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dantrolene sodium

FDA Box Warning

Drug may be hepatotoxic and should be used only for recommended conditions. Daily doses of 400 mg are less likely to cause fatal and nonfatal hepatitis than daily doses above 800 mg. Overt hepatitis is most common during months 3 and 12, but may occur at any time; females, patients older than age 35, and those receiving concurrent therapy are at higher risk. Use only in conjunction with liver monitoring. Monitor liver function at baseline and regularly during therapy. Discontinue drug if values are abnormal.

Use lowest possible effective dose. If no benefit occurs after 45 days, discontinue.


Relaxes skeletal muscle by affecting excitation-contraction coupling response at site beyond myoneural junction, probably by interfering with calcium release from sarcoplasmic reticulum


Capsules: 25 mg, 50 mg, 100 mg

Powder for injection: 20 mg/vial

Indications and dosages

Chronic spasticity resulting from upper motor neuron disorders, such as multiple sclerosis, cerebral palsy, or spinal cord injury

Adults: Initially, 25 mg P.O. daily, increased gradually in 25-mg increments, if needed, up to 100 mg two or three times daily, to a maximum dosage of 400 mg P.O. daily. Maintain dosage level for 4 to 7 days to gauge patient response.

Children: Initially, 0.5 mg/kg P.O. daily for 7 days, increased to 0.5 mg/kg P.O. t.i.d. for 7 days; then 1 mg/kg P.O. t.i.d. for 7 days; then 2 mg/kg t.i.d., as needed. Don't exceed 100 mg P.O. q.i.d.

Malignant hyperthermic crisis

Adults and children: Initially, 1 mg/kg by I.V. push, repeated as needed up to a cumulative dosage of 10 mg/kg/day

To prevent or minimize malignant hyperthermia in patients who require surgery

Adults and children: 4 to 8 mg/kg P.O. daily in three or four divided doses for 1 to 2 days before surgery; give last dose 3 to 4 hours before surgery. Or 2.5 mg/kg I.V. infused over 1 hour before anesthestics are given.

To prevent recurrence of malignant hyperthermic crisis

Adults: 4 to 8 mg/kg daily P.O. in four divided doses for up to 3 days after initial hyperthermic crisis

Off-label uses

• Heat stroke
• Neuroleptic malignant syndrome


• Active hepatic disease (oral form)
• Patients who use spasticity to maintain posture or balance (oral form)
• Breastfeeding


Use cautiously in:
• cardiac, hepatic, or respiratory dysfunction or impairment
• women (especially pregnant women)
• adults older than age 35
• children younger than age 5.


• For I.V. use, add 60 ml of sterile water for injection to each vial; shake until solution is clear. Protect from direct light and use within 6 hours.
• Give therapeutic or emergency dose by rapid I.V. push. Administer followup dose over 2 to 3 minutes.
• Prevent extravasation when giving I.V. Drug has high pH and causes tissue irritation.

Adverse reactions

CNS: dizziness, drowsiness, fatigue, malaise, weakness, confusion, depression, insomnia, nervousness, headache, light-headedness, speech disturbances, seizures

CV: tachycardia, blood pressure fluctuations, phlebitis, heart failure

EENT: double vision, excessive tearing

GI: nausea, vomiting, diarrhea, constipation, abdominal cramps, GI reflux and irritation, hematemesis, difficulty swallowing, anorexia, GI bleeding

GU: urinary frequency, dysuria, nocturia, urinary incontinence, hematuria, crystalluria, prostatitis

Hematologic: aplastic anemia, leukopenia, thrombocytopenia, lymphocytic lymphoma

Hepatic: hepatitis

Musculoskeletal: myalgia, backache

Respiratory: suffocating sensation, respiratory depression, pleural effusion with pericarditis

Skin: rash, urticaria, pruritus, eczemalike eruptions, sweating, photosensitivity, abnormal hair growth

Other: altered taste, chills, fever, edema


Drug-drug.CNS depressants: increased CNS depression

Estrogen: increased risk of hepatotoxicity

Verapamil (I.V.): cardiovascular collapse (when given with I.V. dantrolene)

Drug-diagnostic tests.Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen: increased values

Drug-behaviors.Alcohol use: increased CNS depression

Sun exposure: phototoxicity

Patient monitoring

• Obtain baseline liver function test results; monitor periodically during therapy.
• Monitor ECG, serum electrolytes, and urine output regularly.

With long-term oral therapy, monitor patient for signs and symptoms of hepatotoxicity. Be prepared to discontinue drug if these occur.
• Assess for muscle weakness, poor coordination, and reduced reflexes before and during therapy. Drug may weaken muscles and impair ambulation.

Patient teaching

Instruct patient receiving prolonged oral therapy to immediately report weakness, malaise, fatigue, nausea, rash, itching, severe diarrhea, bloody or black tarry stools, or yellowing of skin or eyes.
• Inform patient that drug may cause drowsiness, dizziness, or light-headedness.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.


(dan-troe-leen) ,


(trade name)


Therapeutic: skeletal muscle relaxants
Pregnancy Category: C


Oral: Treatment of spasticity associated with:
  • Spinal cord injury,
  • stroke,
  • cerebral palsy,
  • multiple sclerosis.
Prophylaxis of malignant hyperthermia. Intravenous: Emergency treatment of malignant hyperthermia.Management of neuroleptic malignant syndrome.


Acts directly on skeletal muscle, causing relaxation by decreasing calcium release from sarcoplasmic reticulum in muscle cells.
Prevents intense catabolic process associated with malignant hyperthermia.

Therapeutic effects

Reduction of muscle spasticity.
Prevention of malignant hyperthermia.


Absorption: 35% absorbed after oral administration.
Distribution: Unknown.
Metabolism and Excretion: Almost entirely metabolized by the liver.
Half-life: 8.7 hr.

Time/action profile (effects on spasticity)

PO1 wkunknown6–12 hr


Contraindicated in: No contraindications to IV form in treatment of hyperthermia; Lactation: LactationSituations in which spasticity is used to maintain posture or balance.
Use Cautiously in: Cardiac, pulmonary, or previous liver disease;Women and patients >35 yr (↑ risk of hepatotoxicity); Geriatric: Use lowest possible dose (may have ↑ risk of hepatotoxicity) Obstetric: Use only if benefit outweighs potential risk to fetus

Adverse Reactions/Side Effects

Central nervous system

  • drowsiness (most frequent)
  • muscle weakness (most frequent)
  • confusion
  • dizziness
  • headache
  • insomnia
  • malaise
  • nervousness

Ear, Eye, Nose, Throat

  • excessive lacrimation
  • visual disturbances


  • pleural effusions
  • respiratory depression


  • changes in BP
  • heart failure
  • tachycardia


  • hepatotoxicity (life-threatening)
  • diarrhea (most frequent)
  • anorexia
  • cramps
  • dysphagia
  • GI bleeding
  • nausea
  • vomiting


  • crystalluria
  • dysuria
  • frequency
  • erectile dysfunction
  • incontinence
  • nocturia


  • pruritus
  • sweating
  • urticaria


  • anemia
  • aplastic anemia
  • eosinophilia
  • leukopenia
  • thrombocytopenia


  • irritation at IV site
  • phlebitis


  • myalgia


  • anaphylaxis (life-threatening)
  • chills
  • drooling
  • fever


Drug-Drug interaction

Additive CNS depression with CNS depressants, including alcohol, antihistamines, opioid analgesics, sedative/hypnotics, and parenteral magnesium sulfate.↑ risk of hepatotoxicity with other hepatotoxic agents or estrogens.↑ risk of arrhythmias with verapamil.↑ neuromuscular blocking effects of vecuronium.Concomitant use of kava-kava, valerian, chamomile, or hops can ↑ CNS depression.


Oral (Adults) Spasticity—25 mg once daily for 7 days, then 25 mg 2 times daily for 7 days, then 50 mg 3 times daily for 7 days, then 100 mg 3 times daily; may ↑ to 100 mg 4 times daily, if needed. Prevention of malignant hyperthermia—4–8 mg/kg/day in 3–4 divided doses for 1–2 days before procedure, last dose 3–4 hr preop. Posthyperthermic crisis follow-up—4–8 mg/kg/day in 3–4 divided doses for 1–3 days after IV treatment.
Oral (Children >5 yr) Spasticity—0.5 mg/kg once daily for 7 days, then 0.5 mg/kg 3 times daily for 7 days, then 1 mg/kg 3 times daily for 7 days, then 2 mg/kg 3 times daily (not to exceed 400 mg/day). Prevention of malignant hyperthermia—4–8 mg/kg/day in 3–4 divided doses for 1–2 days before procedure, last dose 3–4 hr preop. Posthyperthermic crisis follow-up—4–8 mg/kg/day in 3–4 divided doses for 1–3 days after IV treatment.
Intravenous (Adults and Children) Treatment of malignant hyperthermia—at least 1 mg/kg (up to 3 mg/kg), continued until symptoms decrease or a cumulative dose of 10 mg/kg has been given. If symptoms reappear, dose may be repeated. Prevention of malignant hyperthermia—2.5 mg/kg before anesthesia.

Availability (generic available)

Capsules: 25 mg, 50 mg, 100 mg
Powder for injection: 20 mg/vial

Nursing implications

Nursing assessment

  • Assess bowel function periodically. Persistent diarrhea may warrant discontinuation of therapy.
  • Muscle Spasticity: Assess neuromuscular status and muscle spasticity before initiating and periodically during therapy to determine response.
  • Malignant Hyperthermia: Assess previous anesthesia history of all surgical patients. Also assess for family history of reactions to anesthesia (malignant hyperthermia or perioperative death).
    • Monitor ECG, vital signs, electrolytes, and urine output continuously when administering IV for malignant hyperthermia.
    • Monitor patient for difficulty swallowing and choking during meals on the day of administration.
  • Lab Test Considerations: Monitor liver function frequently during therapy. Liver function abnormalities (↑ AST, ALT, alkaline phosphatase, bilirubin, GGTP) may require discontinuation of therapy.
    • Evaluate renal function and CBC before and periodically during therapy in patients receiving prolonged therapy.

Potential Nursing Diagnoses

Impaired physical mobility (Indications)
Acute pain (Indications)
Risk for injury (Side Effects)


  • Oral: If gastric irritation becomes a problem, may be administered with food. Oral suspensions may be made by opening capsules and adding them to fruit juices or other liquids. Drink immediately after mixing.
    • Oral dose for spasticity should be divided into 4 doses/day.
    • Oral dose is not indicated for neuroleptic malignant syndrome.
  • Intravenous Administration
  • pH: No Data.
  • Diluent: Reconstitute each 20 mg with 60 mL of sterile water for injection (without a bacteriostatic agent). Shake until solution is clear. Solution must be used within 6 hr. Administer without further dilution. Protect diluted solution from direct light.Concentration: 0.333 mg/mL.
  • Rate: Administer each single dose by rapid continuous IV push through Y-tubing or 3-way stopcock. Follow immediately with subsequent doses as indicated. Medication is very irritating to tissues; observe infusion site frequently to avoid extravasation.
  • Intermittent Infusion: Prophylactic dose has been administered as an infusion.
  • Rate: Administer over 1 hr before anesthesia.
  • Y-Site Compatibility: acyclovir, paclitaxel, palonosetron
  • Y-Site Incompatibility: alemtuzumab, alfentanil, amikacin, aminophylline, amphotericin B colloidal, amphotericin B lipid complex, ampicillin, ampicillin/sulbactam, anidulafungin, argatroban, arsenic trioxide, ascorbic acid, atracurium, atropine, azathioprine, aztreonam, benztropine, bivalirudin, bleomycin, bumetanide, buprenorphine, butorphanol, caclium chloride, calcium gluconate, carmustine, caspofungin, cefoperazone, cefotaxime, cefotetan, cefoxitin, ceftazidime, ceftriaxone, cefuroxime, chloramphenicol, chlorpromazine, cisplatin, clindamycin, cyanocobalamin, cyclosporine, dactinomycin, daptomycin, dexamethasone, diazepam, diazoxide, digoxin, diltiazem, diphenhydramine, dobutamine, docetaxel, dopamine, doxorubicin liposome, doxycycline, enalaprilat, ephedrine, epinephrine, epoetin alfa, ertapenem, erythromycin, esmolol, etoposide, etoposide phosphate, famotidine, fenoldopam, fentanyl, fluconazole, fludarabine, folic acid, foscarnet, furosemide, ganciclovir, gemcitabine, gentamicin, glycopyrrolate, granisetron, haloperidol, heparin, hetastarch, hydralazine, hydrocortisone, hydromorphone, hydroxyzine, idarubicin, imipenem/cilastatin, indomethacin, insulin, irinotecan, isoproterenol, ketorolac, labetalol, leucovorin, lidocaine, linezolid, lorazepam, magnesium sulfate, mannitol, mechlorethamine, meperidine, metaraminol, methyldopate, methylprednisolone, metoclopramide, metoprolol, metronidazole, midazolam, milrinone, mitoxantrone, morphine, multivitamins, mycophenolate, nafcillin, nalbuphine, naloxone, nesiritide, nitroglycerin, nitroprusside, norepinephrine, octreotide, ondansetron, oxacillin, oxaliplatin, oxytocin, pamidronate, pancuronium, pantoprazole, papaverine, pemetrexed, penicillin G, pentamidine, pentazocine, pentobarbital, phenobarbital, phentolamine, phenylephrine, phenytoin, phytonadione, piperacillin/tazobactam, potassium acetate, potassium chloride, procainamide, prochlorperazine, proimethazine, propranolol, protamine, pyridoxime, ranitidine, sodium acetate, sodium bicarbonate, streptokinase, succinylcholine, sufentanil, tacrolimus, teniposide, theophylline, thiamine, thiotepa, ticarcillin/clavulanate, tigecycline, tirofiban, tobramycin, tolazoline, trimethoprim/sulfamethoxazole, vancomycin, vasopressin, vecuronium, verapamil, vinblastine, vinorelbine, voriconazole, zoledronic acid

Patient/Family Teaching

  • Advise patient not to take more medication than the amount prescribed, to minimize risk of hepatotoxicity and other side effects. If a dose is missed, do not take unless remembered within 1 hr. Do not double doses.
    • May cause dizziness, drowsiness, visual disturbances, and muscle weakness. Advise patient to avoid driving and other activities requiring alertness until response to drug is known. After IV dose for surgery, patients may experience decreased grip strength, leg weakness, light-headedness, and difficulty swallowing for up to 48 hr. Caution patients to avoid activities requiring alertness and to use caution when walking down stairs and eating during this period.
    • Advise patient to avoid taking alcohol or other CNS depressants concurrently with this medication.
    • Instruct patient to notify health care professional if rash; itching; yellow eyes or skin; dark urine; or clay-colored, bloody, or black, tarry stools occur or if nausea, weakness, malaise, fatigue, or diarrhea persists. May require discontinuation of therapy.
    • Advise patient to wear sunscreen and protective clothing to prevent photosensitivity reactions.
    • Emphasize the importance of follow-up exams to check progress in long-term therapy and blood tests to monitor for side effects.
  • Malignant Hyperthermia: Patients with malignant hyperthemia should carry identification describing disease process at all times.

Evaluation/Desired Outcomes

  • Relief of muscle spasm in musculoskeletal conditions. One wk or more may be required to see improvement; if there is no observed improvement in 45 days, the medication is usually discontinued.
  • Prevention of or decrease in temperature and skeletal rigidity in malignant hyperthermia.


a trademark for a skeletal muscle relaxant used in the treatment of malignant hyperthermia or malignant hyperpyrexia (dantrolene sodium).


A brand name for DANTROLENE.
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Procter & Gamble has established a solid commercial platform for Dantrium, and we believe that SpePharm has the strategy and resources to enhance the product's commercial and clinical value.
Paul Capital Healthcare, one of the largest dedicated healthcare investors globally, made an equity investment in SpePharm in August 2008, and provided additional non-dilutive financing for SpePharm to acquire the rights to Dantrium.
Proctor and Gamble Pharmaceuticals markets Dantrium for the treatment of spasticity in stroke, multiple sclerosis, cerebral palsy and spinal cord injury.