Two medicines, side by side
Dantrolene vs methocarbamol
Dantrolene and methocarbamol are both labeled for muscle spasms and spasticity. Drugs@FDA records approvals of dantrolene since 1974 and of methocarbamol since 1957. Pharmacies paid $0.409 per dantrolene sodium 25 mg capsule and $0.0395 per methocarbamol 500 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, dantrolene is a skeletal muscle relaxant and methocarbamol a muscle relaxant.
Check it at the source: the dantrolene FDA label on DailyMed (effective August 21, 2026); the methocarbamol FDA label on DailyMed (effective March 17, 2026).
Highlights of the dantrolene record
Dantrolene (Ryanodex) · label of August 21, 2026
Dantrolene sodium has a potential for hepatotoxicity, and should not be used in conditions other than those recommended. Symptomatic hepatitis (fatal and non-fatal) has been reported at various dose levels of the drug. The incidence reported in patients taking up to 400 mg/day is much lower than in those taking doses of 800 mg or more per day. Even sporadic short courses of these higher dose levels within a treatment regimen markedly increased the risk of serious hepatic injury.
Used for
From the label: indicationsIn Chronic Spasticity: Dantrolene sodium is indicated in controlling the manifestations of clinical spasticity resulting from upper motor neuron disorders (e.g., spinal cord injury, stroke, cerebral palsy, or multiple sclerosis). It is of particular benefit to the patient whose functional rehabilitation has been retarded by the sequelae of spasticity. […]
On the market
- Earliest approval on file
- January 15, 1974
- Generic labelers
- 10 labelers
- Pharmacy cost
- $0.409 per capsule
Supply and safety
- Shortage
- No current entry
- Recalls
- 3
Highlights of the methocarbamol record
Methocarbamol (Robaxin) · label of March 17, 2026
Used for
From the label: indicationsMethocarbamol is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of methocarbamol has not been clearly identified, but may be related to its sedative properties. Methocarbamol does not directly relax tense skeletal muscles in man.
On the market
- Earliest approval on file
- July 16, 1957
- Generic labelers
- 65 labelers
- Pharmacy cost
- $0.0395 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 6
Source: FDA drug labels via openFDA (Dantrolene label of August 21, 2026, Methocarbamol label of March 17, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do dantrolene and methocarbamol differ on the record?
In FDA's classes, dantrolene is a skeletal muscle relaxant and methocarbamol a muscle relaxant.
Half-life, in each label's words: Dantrolene, “The mean biologic half-life of dantrolene sodium in adults is 8.7 hours after a 100-mg dose.”; Methocarbamol, “Pharmacokinetics In healthy volunteers, the plasma clearance of methocarbamol ranges between 0.20 and 0.80 L/h/kg, the …”
Only the dantrolene label carries a boxed warning.
Generics: dantrolene since 2005; methocarbamol since 1974 (Drugs@FDA).
| Dantrolene | Methocarbamol | |
|---|---|---|
| Labeled for | Muscle spasms and spasticity | Muscle spasms and spasticity |
| Pharmacologic class | Skeletal Muscle Relaxant | Muscle Relaxant |
| How it works (label) | n/a | of methocarbamol in humans has not been established, but may be due to general central nervous system (CNS) depression. It has no direct action on the contractile mechanism of striated muscle, the motor end plate or the nerve fiber. |
| Half-life (label) | The mean biologic half-life of dantrolene sodium in adults is 8.7 hours after a 100-mg dose. | Pharmacokinetics In healthy volunteers, the plasma clearance of methocarbamol ranges between 0.20 and 0.80 L/h/kg, the mean plasma elimination half-life ranges between 1 and 2 hours, and the plasma protein binding … |
| Earliest approval on file (Drugs@FDA) | January 15, 1974 | July 16, 1957 |
| First generic approved | March 1, 2005 | October 22, 1974 |
| Generic labelers (NDC) | 10 labelers | 65 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.409 per capsule (Dantrolene sodium 25 mg capsule) | $0.0395 per tablet (Methocarbamol 500 mg tablet) |
| 12-month price change | +3% | +6% |
| Boxed warning | Yes | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 3 | 6 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 1,745 | 22,591 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What do the labels say about using others of their kind?
Methocarbamol label, warningsWARNINGS Since methocarbamol may possess a general CNS depressant effect, patients receiving methocarbamol tablets should be cautioned about combined effects with alcohol and other CNS depressants.
Source: FDA drug labels via openFDA
What next?
- Alternatives to dantrolene
- every medicine labeled for the same conditions