Note: This document contains side effect information about dantrolene. Some of the dosage forms listed on this page may not apply to the brand name Dantrium.
Applies to dantrolene: oral capsule
Other dosage forms:
Oral route (Capsule)
Dantrolene may cause hepatotoxicity, and symptomatic hepatitis (fatal and nonfatal) has been reported at various dose levels. Risk of hepatic injury appears to be greater in patients taking a higher dosage, in females, in patients over 35 years old, and in patients taking additional medication(s). Monitor hepatic function, including frequent determination of SGOT or SGPT, during therapy. Discontinue therapy after 45 days if there is no observable benefit.
Along with its needed effects, dantrolene (the active ingredient contained in Dantrium) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Serious side effects are very rare when dantrolene is taken for a short time, for example, when it is used for a few days before, during, or after surgery or anesthesia to prevent or treat malignant hyperthermia. However, serious side effects may occur, especially when the medicine is taken for a long time.
Check with your doctor immediately if any of the following side effects occur while taking dantrolene:
Some side effects of dantrolene may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Applies to dantrolene: intravenous powder for injection, oral capsule
The more commonly reported adverse reactions have included loss of grip strength, leg weakness, drowsiness, dizziness, nausea, fatigue, diarrhea, thrombophlebitis, and injection site reactions.
Common (1% to 10%): Hepatotoxicity, liver function test abnormalities
Frequency not reported: Jaundice, hepatitis, hepatic dysfunction including fatal hepatic failure
Several reports of severe constipation and abdominal distention leading to functional obstruction have been reported. Diarrhea may be severe and may necessitate temporary withdrawal of therapy. If diarrhea recurs, therapy should probably be permanently discontinued.
Common (1% to 10%): Dysphagia, nausea, vomiting, abdominal pain
Uncommon (0.1% to 1%): Constipation
Rare (less than 0.1%): Intestinal obstruction
Frequency not reported: Abdominal cramps, anorexia, alteration of taste, gastrointestinal bleeding, gastric irritation, diarrhea
Postmarketing reports: Anaphylaxis
Common (1% to 10%): Infusion site pain
Postmarketing reports: Thrombophlebitis and tissue necrosis
Frequency not reported: Abnormal hair growth, acne-like rash, eczematoid eruption, sweating, urticaria, rash, erythema
Very common (10% or more): Somnolence (up to 17%), dysphonia (13%)
Common (1% to 10%): Headache, dizziness, seizure, lightheadedness, drooling
Frequency not reported: Mental depression, mental confusion, insomnia, nervousness
Frequency not reported: Incontinence, increased urinary frequency, urinary retention, hematuria, crystalluria, nocturia, difficult urination and/or urinary retention, difficult erection
Very common (10% or more): Flushing
Common (1% to 10%): Pericarditis, atrioventricular block, tachycardia
Uncommon (0.1% to 1%): Exacerbation of preexisting cardiac insufficiency
Frequency not reported: Bradycardia, labile blood pressure, erratic blood pressure, heart failure, phlebitis
Pulmonary edema has developed during treatment of malignant hyperthermia; the contributory effect of the diluent volume and mannitol in these cases is not known.
Common (1% to 10%): Pleural effusion with associated eosinophilia
Rare (0.01% to 0.1%): -or- Rare (less than 0.1%):
Frequency not reported: Feeling of suffocation, respiratory depression, respiratory failure, dyspnea
Postmarketing reports: Pulmonary edema
Common (1% to 10%): Muscular weakness, extremity pain
Frequency not reported: Myalgia, backache
Frequency not reported: Aplastic anemia, leukopenia, lymphocytic lymphoma, thrombocytopenia
Common (1% to 10%): Blurred vision
Frequency not reported: Visual disturbances, diplopia, excessive tearing
Common (1% to 10%): Feeling abnormal
Frequency not reported: Chills, fever, general malaise
Frequency not reported: Transient lowering of GFR and renal plasma flow following 8 weeks of oral therapy
Medically reviewed by BestRx Medical Team Last updated on 1/1/2020.
Source: Drugs.com Dantrium