Methocarbamol
ROBAXIN
Pronunciation: meth-oe-KAR-ba-moel
“Metal Carl Row-backs in”
muscles → muscle relaxant
What it isCentral muscle relaxant of uncertain mechanism; acute musculoskeletal spasm.
Why this oneLess antimuscarinic than cyclobenzaprine, making it pragmatic when cognitive and urinary effects matter.
What limits itSedation, dizziness and weak efficacy limit benefit; warn that urine discoloration can occur.
Methocarbamol prescription history
Animated chart of estimated U.S. prescriptions per year, Muscle relaxants (1950–2026). Methocarbamol enters in 1957 (estimated).
FDA-approved for
- muscle spasm (~1957)
Principal riskSedation
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Musculoskeletal conditions (adjunct) | adult | 1500 mg QID (500 mg tab x3) or 1500 mg QID (750 mg tab x2) | ~4 g/day (500 mg: 1000 mg QID; 750 mg: 750 mg q4h or 1500 mg TID) | 8 g/day (severe conditions) |
Renal Undefined
Hepatic Undefined
Instructions
- 6 g/day for first 48-72 hours (up to 8 g/day for severe conditions), then reduce to ~4 g/day
Available strengths
- tab 500, 750, 1000 mg
- sol 1 g/10 mL
- susp 750 mg/5 mL
- inj 100 mg/mL
Cautions
- Anaphylactic reaction, angioneurotic edema
- Hypersensitivity reactions
- Seizures (including grand mal)
- Sedation/drowsiness — may impair mental/physical abilities
- Leukopenia
- Jaundice (incl. cholestatic)
Adverse reactions
- Drowsiness, dizziness, lightheadedness
- Nausea, vomiting, dyspepsia
- Blurred vision, headache
- Bradycardia, hypotension, syncope, flushing
- Rash, urticaria, pruritus
- Metallic taste, nasal congestion
Pregnancy Category C; reports of fetal/congenital abnormalities; avoid in women who are or may become pregnant unless benefit outweighs risk
Lactation Undefined
Cost
Generic entry1982
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Memory aids: interaction avatars
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Self-check
- What antimuscarinic advantage does methocarbamol have over cyclobenzaprine?
Less antimuscarinic activity. - What urine change should patients be warned about with methocarbamol?
Urine discoloration.