Dantrolene

DANTRIUM

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Pronunciation: DAN-troe-leen

Dantrolene ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Dantrolene ballicule

Dantrolene DANTRIUM mascot mnemonic cartoon — Visual mnemonic: Dantrolene mascot
**“Dan trampoline”**

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.

Dantrolene molecular structure (skeletal formula) — Molecular structure: Dantrolene

FDA-approved for

spasticity/malignant hyperthermia (~1974)

Off-label

neuroleptic malignant syndrome
serotonin syndrome with hyperthermia

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Potential for hepatotoxicity — symptomatic (fatal and non-fatal) hepatitis reported; risk rises with dose (esp. ≥800 mg/day), female sex, age >35 yr, and concomitant hepatotoxic drugs. Monitor hepatic function (SGOT/SGPT); discontinue if no benefit within 45 days; use lowest effective dose.

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

Available strengths

cap 25, 50, 100 mg
inj 20, 250 mg

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

Cost

Dantrolene (DANTRIUM)

What pharmacies pay · NADAC 9/30/26

Strength		#/mo	generic $	CostPlus
25 mg	cap	30 qd	$12.26/mo	offered
50 mg	cap	30 qd	$16.61/mo	offered
100 mg	cap	30 qd	$30.22/mo	offered
20 mg	inj	per unit		not offered
250 mg	inj	per unit		not offered

Generic entry2005

⚠ BOXED WARNING

Hepatotoxicity with chronic oral use

Classes and tags

Clinical profile

Therapeutic safety burden3 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability2 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

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.

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