Schedule H

Oral, Intramuscular

• Tablets: 4 mg, 8 mg

• Capsules: 8 mg

• Injectable: 2 mg/mL (4 mL ampoule = 8 mg) — IM use only

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Acute Muscular Spasm (low back pain, cervical spondylosis, post-traumatic spasm)

Typically used as adjunct to NSAIDs for short-term management only

Oral Route:

Parameter Recommendation

Starting dose 4 mg twice daily

Titration May increase to 8 mg twice daily if inadequate response

Usual maintenance dose 8 mg twice daily

Maximum dose 16 mg/day

Maximum duration 7 consecutive days (strict limit)

Clinical notes Administer after meals; use only as adjunct therapy; reassess if no improvement in 3–5 days

Intramuscular Route:

Parameter Recommendation

Starting dose 4 mg once daily

Titration May increase to 4 mg twice daily if needed

Usual maintenance dose 4–8 mg/day in 1–2 divided doses

Maximum dose 8 mg/day (maximum 2 injections/day)

Maximum duration 5 consecutive days (strict limit)

Route restriction IM ONLY — IV administration is contraindicated

Clinical notes Deep IM injection into gluteal muscle; rotate injection sites

Secondary Indications – Adults Only (Off-label, if any)

Not applicable — No well-documented off-label indications in Indian clinical practice.

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India)

Not approved for paediatric use in India.

• Contraindicated in children and adolescents below 16 years of age

• Safety concerns include seizure risk and potential genotoxicity

Secondary Indications – Paediatric Doses (Off-label, if any)

Not applicable — Off-label paediatric use is not recommended due to safety concerns.

Clear Statement:

Thiocolchicoside should NOT be used in patients below 16 years of age under any circumstances, including off-label use. This restriction is based on CDSCO advisories and international safety communications regarding seizure risk and genotoxicity concerns.

Mild to moderate impairment No dose adjustment required

• Known hypersensitivity to thiocolchicoside or any excipient

• History of epilepsy or seizure disorders

• Active seizures or conditions predisposing to seizures

• Children and adolescents below 16 years of age

• Pregnancy (all trimesters)

• Lactation

• Intravenous administration (serious safety risk — IM only)

• Flaccid paralysis or hypotonia syndromes

• Concurrent use with other drugs that lower seizure threshold (in patients at risk)

• Duration of therapy must not exceed 7 days (oral) or 5 days (IM) — genotoxicity risk with prolonged exposure

• History of febrile convulsions in childhood

• Concurrent CNS depressants (opioids, benzodiazepines, alcohol)

• Hepatic impairment — hepatotoxicity has been reported

• Elderly patients — increased CNS sensitivity

• Concurrent use with drugs lowering seizure threshold

• Driving or operating machinery — may cause somnolence and dizziness

• Women of childbearing potential not using effective contraception

Parameter Details

Overall Safety Contraindicated throughout pregnancy

Risk Category Not recommended — teratogenic and embryotoxic in animal studies

Human Data Insufficient; presumed high risk based on mechanism and animal data

Preferred Alternatives Paracetamol for analgesia; physiotherapy for muscle spasm

If Inadvertent Exposure Discontinue immediately; specialist obstetric consultation; fetal monitoring

Contraception Advice Women of childbearing potential should use effective contraception during treatment

Parameter Details

Compatibility Contraindicated during breastfeeding

Excretion in Milk Not well quantified; potential genotoxic risk to infant

Preferred Alternatives Paracetamol, ibuprofen (short-term); non-pharmacological measures

If Use Unavoidable Discontinue breastfeeding during treatment and for 24 hours after last dose

Infant Monitoring Not applicable — breastfeeding should be avoided

Parameter Recommendation

Starting dose 4 mg twice daily (conservative initiation)

Titration Slow; increase to 8 mg twice daily only if clearly needed and tolerated

Maximum dose 16 mg/day (use lowest effective dose)

Special Risks Increased CNS sensitivity — higher risk of sedation, dizziness, falls, cognitive impairment

Additional Concerns Polypharmacy interactions common; assess for concurrent CNS depressants

Monitoring Close observation for somnolence, confusion, gait disturbance; limit duration strictly

Interacting Drug Effect / Mechanism Management

Opioids (tramadol, morphine, codeine) Additive CNS depression; excessive sedation; respiratory depression risk Avoid combination if possible; if essential, use lowest doses and monitor closely

Benzodiazepines Enhanced sedation; increased fall risk Avoid concurrent use; if necessary, reduce doses of both

Alcohol Potentiated CNS depression; impaired psychomotor function Counsel strict alcohol avoidance during treatment

Antiepileptics (at sub-therapeutic levels) May lower seizure threshold; breakthrough seizures possible Ensure adequate seizure control before initiating; monitor closely

Drugs lowering seizure threshold (tramadol, antipsychotics, TCAs) Increased seizure risk Avoid combination in at-risk patients

Interacting Drug Effect / Mechanism Management

NSAIDs (diclofenac, aceclofenac) Commonly co-prescribed; additive GI irritation Monitor for GI symptoms; consider PPI cover

Antihypertensives with sedative properties (clonidine, methyldopa) Enhanced hypotension and sedation Monitor blood pressure and CNS symptoms

Anticholinergics Enhanced sedation; confusion risk especially in elderly Use with caution; monitor for CNS effects

Antihistamines (sedating) Additive sedation Avoid concurrent use or use non-sedating alternatives

Oral contraceptives Theoretical concern regarding GABA-mediated effects on ovulation Use with caution; advise additional contraceptive measures if concerned

• Somnolence, drowsiness

• Dizziness, lightheadedness

• Nausea, vomiting

• Diarrhoea

• Gastric discomfort, dyspepsia

• Fatigue, asthenia

• Headache

• Injection site pain (IM route)

Adverse Effect Notes

Seizures Especially at high doses or in patients with predisposing factors; requires immediate discontinuation

Hepatotoxicity Elevated transaminases, hepatitis (rare); discontinue if LFTs significantly elevated

Genotoxicity Risk with prolonged or high-dose exposure — strict adherence to duration limits essential

Severe hypersensitivity reactions Anaphylaxis, angioedema; immediate discontinuation and emergency management

Vasovagal syncope Reported with IM injection; administer in supine position

Rhabdomyolysis Rare; monitor for muscle pain, weakness, dark urine

→ Immediate discontinuation mandatory if seizures, hepatotoxicity, or severe hypersensitivity occur.

During treatment CNS symptoms (sedation, dizziness, confusion); GI tolerance; any seizure activity

If treatment extended beyond 5 days LFTs (though extension beyond recommended duration is discouraged)

Post-treatment Ensure resolution of muscle spasm; assess need for continued therapy (should be discontinued)

Single-ingredient formulations:

• Myoril (Sanofi)

• Muscoril (Sanofi)

• Thiocolcid (Micro Labs)

• Myospaz (Alkem)

Common Fixed-Dose Combinations (FDCs):

Note: FDCs are widely prescribed but increase polypharmacy risk and require attention to GI safety and duration limits.

• NLEM Status: Not included in NLEM 2022

• Government supply: Not available in public health facilities

1. Strict duration limits are non-negotiable: Maximum 7 days oral, 5 days IM — prolonged use carries genotoxicity risk that has prompted international safety alerts.

1. Avoid in seizure-prone patients: Thiocolchicoside lowers seizure threshold — contraindicated in epilepsy; use caution with concurrent drugs that also lower seizure threshold (tramadol, antipsychotics).

1. IM route is exclusively intramuscular: Never administer intravenously — serious adverse reactions reported with IV use.

1. Not a long-term muscle relaxant: For chronic spasticity (e.g., in spinal cord injury, multiple sclerosis), use baclofen or tizanidine instead.

1. Counsel on sedation: Advise patients to avoid driving and operating machinery; synergistic sedation with alcohol and CNS depressants.

1. Absolutely contraindicated in pregnancy and lactation: Ensure pregnancy status before prescribing to women of childbearing potential; advise effective contraception.

thiocolchicoside; muscle relaxant; back pain; cervical spondylosis; acute spasm; genotoxicity; seizure-risk; pregnancy-contraindicated; lactation-contraindicated; short-term-use; Schedule-H; IM-only

RxIndia v1.0 — 10 Jan 2025

• CDSCO approved product information and safety advisories

• Indian Pharmacopoeia / National Formulary of India 2021

• AIIMS Drug Formulary

• ICMR Clinical Safety Communications

• API Textbook of Medicine

• European Medicines Agency Safety Communication (for genotoxicity risk context — supportive reference)

• Indian orthopaedic and rheumatology clinical practice