← All drugs
Drug · FAERS side-effect profile with label screen

Methocarbamol side effects: what 22,550 FDA adverse event reports show

Methocarbamol · 1,165 reaction terms · 103,879 drug–reaction co-reports · data 2026-09-14
Share: X Facebook Reddit Email

Drug class

Muscle Relaxant

FDA label (Established Pharmacologic Class) · compare the class

Who reports

22,550 reports · 62% serious · 1,735 with death outcome · 70% female

openFDA FAERS counts, all years, deduplication not applied

Used for

The injectable form of methocarbamol 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 this drug has not been clearly identified, but may be related to its sedative properties. Methocarbamol does not directly relax tense skeletal muscles in man.

FDA label, Indications and Usage

What it is

DESCRIPTION Methocarbamol Injection, USP a carbamate derivative of guaifenesin, is a central nervous system (CNS) depressant with sedative and musculoskeletal relaxant properties. It is a sterile, pyrogen-free solution intended for intramuscular or intravenous administration.

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Reporting / coding artifact 5Not in label — unassessed 35
What the badges mean

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only (and, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,125 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show:
ReactionReportsPRR 95% CI · ROR · χ²/pEBGM EB05 · IC025Label screenSerious-only & strataTrial cross-check
Amyloid arthropathy28712.3
434.8–1,167.0ROR 713.2 · calibrated p 4e-14 ✓
314.8 EB05 228.6 · IC025 +5.0
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.4–6.8)
Not in label — unassessedserious n=28 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Child abuse42187.6
134.7–261.4ROR 188.0 · calibrated p 2e-9 ✓
145.7 EB05 112.3 · IC025 +5.3
3/3 methods agree
vs other Muscle Relaxants: PRR 4.1 (2.7–6.3)
Reporting / coding artifactserious n=42 · ♀ 0% (drug 70%) · 100% clinicianno trial data cached
Epidural lipomatosis43130.8
95.1–180.0ROR 131.1 · calibrated p 3e-8 ✓
109.2 EB05 84.4 · IC025 +5.1
3/3 methods agree
vs other Muscle Relaxants: PRR 4.1 (2.7–6.3)
Not in label — unassessedserious n=43 · ♀ 0% (drug 70%) · 100% clinicianno trial data cached
Victim of child abuse28118.7
80.1–176.0ROR 118.9 · calibrated p 9e-8 ✓
98.3 EB05 71.4 · IC025 +4.6
3/3 methods agree
vs other Muscle Relaxants: PRR 4.1 (2.4–7.0)
Reporting / coding artifactserious n=28 · ♀ 0% (drug 70%) · 100% clinicianno trial data cached
Jaw clicking1892.1
56.7–149.5ROR 92.2 · calibrated p 9e-7 ✓
77.2 EB05 51.6 · IC025 +3.9
3/3 methods agree
vs other Muscle Relaxants: only this drug
Not in label — unassessedserious n=18no trial data cached
Multiple drug therapy4361.0
44.8–83.0ROR 61.1 · calibrated p 6e-6 ✓
55.9 EB05 43.2 · IC025 +4.6
3/3 methods agree
vs other Muscle Relaxants: PRR 4.4 (2.9–6.8)
Reporting / coding artifactserious n=42 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Necrosis ischaemic2655.2
37.2–82.1ROR 55.3 · calibrated p 1e-5 ✓
50.4 EB05 36.1 · IC025 +4.1
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.3–6.9)
Not in label — unassessedserious n=26 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Chronic kidney disease-mineral and bone disorder4237.7
27.7–51.3ROR 37.8 · calibrated p 1e-4 ✓
35.7 EB05 27.5 · IC025 +4.2
3/3 methods agree
vs other Muscle Relaxants: PRR 2.3 (1.6–3.3)
Not in label — unassessedserious n=42no trial data cached
Gallbladder polyp2429.4
19.6–44.2ROR 29.5 · calibrated p 5e-4 ✓
28.0 EB05 19.8 · IC025 +3.5
3/3 methods agree
vs other Muscle Relaxants: only this drug
Not in label — unassessedserious n=24 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Myofascial pain syndrome1824.0
15.0–38.3ROR 24.0 · calibrated p 0.001 ✓
22.9 EB05 15.2 · IC025 +3.1
3/3 methods agree
vs other Muscle Relaxants: PRR 3.4 (1.8–6.4)
Not in label — unassessedserious n=18no trial data cached
Hepatitis viral2023.8
15.2–37.0ROR 23.8 · calibrated p 0.001 ✓
22.7 EB05 15.5 · IC025 +3.2
3/3 methods agree
vs other Muscle Relaxants: only this drug
Not in label — unassessedserious n=20no trial data cached
Hyperparathyroidism secondary6323.7
18.5–30.4ROR 23.7 · calibrated p 0.001 ✓
23.0 EB05 18.6 · IC025 +3.9
3/3 methods agree
vs other Muscle Relaxants: PRR 2.7 (2.0–3.8)
Not in label — unassessedserious n=63 · ♀ 46% (drug 70%)no trial data cached
Rebound acid hypersecretion7623.6
18.8–29.6ROR 23.7 · calibrated p 0.001 ✓
22.9 EB05 18.9 · IC025 +4.0
3/3 methods agree
vs other Muscle Relaxants: PRR 2.6 (1.9–3.4)
Not in label — unassessedserious n=76no trial data cached
Nephrogenic anaemia11523.4
19.5–28.2ROR 23.5 · calibrated p 0.001 ✓
22.8 EB05 19.5 · IC025 +4.1
3/3 methods agree
vs other Muscle Relaxants: PRR 2.6 (2.0–3.2)
Not in label — unassessedserious n=115no trial data cached
Pneumonia streptococcal2723.4
16.0–34.3ROR 23.4 · calibrated p 0.001 ✓
22.5 EB05 16.2 · IC025 +3.4
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.3–6.8)
Not in label — unassessedserious n=27 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Acquired haemophilia2120.2
13.1–31.1ROR 20.2 · calibrated p 0.003 ✓
19.4 EB05 13.2 · IC025 +3.0
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.2–7.3)
Not in label — unassessedserious n=21no trial data cached
Beta haemolytic streptococcal infection2619.6
13.3–28.9ROR 19.7 · calibrated p 0.003 ✓
19.0 EB05 13.5 · IC025 +3.2
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.3–6.9)
Not in label — unassessedserious n=26 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Bone demineralisation2118.7
12.2–28.8ROR 18.7 · calibrated p 0.004 ✓
18.0 EB05 12.2 · IC025 +3.0
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (2.2–7.3)
Not in label — unassessedserious n=18no trial data cached
Distributive shock4318.4
13.6–24.9ROR 18.5 · calibrated p 0.004 ✓
17.9 EB05 13.8 · IC025 +3.4
3/3 methods agree
vs other Muscle Relaxants: PRR 2.9 (2.0–4.3)
Not in label — unassessedserious n=43 · ♀ 100% (drug 70%) · 100% clinicianno trial data cached
Lumbar radiculopathy2117.0
11.0–26.2ROR 17.0 · calibrated p 0.006 ✓
16.3 EB05 10.9 · IC025 +2.9
3/3 methods agree
vs other Muscle Relaxants: PRR 2.6 (1.5–4.6)
Not in label — unassessedserious n=19no trial data cached
Juvenile idiopathic arthritis4417.0
12.6–22.9ROR 17.0 · calibrated p 0.005 ✓
16.5 EB05 12.8 · IC025 +3.3
3/3 methods agree
vs other Muscle Relaxants: PRR 4.2 (2.7–6.4)
Not in label — unassessedserious n=44 · ♀ 0% (drug 70%) · 100% clinicianno trial data cached
Cervical spinal stenosis2714.7
10.1–21.5ROR 14.7 · calibrated p 0.010 ✓
14.1 EB05 9.9 · IC025 +2.9
3/3 methods agree
vs other Muscle Relaxants: PRR 3.4 (2.0–5.6)
Not in label — unassessedserious n=26 · ♀ 100% (drug 70%)no trial data cached
Product administration interrupted10613.0
10.7–15.7ROR 13.1 · calibrated p 0.013 ✓
12.7 EB05 10.8 · IC025 +3.3
3/3 methods agree
vs other Muscle Relaxants: PRR 4.0 (3.1–5.2)
Reporting / coding artifactserious n=95no trial data cached
Narcolepsy2613.0
8.8–19.1ROR 13.0 · calibrated p 0.016 ✓
12.3 EB05 8.5 · IC025 +2.7
3/3 methods agree
vs other Muscle Relaxants: PRR 2.7 (1.7–4.5)
Not in label — unassessedserious n=24no trial data cached
Pre-existing condition improved8612.8
10.4–15.9ROR 12.9 · calibrated p 0.014 ✓
12.5 EB05 10.4 · IC025 +3.2
3/3 methods agree
vs other Muscle Relaxants: PRR 2.5 (1.9–3.3)
Not in label — unassessedserious n=51no trial data cached
Essential hypertension3312.0
8.5–16.9ROR 12.0 · calibrated p 0.020 ✓
11.4 EB05 8.2 · IC025 +2.8
3/3 methods agree
vs other Muscle Relaxants: PRR 2.5 (1.6–3.8)
Not in label — unassessedserious n=31no trial data cached
Neck injury3711.8
8.5–16.3ROR 11.8 · calibrated p 0.021 ✓
11.2 EB05 8.3 · IC025 +2.8
3/3 methods agree
vs other Muscle Relaxants: PRR 2.7 (1.8–4.1)
Not in label — unassessedserious n=33 · 72% consumerno trial data cached
Spinal fusion surgery4911.5
8.6–15.2ROR 11.5 · calibrated p 0.022 ✓
11.0 EB05 8.5 · IC025 +2.9
3/3 methods agree
vs other Muscle Relaxants: PRR 3.2 (2.2–4.6)
Not in label — unassessedserious n=48no trial data cached
Obstructive sleep apnoea syndrome1711.4
7.1–18.5ROR 11.4 · calibrated p 0.027 ✓
10.2 EB05 6.3 · IC025 +2.3
3/3 methods agree
vs other Muscle Relaxants: only this drug
Not in label — unassessedserious n=14no trial data cached
Intervertebral disc degeneration11211.3
9.4–13.6ROR 11.4 · calibrated p 0.022 ✓
11.0 EB05 9.4 · IC025 +3.1
3/3 methods agree
vs other Muscle Relaxants: PRR 2.1 (1.7–2.7)
Not in label — unassessedserious PRR 10.6no trial data cached
Spinal cord injury2111.3
7.3–17.4ROR 11.3 · calibrated p 0.027 ✓
10.3 EB05 6.7 · IC025 +2.4
3/3 methods agree
vs other Muscle Relaxants: PRR 4.4 (2.4–8.2)
Not in label — unassessedserious n=21no trial data cached
Suspected suicide5711.2
8.7–14.6ROR 11.3 · calibrated p 0.023 ✓
10.8 EB05 8.5 · IC025 +2.9
3/3 methods agree
vs other Muscle Relaxants: PRR 2.6 (1.9–3.7)
Not in label — unassessedserious n=57 · 100% clinicianno trial data cached
Kyphosis2111.1
7.2–17.1ROR 11.1 · calibrated p 0.028 ✓
10.1 EB05 6.6 · IC025 +2.4
3/3 methods agree
vs other Muscle Relaxants: PRR 4.7 (2.5–8.8)
Not in label — unassessedserious n=21no trial data cached
Spinal osteoarthritis10411.1
9.1–13.4ROR 11.1 · calibrated p 0.023 ✓
10.8 EB05 9.1 · IC025 +3.1
3/3 methods agree
vs other Muscle Relaxants: PRR 2.5 (2.0–3.2)
Not in label — unassessedserious PRR 9.9no trial data cached
Infusion site discharge2011.0
7.1–17.1ROR 11.0 · calibrated p 0.030 ✓
9.9 EB05 6.4 · IC025 +2.4
3/3 methods agree
vs other Muscle Relaxants: PRR 4.2 (2.2–7.9)
Not in label — unassessedserious n=14no trial data cached
Radiculopathy3010.7
7.5–15.3ROR 10.7 · calibrated p 0.030 ✓
9.9 EB05 7.1 · IC025 +2.6
3/3 methods agree
vs other Muscle Relaxants: PRR 2.4 (1.5–3.7)
Not in label — unassessedserious n=30no trial data cached
Synovial cyst5210.5
8.0–13.8ROR 10.5 · calibrated p 0.030 ✓
10.0 EB05 7.8 · IC025 +2.8
3/3 methods agree
vs other Muscle Relaxants: PRR 5.6 (3.7–8.6)
Not in label — unassessedserious n=49 · ♀ 100% (drug 70%)no trial data cached
Intervertebral disc disorder4810.5
7.9–13.9ROR 10.5 · calibrated p 0.030 ✓
10.0 EB05 7.7 · IC025 +2.8
3/3 methods agree
vs other Muscle Relaxants: PRR 2.5 (1.7–3.6)
Not in label — unassessedserious n=45no trial data cached
Lumbar spinal stenosis3210.2
7.2–14.5ROR 10.3 · calibrated p 0.034 ✓
9.5 EB05 6.9 · IC025 +2.6
3/3 methods agree
vs other Muscle Relaxants: PRR 2.7 (1.7–4.3)
Not in label — unassessedserious n=30no trial data cached
Spinal operation13110.2
8.6–12.1ROR 10.2 · calibrated p 0.031 ✓
9.9 EB05 8.5 · IC025 +3.0
3/3 methods agree
vs other Muscle Relaxants: PRR 3.0 (2.4–3.7)
Reporting / coding artifactserious PRR 9.7no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

ReactionReportsPRR 95% CI · ROR · χ²/pEBGM EB05 · IC025Label screenSerious-only & strataTrial cross-check
Pain1,7312.6
2.5–2.7ROR 2.8 · calibrated p 0.712
2.6 EB05 2.5 · IC025 +1.3
3/3 methods agree
vs other Muscle Relaxants: PRR 2.4 (2.3–2.6)
Likely indication confounding
term in indications; also in warnings
serious PRR 2.7no trial data cached
Nausea1,6802.0
1.9–2.1ROR 2.1 · calibrated p 0.976
2.0 EB05 1.9 · IC025 +0.9
vs other Muscle Relaxants: PRR 2.7 (2.6–2.9)
Labeled adverse reaction
exact term
serious PRR 2.2no trial data cached
Fatigue (tiredness)1,6512.0
1.9–2.1ROR 2.1 · calibrated p 0.973
2.0 EB05 1.9 · IC025 +0.9
vs other Muscle Relaxants: PRR 3.0 (2.8–3.2)
Not in label — unassessedserious PRR 2.0no trial data cached
Drug ineffective (drug did not work)1,4981.1
1.0–1.1ROR 1.1 · calibrated p 0.347
1.1 EB05 1.0 · IC025 -0.0
PRR-only: not supported by EBGM or IC
vs other Muscle Relaxants: PRR 2.5 (2.3–2.6)
Reporting / coding artifactserious PRR 1.4no trial data cached
Headache1,2971.9
1.8–2.0ROR 2.0 · calibrated p 0.935
1.9 EB05 1.8 · IC025 +0.9
vs other Muscle Relaxants: PRR 2.6 (2.4–2.7)
Labeled adverse reaction
exact term
serious PRR 2.2no trial data cached
Diarrhoea (diarrhea)1,1841.7
1.6–1.8ROR 1.8 · calibrated p 0.800
1.7 EB05 1.6 · IC025 +0.7
vs other Muscle Relaxants: PRR 3.1 (2.8–3.3)
Not in label — unassessedserious PRR 1.7no trial data cached
Fall1,0963.1
2.9–3.3ROR 3.2 · calibrated p 0.572
3.1 EB05 2.9 · IC025 +1.5
3/3 methods agree
vs other Muscle Relaxants: PRR 2.5 (2.3–2.7)
Not in label — unassessedserious PRR 2.9no trial data cached
Dyspnoea (shortness of breath)1,0561.7
1.6–1.8ROR 1.8 · calibrated p 0.813
1.7 EB05 1.6 · IC025 +0.7
vs other Muscle Relaxants: PRR 2.8 (2.6–3.0)
Not in label — unassessedserious PRR 1.7no trial data cached
Arthralgia (joint pain)1,0362.3
2.2–2.5ROR 2.4 · calibrated p 0.861
2.3 EB05 2.2 · IC025 +1.1
3/3 methods agree
vs other Muscle Relaxants: PRR 3.0 (2.8–3.2)
Not in label — unassessedserious PRR 2.6no trial data cached
Off label use (used outside approved label)9801.0
1.0–1.1ROR 1.1 · calibrated p 0.341
1.0 EB05 1.0 · IC025 -0.0
PRR-only: not supported by EBGM or IC
vs other Muscle Relaxants: PRR 3.2 (2.9–3.4)
Reporting / coding artifactserious PRR 1.2no trial data cached
Dizziness9701.8
1.7–1.9ROR 1.8 · calibrated p 0.858
1.8 EB05 1.7 · IC025 +0.7
vs other Muscle Relaxants: PRR 2.8 (2.6–3.0)
Labeled adverse reaction
exact term
serious PRR 2.1no trial data cached
Back pain9293.7
3.5–4.0ROR 3.8 · calibrated p 0.409
3.7 EB05 3.5 · IC025 +1.8
3/3 methods agree
vs other Muscle Relaxants: PRR 2.8 (2.5–3.0)
Not in label — unassessedserious PRR 4.3no trial data cached
Anxiety9093.0
2.8–3.2ROR 3.0 · calibrated p 0.611
3.0 EB05 2.8 · IC025 +1.5
3/3 methods agree
vs other Muscle Relaxants: PRR 2.2 (2.1–2.4)
Not in label — unassessedserious PRR 3.2no trial data cached
Vomiting8571.7
1.6–1.8ROR 1.7 · calibrated p 0.786
1.7 EB05 1.6 · IC025 +0.7
vs other Muscle Relaxants: PRR 2.4 (2.2–2.6)
Labeled adverse reaction
exact term
serious PRR 1.7no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Methocarbamol?

In FDA FAERS, the most frequently co-reported reaction terms for Methocarbamol are pain, nausea, fatigue, headache, diarrhoea, fall. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Methocarbamol have an FDA boxed warning?

No. The FDA label retrieved for Methocarbamol has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Methocarbamol causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

Page generated 2026-10-14. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.