メラトニン
メラトニンは松果体から分泌される天然ホルモンで、主に睡眠・覚醒サイクルの調節に関与します。獣医療では、犬の脱毛症（脱毛症Xなど）、犬猫の睡眠・行動障害、フェレットの副腎疾患の補助治療などに使用されます。
作用機序: Melatonin is involved in the neuroendocrine control of photoperiod-dependent molting, hair growth, and pelage color. * **Hair Growth:** It stimulates winter coat growth; spring shedding occurs when melatonin levels decrease. The exact mechanism is unknown but may involve direct effects on the hair follicle or alteration of **prolactin** and/or **melanocyte-stimulating hormone (MSH)** secretion. * **Endocrine Effects:** Increases serum prolactin and growth hormone levels, and enhances the response to growth hormone-releasing hormone. Long-term use may decrease **luteinizing hormone (LH)**. * **Antioxidant:** Acts as a potent free radical scavenger.
動物種別の用量
- Sleep disorders (nocturnal activity) · 3-12 mg (total dose) · PO · q12-24h
- Suppression of estrus · 18 mg implant · SC · Once · Suppresses estrus for 2-4 months
- Reduction of gastric ulcers in young pigs · 5 mg/kg in feed · PO · Continuous in feed
- Adjunctive treatment of adrenal disease · 0.5-1 mg per ferret · PO · q24h (7-9 hours after sunrise) · Can also use 5.4 mg implant which releases over 3-4 months. Better response in fall/winter.
- Adjunctive treatment of adrenal disease · 1-2 mg per ferret · PO · q24h · Or use 5.4 mg implant. May cause excessive drowsiness in ferrets under 600 grams.
- Alopecia-X, canine pattern baldness, or recurrent flank alopecia (experimental) · One to four 12 mg implants SC. Retreatment may be necessary once or twice a year. Alternatively, 3-6 mg PO q8-12h. · SC/PO · q8-12h (PO) or 1-2 times/year (SC) · Recommend having owners sign a release form noting the 'experimental' nature of treatment.
- Canine recurrent flank alopecia or seasonal flank alopecia · 2-3 mg per dog (up to 10 mg used) · PO · q24h for 3-5 days weekly or monthly, or daily · Improvement usually seen in 1 month, maximal in 3 months
- Alopecia X · 3-6 mg (total dose) · PO · 2-3 times a day · 3 months · Neutering recommended initially. Treat until maximal response is noted and discontinue. Re-institute if signs recur.
- Color dilution alopecia · 1.5-6 mg · PO · 2-3 times a day · Stop when good re-growth occurs
- Alopecia-X · 3 mg-12 mg (depending on size) · PO · 2 to 3 times a day · At least 4 months
- Sleep disorders (nocturnal activity) · 3-6 mg (total dose) · PO · q12-24h
- Sleep aid, fears, and phobias · 0.1 mg/kg · PO · q8h
- Idiopathic vacuolar hepatopathy · 4-6 mg/day (total dose for dogs <= 15 kg) · PO · q24h · May improve liver enzymes and hepatic changes.
- Hair cycling disorders (e.g., Alopecia X, seasonal flank alopecia) · 3-6 mg · PO · q8h · 4-6 week trial · If no growth is noted after 4-6 weeks, discontinue. May need repeating next year for seasonal flank alopecia.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Pregnancy
- Sexually immature animals
- Hepatic insufficiency (in humans)
- No information available
有害事象
- Sedation or drowsiness
- Altered sex hormone secretion and fertility
- Sterile abscesses at subcutaneous implant sites
- No information available in monograph (generally well tolerated, may cause mild sedation)
薬物相互作用
- Benzodiazepines · Melatonin may potentiate sedative effects
- Succinylcholine · Melatonin may potentiate neuromuscular blocking effects
モニタリング
- Clinical efficacy (e.g., hair regrowth, improved sleep patterns)
- Hair regrowth (evaluate after 4-6 weeks of therapy)
過量投与
Little information is available; it is unlikely to cause significant morbidity after a single overdose. Treat symptomatically if profound sedation occurs.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。