Dantrolene
DANTRIUM
What it isRyanodine receptor antagonist blocking sarcoplasmic calcium release; malignant hyperthermia, neuroleptic malignant syndrome and spasticity.
Why this oneIt is the only specific antidote for malignant hyperthermia and acts directly on muscle rather than the CNS.
What limits itDose-related hepatotoxicity with chronic oral use. Muscle weakness limits its use in spasticity.
FDA-approved for
- spasticity/malignant hyperthermia (~1974)
Off-label
- neuroleptic malignant syndrome
- serotonin syndrome with hyperthermia
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Chronic spasticity (e.g., spinal cord injury, stroke, cerebral palsy, MS) | Adults | 25 mg QD × 7 d | 25 mg TID → 50 mg TID → 100 mg TID (each level 7 d) | 100 mg QID |
| Chronic spasticity | Pediatrics | 0.5 mg/kg QD × 7 d | 0.5 mg/kg TID → 1 mg/kg TID → 2 mg/kg TID (each level 7 d) | 100 mg QID |
| Malignant hyperthermia — preoperative | Adults & pediatrics | 4–8 mg/kg/day in 3–4 divided doses × 1–2 d pre-op (last dose 3–4 h before surgery) | ||
| Malignant hyperthermia — post-crisis follow-up | Adults & pediatrics | 4–8 mg/kg/day in 4 divided doses × 1–3 d |
Titration Spasticity: maintain each dose level for 7 days before increasing
Renal Undefined
Hepatic Contraindicated in active hepatic disease (hepatitis, cirrhosis)
Instructions
- Discontinue if no observable benefit within 45 days
- Prescribe the lowest effective dose
Contraindications
- Active hepatic disease (hepatitis, cirrhosis)
- Where spasticity is used to sustain upright posture/balance or to maintain function
Cautions
- Hepatotoxicity — monitor SGOT/SGPT (see Boxed)
- Drowsiness/dizziness — additive CNS depression
- Severe diarrhea may require withdrawal
- Not indicated for neuroleptic malignant syndrome
Adverse reactions
- Drowsiness, dizziness, weakness, malaise, fatigue
- Diarrhea
- Hepatitis
- GI disturbances (nausea, cramps)
Pregnancy Adequate animal studies not conducted; use only if clearly needed
Lactation Undefined
⚠ BOXED WARNING
- Hepatotoxicity with chronic oral use
Cost, est. cash$10–$300/month
Generic entry2005
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
Mechanism of action: Dantrolene ballicule
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Memory aids: mascots and interaction avatars
