Meds and you

Updated 11 February 2013

Dantrolene

Dantrolene is a muscle relaxant; it is prescribed in the treatment of muscle spasm such as those encountered in conditions like cerebral palsy and multiple sclerosis.

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Dantrolene is the active ingredient of Dantrium.

General Information

Dantrolene is a muscle relaxant; it is prescribed in the treatment of muscle spasm such as those encountered in conditions like cerebral palsy, multiple sclerosis and spinal cord injury.

Importantly, dantrolene is the only specific and effective treatment for malignant hyperthermia, a rare, often hereditary, life-threatening condition, that is triggered by exposure to inhalation of anaesthetics such as enflurane and halothane during or after surgery. Symptoms of this condition include a rapid rise in heart rate, severe muscle rigidity and/or an increased body temperature that often exceeds 43° Celsius. If left untreated, death may result.

This medication may cause the skin to be more sensitive towards sunlight - It is advisable to minimise sun exposure.

How does dantrolene work?

Dantrolene works by directly affecting the ability of your muscles to contract. Spasms, and the increase in muscle metabolism that results in malignant hyperthermia, is the result of a massive increase in calcium release from skeletal muscle cells. Dantrolene reduces the release of this calcium.

Fast facts

Drug schedule: Schedule 4

Available as: Dantrolene is available as capsules and injection.

What does it do? Dantrolene has a muscle-relaxing effect

Overdose risk: Medium

Dependence risk: Low

Is dantrolene available as a generic? No

Is dantrolene available on prescription only? Yes

User information

Onset of effect: Depends on condition being treated

Duration of action: Depends on condition being treated

Dietary advice : If oral form, each dose should be taken with a full glass of water.

Stopping this medicine: Use this medication strictly as directed by prescriber. Do not discontinue without speaking to your doctor.

Prolonged use: Prolonged use may be associated with undesirable side effects; liver function needs to be tested at regular intervals.

Special precautions

Consult your doctor before using this drug if:

  • you have liver disease
  • you have heart disease
  • you have a lung or breathing condition
  • you are allergic to dantrolene
  • you are taking other medication.

Pregnancy: Avoid. It is unknown how this medication may affect your baby. Consult your doctor before using this drug, or if you are planning to fall pregnant.

Breastfeeding: Avoid. It is unknown how this medication may affect your baby. Consult your doctor before use.

Porphyria: Avoid. This medication may cause serious adverse effects. Consult your doctor before use.

Infants and children: Safety and efficacy of this medication has not been established for children under the age of 5.

Elderly: Use with caution, as side-effects may be more likely.

Driving and hazardous work: Caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.

Alcohol: Avoid concomitant use of alcohol with this medication as it may increase drowsiness and dizziness while taking dantrolene.

Possible side effects

Side effect

Frequency

Consult your doctor

Common

Rare

Only if severe

In all cases

Drowsiness, dizziness

x

x

Diarrhoea, constipation

x

x

Abnormal vision

x

x

Headache

x

x

Confusion

x

x

Decreased appetite

x

x

Difficulty breathing

x

x

Rash

x

Jaundice

x

x

Convulsions

x

x

Interactions

Drug interactions

Calcium-channel blockers (Verapamil)

Risk of cardiovascular collapse

Alcohol, benzodiazepines, antihistamines and other drugs that may cause sedation

Increased risk of sedation

Metoclopramide

Increased levels of dantrolene; risk of toxicity

Oestrogens

Increased risk of liver damage

Disease interactions

Consult your doctor before using this drug if you have liver disease, heart disease, a lung or breathing condition, or if you are allergic to dantrolene.

Overdose action

An overdose of this medication can be serious. Seek immediate emergency medical attention.

Recommended dosage

Malignant hyperthermia: 1 mg/kg until muscle tone is reduced, body temperature lowered and heart rate has slowed down. (Maximum 10 mg/kg)

 

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