bazı özellikleri nedeniyle veteriner hekimlikte sedatif ve analjezik olarak en yaygın kullanılan ilaçlardır. Alfa2 antagonistleri merkezi sinir sisteminin çeşitli bölgelerinde yer alan ilişkili reseptörlere bağlanmak suretiyle değişik reaksiyonlara neden olur. Ruminantlar diğer türlerle karşılaştırıldığında spesifik alfa2 adenoreseptör subtipleri nedeniyle alfa2 antagonistlerine karşı özellikle sensitiflerdir. Ruminantlarda alfa2 antagonistleri genel olarak zapturapt, klinik tanı ve küçük cerrahiler amacıyla sedatif ve analjezik olarak kullanılır. Klinik deneyler analjezinin sedasyonun süresinin tümü boyunca mevcut olmadığını göstermektedir. Bu nedenle bu maddeler acılı veya büyük cerrahi müdahalelerde tek başlarına yeterli değillerdir. Alfa2 antagonistlerinin epidural uygulanması minimal sedatif veya kardiyovasküler etkiler ile birlikte muhtemel analjezi üretmektedir. Bu uygulama ayrıca ruminantlarda en güvenilir teknik olarak kabul edilmektedir. Alfa2 antagonistleri ayrıca preanastetik uygulama olarak da kullanılmaktadır ve bariz olarak anestetik ajanın az kullanımının sağlayıcı etkileri vardır. Bu ilaçlar fazla salivasyon, bradikardi, azalmış respirasyon oranı, azalmış rektal derece, hiperglisemi, uterus kontraksiyonları ve azalmış rumen ve barsak motilitesi gibi istenmeyen etkilere neden olabilir. Bu yan etkiler alfa2 antagonistlerinin dozuna ve uygulanma yoluna ve alfa2 adrenoseptör subtiplerine karşı seçiciliği ile ilişkilidir. Bu ilaçların hasta hayvanlarda kullanılmasından kaçınma konusunda dikkatli davranılmalıdır ve bu ilaçların alınmasını takiben hastanın durumu daima kontrol edilmelidir. Spesifik antagonistlerin mevcudiyeti ruminantlarda alfa2 antagonistlerin kullanılabilmesinde güvence oluşturur. Güvenlik amacıyla alfa2 antagonistlerinin uygun düşük dozu daima ruminantlarda tavsiye edilmektedir.

Alfa2 antagonistlerinin küçük ruminantlarda kullanımı üzerine bir derleme

In recent years, alpha2 agonists are the most widely used as sedative and analgesic drugs in veterinary medicine because of several useful properties like fast onset, reversibility and analgesia. Alpha2 agonists produce different actions by binding to their corresponding receptor subtypes located on various parts of the central nervous system. Ruminants are especially sensitive to alpha2 agonists due to the distribution of the specific alpha2 adrenoceptor subtypes, compared with other species. In ruminants, alpha2 agonists are generally used as sedatives and analgesics for restraint, clinical diagnosis, and minor surgeries. Clinical experiments indicated that analgesia does not exist throughout the period of sedation, so these agents alone are not sufficient for painful or major surgical procedure. Epidural administration of alpha2 agonists produced potent analgesia with minimal sedative or cardiovascular effects, and considered one of the most reliable techniques in ruminant. Alpha2 agonists also used as a preanesthetic medication and have been obviously anesthetic sparing effects. They causes some unwanted effects, such as excessive saliva, bradycardia, depressed respiratory rate, decreased rectal temperature, hyperglycemia, uterine contractions and decreased ruminal and intestinal motility. These side effects are influenced by the doses and administration routes of alpha2 agonists, and their selectivity to alpha2 adrenoceptor subtypes. Attentions should be taken to avoid the use of these agents in sick patients, while careful monitoring of the patient condition is always mandatory after receiving these agents. Fortunately, the availability of specific antagonists assures the uses of alpha2 agonists in ruminants. For the safety, an appropriate low dose of alpha2 agonists is always recommended in ruminants.

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