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ピリドスチグミン

Pyridostigmine

Pyridostigmine bromide

抗コリンエステラーゼ薬POIVIM犬猫

別名: Mestinon · Distinon · Kalymin · Regonol · pyridostigmini bromidum · Pyridostigmine bromide

VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス

0.5-3 mg/kg PO q8-12 hours with food.PO· q8-12h
— 🐕

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

動物種別用量

🌎 NA — North America🌍 EU — Europe

犬

適応用量経路頻度期間地域
Myasthenia gravis (MG)1-3 mg/kg PO q8-12h. For animals that cannot tolerate oral medications, it may be used as an IV constant rate infusion at 0.01-0.03 mg/kg/hour.PO/IVq8-12h or CRI—🌎 NA
Myasthenia gravis (MG)0.5-3 mg/kg PO q8-12 hours with food.POq8-12h—🌎 NA
Acquired Myasthenia gravis (MG)7.5-30 mg PO two times a day.POBID—🌎 NA
Myasthenia gravis (MG)0.5-3 mg/kg PO two to three times a day.POBID-TID—🌎 NA
Myasthenia gravis (MG)0.5-1 mg/kg PO two to three times a dayPOBID-TID—🌎 NA
Myasthenia gravis0.2-5 mg/kgPOq8-12h—🌍 EU
  • Myasthenia gravis (MG): Titrate to effect to minimize adverse effects and maximize muscle strength.
  • Myasthenia gravis (MG): Start low and increase slowly. Liquid formulation recommended for easy adjustment. An H2 antagonist (e.g., famotidine 5 mg/kg/day) may reduce nausea/GI irritation.
  • Acquired Myasthenia gravis (MG): Begin after oral regurgitation is abolished with parenteral neostigmine. Once stable, begin corticosteroids for 2 weeks, then gradually reduce pyridostigmine.
  • Myasthenia gravis (MG): If no response, add prednisone.
  • Myasthenia gravis (MG): With or without prednisone (2 mg/kg PO twice daily). Spontaneous remission is not uncommon.
  • Myasthenia gravis: Dose should be incrementally adjusted to maximize muscle strength and minimize adverse effects.

猫

適応用量経路頻度期間地域
Myasthenia gravis (MG)0.5-3 mg/kg daily PO in divided dosesPODivided daily—🌎 NA
Myasthenia gravis (MG)1-3 mg/kg PO q8-12hPOq8-12h—🌎 NA
Myasthenia gravis (MG)0.5-3 mg/kg PO per dayPODaily—🌎 NA
Myasthenia gravis0.25 mg/kgPOq8-12h—🌍 EU
  • Myasthenia gravis (MG): Dose depending on response.
  • Myasthenia gravis (MG): Given with corticosteroids.

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

診察中ですか？VetSheet の AI が薬剤・用量・投与期間を構造化された診察記録に直接記入します。VetSheet の仕組みを見る

概要

臭化ピリドスチグミンは合成第四級アンモニウム抗コリンエステラーゼ薬であり、獣医学では主に犬（まれに猫）の​重症筋無力症（MG）​の管理に使用されます。

  • ​臨床のポイント：​ 第四級アンモニウム構造を持つため、標準的な治療用量では血液脳関門を容易に通過しません。そのため、中枢神経系（CNS）の副作用を引き起こすことなく、MGのような末梢神経筋接合部疾患を標的とするのに理想的です。
  • 一般に、先天性のMGよりも​後天性重症筋無力症​に対してはるかに有効であると考えられています。
  • 吸収が不安定で治療域が狭いため、筋力の改善とコリン作動性毒性のリスクのバランスを取りながら、効果を見極めて慎重に用量を調整する必要があります。

作用機序

Pyridostigmine acts as a reversible, competitive inhibitor of the enzyme ​acetylcholinesterase (AChE)​ at the neuromuscular junction.

  • ​Mechanism:​ Pyridostigmine competes directly with ​acetylcholine (ACh)​ for attachment to AChE. The resulting pyridostigmine-AChE complex is hydrolyzed much more slowly than the natural ACh-AChE complex.
  • ​Pathway:​ Inhibition of AChE → Decreased breakdown of ACh → Accumulation of ACh in the synaptic cleft → Prolonged and increased stimulation of nicotinic ACh receptors on the motor endplate → Enhanced skeletal muscle contraction and improved strength in myasthenic patients.

安全性・警告

禁忌

  • Hypersensitivity to anticholinesterase compounds or bromides
  • Mechanical or physical obstructions of the urinary tract
  • Mechanical or physical obstructions of the gastrointestinal (GI) tract
  • Mechanical gastrointestinal obstruction
  • Mechanical urinary tract obstruction
  • Peritonitis

有害事象

  • Nausea
  • Vomiting
  • Diarrhea
  • Excessive salivation (ptyalism)
  • Sweating (in species with sweat glands)
  • Increased bronchial secretions
  • Bronchospasm
  • Pulmonary edema
  • Respiratory paralysis
  • Miosis (pupil constriction)
  • Blurred vision
  • Lacrimation (tearing)
  • Bradycardia
  • Tachycardia
  • Cardiospasm
  • Hypotension
  • Cardiac arrest
  • Muscle cramps
  • Weakness (can indicate cholinergic crisis)
  • Increased salivation (ptyalism)
  • Diarrhoea
  • Abdominal cramps
  • Bronchoconstriction
  • Involuntary defecation and micturition
  • Nystagmus
  • Heart block
  • Arrhythmias
  • Agitation
  • Muscle weakness
  • Fasciculations

注意事項

​High-Risk Patients:​ Use with extreme caution in patients with bronchospastic disease, epilepsy, hyperthyroidism, bradycardia or other arrhythmias, vagotonia, or GI ulcer diseases.

  • ​Pregnancy/Nursing:​ FDA Category C. Excreted in maternal milk; use with caution in nursing patients.
  • ​Dose Titration:​ Doses must be carefully titrated. High doses can cause a cholinergic crisis, which presents as profound weakness and can be difficult to distinguish from a myasthenic crisis.

医薬品相互作用

Atropine

Antagonizes the muscarinic effects of pyridostigmine. Use cautiously as it can mask early clinical signs of a life-threatening cholinergic crisis.

Corticosteroids

May decrease the anticholinesterase activity of pyridostigmine. Discontinuing corticosteroids may suddenly increase anticholinesterase activity, requiring dose adjustments.

Dexpanthenol

Theoretically may have additive cholinergic effects when used concurrently.

Neuromuscular blocking drugs (e.g., aminoglycosides)

May necessitate increased dosages of pyridostigmine when treating or diagnosing myasthenic patients.

Magnesium (parenteral)

Can antagonize anticholinesterase therapy due to its direct depressant effect on skeletal muscle.

Muscle Relaxants

May prolong the Phase I block of depolarizing muscle relaxants (e.g., succinylcholine) and antagonize the actions of non-depolarizing agents (e.g., pancuronium, atracurium).

AminoglycosidesModerate

May antagonize the neuromuscular effects of pyridostigmine

ClindamycinModerate

May antagonize the neuromuscular effects of pyridostigmine

LincomycinModerate

May antagonize the neuromuscular effects of pyridostigmine

PropranololModerate

May antagonize the effects of pyridostigmine

SuxamethoniumMajor

Pyridostigmine may enhance the effect of depolarizing muscle relaxants

PancuroniumMajor

Pyridostigmine antagonizes the effect of non-depolarizing muscle relaxants

VecuroniumMajor

Pyridostigmine antagonizes the effect of non-depolarizing muscle relaxants

監視

  • Clinical signs of cholinergic toxicity (salivation, lacrimation, urination, defecation, GI upset, emesis, weakness)
  • Efficacy of therapy (improvement in muscle strength, reduction of megaesophagus/regurgitation)
  • Improvement in muscle strength and exercise tolerance
  • Signs of muscarinic toxicity (hypersalivation, vomiting, diarrhea, miosis)
  • Heart rate and rhythm
  • Respiratory rate and effort (especially in patients with megaoesophagus)

薬物動態

吸収

Marginally absorbed from the GI tract. Absorption may be erratic, especially with sustained-release tablets. Onset of action after oral dosing is generally within one hour.

分布

Distributed to most tissues, but does not cross into the brain (CNS), intestinal wall, fat, or thymus at usual doses due to its quaternary ammonium structure. Crosses the placenta.

代謝

Metabolized by the liver and hydrolyzed by cholinesterases.

消失

Excreted primarily via the kidneys (implied by class, though specific veterinary elimination data is sparse in the monograph).

過剰投与

Overdosage of pyridostigmine can induce a life-threatening cholinergic crisis.

  • ​Clinical Signs (SLUDGE syndrome):​ GI effects (nausea, vomiting, diarrhea), excessive salivation, sweating, respiratory distress (increased bronchial secretions, bronchospasm, pulmonary edema, respiratory paralysis), ophthalmic effects (miosis, blurred vision, lacrimation), cardiovascular collapse (bradycardia, tachycardia, hypotension, cardiac arrest), severe muscle cramps, and profound weakness.
  • ​Diagnostic Challenge:​ Overdoses in myasthenic patients can be very difficult to distinguish from a myasthenic crisis (disease exacerbation). The time of onset of clinical signs or an edrophonium challenge (Tensilon test) may help differentiate the two.
  • ​Treatment:​ Consists of immediate respiratory and cardiac supportive therapy. Atropine should be administered to antagonize muscarinic effects (refer to atropine protocols for cholinergic toxicity).

製品

製剤

  • Extended-release tablets
  • Injection
  • 60 mg tablets
  • 60 mg/5 ml oral syrup (available on import licence)

ヒト用医薬品

  • Pyridostigmine Bromide Tablets: 60 mg (Mestinon®, generic)
  • Pyridostigmine Bromide Extended-Release Tablets: 180 mg (Mestinon®)
  • Pyridostigmine Bromide Syrup: 12 mg/mL in 480 mL (Mestinon®)
  • Pyridostigmine Bromide Injection: 5 mg/mL in 2 mL ampules (Mestinon®)
  • Mestinon 60 mg tablets

規制ステータス

European Union✓ 承認済み処方箋医薬品EMA
🐕 Dogs🐈 Cats

Human registered products often used under the cascade.

United Kingdom✓ 承認済み処方箋医薬品VMD
🐕 Dogs🐈 Cats

POM (Prescription Only Medicine). Oral syrup available on import licence.

規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Store products at room temperature unless otherwise instructed. Protect oral solution and injection from light and freezing. Keep tablets in tight containers. Extended-release tablets may become mottled over time, but this does not affect potency. Injection is unstable in alkaline solutions.

飼主向け情報

ピリドスチグミンはペットの重症筋無力症を管理するための重要な薬ですが、用量は非常に正確である必要があります。

  • ​厳密な投薬：​ 獣医師の指示通りに正確に投薬してください。有効量と中毒量の差が非常に小さいため、相談なしに用量を変更しないでください。
  • ​投与方法：​ 食事と一緒に与えることで、胃腸の不調を軽減できる場合があります。微細な用量調整を可能にするため、液体製剤が好まれることがよくあります。
  • ​毒性の観察：​ 過剰よだれ、嘔吐、下痢、極度の脱力感、筋肉のけいれん、呼吸困難などの過剰摂取の兆候に気づいた場合は、​直ちに​獣医師に連絡してください。
  • ​自然寛解：​ 一部の犬では、重症筋無力症が時間の経過とともに自然に治癒することがあるため、獣医師はペットの状態を注意深く監視し、最終的に薬を減らしたり中止したりできるかを確認します。

VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。