라니티딘

H2 수용체 길항제 / 위장관 운동 촉진제

**라니티딘(Ranitidine)**은 수의학에서 널리 사용되는 경쟁적 히스타민 H2 수용체 길항제이자 위장관 운동 촉진제입니다. **주요 임상 특징:** * **위산 억제:** 위궤양, 제4위 궤양, 십이지장 궤양, 요독성 위염 및 스트레스나 약물로 인한 미란성 위염의 치료 및 예방에 사용됩니다. * **위장관 운동 촉진:** H2 차단제 중 독특하게도 라니티딘은 위장관 운동을 자극하여 위 배출 지연을 개선하고 고양이의 결장 활동(예: 거대결장증)을 촉진하는 데 유용합니다. * **전신성 비만세포증:** 비만세포종(다량의 히스타민을 방출함)과 관련된 위산 과다 분비 상태를 관리하는 데 도움을 줍니다. > **임상 요점:** 라니티딘은 몰 농도 기준으로 시메티딘보다 3~13배 더 강력합니다. 또한 간의 사이토크롬 P450 효소를 크게 억제하지 않으므로 약물 상호작용이 현저히 적어 다중 약물을 복용 중인 환자에게 더 안전한 선택입니다.

작용 기전: Ranitidine exerts its effects via two distinct mechanisms: 1. **Gastric Acid Suppression:** It competitively inhibits **histamine** at the **H2 receptors** located on the basolateral membrane of gastric parietal cells. * Histamine blockade → decreased intracellular cAMP → reduced activation of the **H+/K+ ATPase (proton pump)** → significant reduction in both basal and stimulated gastric acid and pepsin secretion. 2. **Prokinetic Effect:** It reversibly inhibits **acetylcholinesterase (AChE)** in the gastrointestinal tract. * AChE inhibition → decreased breakdown of acetylcholine → increased **acetylcholine (ACh)** at muscarinic receptors → stimulation of GI smooth muscle motility and increased lower esophageal sphincter pressure.

동물 종별 용량

Cats

For ulcer disease/esophagitis · 2.5 mg/kg IV q12h or 3.5 mg/kg PO q12h · IV, PO · q12h
For ulcer disease/esophagitis · 1-2 mg/kg · PO, IV, SC · q12h
For ulcer disease/esophagitis · 2 mg/kg · PO, IV · q12h
As a prokinetic agent to stimulate colonic motility · 1-2 mg/kg · PO · q8-12h
As a prokinetic agent to stimulate colonic motility · 1-2 mg/kg · PO · q12h
All uses · 2 mg/kg/day · IV · constant infusion · Not an effective acid suppressant in healthy cats.
All uses · 2.5 mg/kg · IV · Not specified · Not an effective acid suppressant in healthy cats.

Ferrets

For Helicobacter mustelae · 24 mg/kg · PO · q8-12h · 14 days · Uses Ranitidine bismuth citrate (must be compounded). Given with clarithromycin (12.5 mg/kg PO q8-12h).

Horses

Foals · 1.5 mg/kg IV q8h or 6.6 mg/kg PO q8h · IV, PO · q8h · Often used with omeprazole (4 mg/kg PO q24h).
Foals · 6.6 mg/kg IV q4h or 0.8-2.2 mg/kg IV four times a day; 5-10 mg/kg PO two to four times a day. · IV, PO · q4h or QID (IV); BID-QID (PO)

투여 경로

POIVIMSC

금기

Hypersensitivity to ranitidine
No specific contraindications available in the monograph

이상반응

Vomiting (associated with rapid IV boluses in small animals)
Pain at the injection site (IM administration)
Mental confusion (rare, documented in humans)
Headache (rare, documented in humans)
Agranulocytosis (rare)
Transient cardiac arrhythmias (if given too rapidly IV)
Cardiac arrhythmias (rare, typically with rapid IV)
Hypotension (rare, typically with rapid IV)

약물 상호작용

Acetaminophen · Ranitidine (dose-dependent) may inhibit acetaminophen metabolism.
Antacids · High doses may decrease the absorption of ranitidine; administer at least 2 hours apart. · moderate
Ketoconazole · Absorption of ketoconazole may be reduced secondary to increased gastric pH.
Itraconazole · Absorption of itraconazole may be reduced secondary to increased gastric pH.
Metoprolol · Ranitidine may increase metoprolol half-life and peak serum levels.
Nifedipine · Ranitidine may increase nifedipine AUC by 30%.
Propantheline · Delays the absorption but increases the peak serum level of ranitidine; relative bioavailability may be increased by 23%.
Vitamin B-12 · Long-term ranitidine use may reduce oral absorption of Vitamin B-12.
Sucralfate · May affect absorption; advisable to administer sucralfate 2 hours before H2 blockers · minor
Digoxin · Ranitidine may reduce absorption or effect; stagger oral doses by 2 hours · moderate
Metoclopramide · Ranitidine may reduce absorption or effect; stagger oral doses by 2 hours · moderate

모니터링

Clinical efficacy (resolution of clinical signs, improved appetite, absence of blood in feces/vomitus)
Endoscopic examination (if indicated for ulcer healing)
Serum ALT values (consider monitoring during high-dose, chronic IV therapy)
Resolution of gastrointestinal clinical signs
Heart rate and blood pressure (during IV administration)

과용량

Clinical experience with ranitidine overdosage is limited, but the drug has a wide margin of safety. * **Signs of Toxicity:** In laboratory animals, massive doses (225 mg/kg/day) have caused muscular tremors, vomiting, and rapid respirations. Single doses of 1 gram/kg in rodents were not fatal. * **Treatment:** Handle using standard protocols for oral drug ingestions (e.g., gastric decontamination if recent and appropriate). Treat clinical signs symptomatically and supportively. Hemodialysis and peritoneal dialysis can effectively remove ranitidine from the body.

VetSheet 약물 레퍼런스는 면허 수의 전문가를 위한 임상 의사결정 보조 도구이며, 전문적 판단이나 제조사의 최신 라벨을 대신하지 않습니다.