Ergot Alkaloids in Pediatric Medicine
Ergot Alkaloids in Pediatric Medicine
Key Points
- Derived from fungus Claviceps purpurea
- Complex pharmacology affecting multiple receptor systems
- Limited but specific indications in pediatrics
- Requires careful monitoring due to safety profile
Available Agents
- Natural Ergot Alkaloids
- Ergotamine tartrate
- Ergonovine maleate
- Semi-synthetic Derivatives
- Dihydroergotamine (DHE)
- Methysergide
Pharmacological Properties
Mechanism of Action
- Receptor Activity
- 5-HT1B/1D receptor agonism
- Alpha-adrenergic effects
- Dopamine D2 receptor activity
- Norepinephrine modulation
- Vascular Effects
- Cranial vessel vasoconstriction
- Peripheral vasoconstriction
- Venous capacitance reduction
- Neurological Effects
- Inhibition of neurogenic inflammation
- Reduced CGRP release
- Modulation of pain pathways
Pharmacokinetics
- Absorption
- Variable oral bioavailability (ergotamine ~2%)
- Better absorption with nasal/parenteral routes
- First-pass metabolism significant
- Distribution
- High protein binding (>90%)
- Large volume of distribution
- Tissue accumulation possible
- Metabolism
- Hepatic via CYP3A4
- Multiple active metabolites
- Enterohepatic recirculation
Clinical Applications
Primary Indications
- Migraine Management
- Status migrainosus
- Refractory migraine
- Selected chronic cases
- Cluster Headache
- Acute treatment
- Bridge therapy
- Other Applications
- Orthostatic hypotension (selected cases)
- Diagnostic applications
Patient Selection
- Age Considerations
- Generally reserved for adolescents
- Limited data in young children
- Risk-benefit assessment crucial
- Clinical Factors
- Severity of condition
- Previous treatment failures
- Contraindications screening
Administration & Dosing
Dihydroergotamine (DHE)
- Intravenous Administration
- Initial: 0.5-1 mg, maximum 3 mg/day
- Frequency: Every 8 hours
- Duration: Maximum 5 days
- Nasal Spray
- Age ≥ 12 years: 0.5 mg/spray
- Maximum: 3 mg/24 hours
- Weekly limit: 4 mg
Ergotamine Preparations
- Oral/Sublingual
- Initial: 1-2 mg
- Maximum: 6 mg/attack
- Weekly limit: 10 mg
- Administration Guidelines
- Take at onset of attack
- Space doses appropriately
- Monitor cumulative dose
Safety & Monitoring
Adverse Effects
- Common Effects
- Nausea/vomiting
- Peripheral vasoconstriction
- Abdominal pain
- Local reactions
- Serious Complications
- Ergotism
- Fibrotic changes
- Peripheral ischemia
- Vasospastic events
Monitoring Requirements
- Baseline Assessment
- Cardiovascular evaluation
- Peripheral vascular status
- Liver function tests
- Blood pressure measurement
- Ongoing Monitoring
- Peripheral pulses
- Signs of vasoconstriction
- Medication overuse
- Cumulative dosing
Contraindications
- Absolute
- Peripheral vascular disease
- Coronary artery disease
- Uncontrolled hypertension
- Sepsis
- Pregnancy
- Relative
- Raynaud's phenomenon
- Liver dysfunction
- Renal impairment
Drug Interactions
- Major Interactions
- CYP3A4 inhibitors
- Beta blockers
- Triptans
- Macrolide antibiotics
- Monitoring Points
- Enhanced vasoconstrictive effects
- Increased ergot toxicity risk
- Combination restrictions
