Two medicines, side by side
Carisoprodol vs tizanidine
Carisoprodol and tizanidine are both labeled for muscle spasms and spasticity. Drugs@FDA records approvals of carisoprodol since 1959 and of tizanidine since 1996. Pharmacies paid $0.0706 per carisoprodol 350 mg tablet and $0.0331 per tizanidine HCl 4 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, carisoprodol is a muscle relaxant and tizanidine a central alpha-2 adrenergic agonist.
Check it at the source: the carisoprodol FDA label on DailyMed (effective July 15, 2025); the tizanidine FDA label on DailyMed (effective January 2, 2026).
Highlights of the carisoprodol record
Carisoprodol (Soma) · label of July 15, 2025
Used for
From the label: indicationsCarisoprodol tablets are indicated for the relief of discomfort associated with acute, painful musculoskeletal conditions in adults. […]
On the market
- Earliest approval on file
- April 9, 1959
- Generic labelers
- 24 labelers
- Pharmacy cost
- $0.0706 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 5
Highlights of the tizanidine record
Tizanidine (Zanaflex) · label of January 2, 2026
Used for
From the label: indicationsZanaflex is indicated for the treatment of spasticity in adults. Zanaflex is a central alpha-2-adrenergic agonist indicated for the treatment of spasticity.
On the market
- Earliest approval on file
- November 27, 1996
- Generic labelers
- 49 labelers
- Pharmacy cost
- $0.0331 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 9
Source: FDA drug labels via openFDA (Carisoprodol label of July 15, 2025, Tizanidine label of January 2, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do carisoprodol and tizanidine differ on the record?
In FDA's classes, carisoprodol is a muscle relaxant and tizanidine a central alpha-2 adrenergic agonist.
How each works, in its label's words: Carisoprodol, “The mechanism of action of carisoprodol in relieving discomfort associated with acute painful musculoskeletal conditions has not been clearly identified.”; Tizanidine, “Tizanidine is a central alpha-2-adrenergic receptor agonist and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons.”
Half-life, in each label's words: Carisoprodol, “Excretion Carisoprodol is eliminated by both renal and non-renal routes with a terminal elimination half-life of …”; Tizanidine, “Elimination Metabolism Tizanidine has a half-life of approximately 2.5 hours (CV=33%).”
Generics: carisoprodol since 1979; tizanidine since 2002 (Drugs@FDA).
DEA schedule: carisoprodol CIV; tizanidine none.
| Carisoprodol | Tizanidine | |
|---|---|---|
| Labeled for | Muscle spasms and spasticity | Muscle spasms and spasticity |
| Pharmacologic class | Muscle Relaxant | Central alpha-2 Adrenergic Agonist |
| How it works (label) | The mechanism of action of carisoprodol in relieving discomfort associated with acute painful musculoskeletal conditions has not been clearly identified. | Tizanidine is a central alpha-2-adrenergic receptor agonist and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. The effects of tizanidine are greatest on polysynaptic pathways. |
| Half-life (label) | Excretion Carisoprodol is eliminated by both renal and non-renal routes with a terminal elimination half-life of approximately 2 hours. | Elimination Metabolism Tizanidine has a half-life of approximately 2.5 hours (CV=33%). |
| Earliest approval on file (Drugs@FDA) | April 9, 1959 | November 27, 1996 |
| First generic approved | June 12, 1979 | June 27, 2002 |
| Generic labelers (NDC) | 24 labelers | 49 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0706 per tablet (Carisoprodol 350 mg tablet) | $0.0331 per tablet (Tizanidine HCl 4 mg tablet) |
| 12-month price change | +3% | -12% |
| Boxed warning | No | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 5 | 9 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 18,964 | 41,179 |
| DEA schedule | CIV | 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 next?
- Alternatives to carisoprodol
- every medicine labeled for the same conditions