THERAPEUTICS

Brands

• Soma, Sanoma, Carisoma, Rela

Generic?

• Yes

Class

• Muscle relaxant

Commonly Prescribed for

(FDA approved in bold)

• Acute painful musculoskeletal conditions

• Muscle spasm

• Insomnia

How the Drug Works

• Sedative. Both carisoprodol and its active metabolite (meprobamate) bind to GABAA and may block interneuronal activity, depressing transmission of polysynaptic neurons in the descending reticular formation (sedation) and spinal cord (decreasing pain)

How Long Until It Works

• Pain: as little as 30 minutes and typically lasts 2–6 hours

If It Works

• Titrate to most effective tolerated dose

If It Doesn't Work

• Increase dose. If ineffective, consider alternative medications

Best Augmenting Combos for Partial Response or Treatment-Resistance

• Analgesic pain management often used in combination

• Botulinum toxin is effective, especially as an adjunct for focal spasticity (e.g., post-stroke or head injury affecting the upper limbs)

• Use other centrally acting muscle relaxants with caution due to potential additive CNS depressant effect

Tests

• None required

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Most are related to sedative effects

Notable AEs

• Drowsiness, dizziness, vertigo, ataxia, depression, nausea/vomiting, tachycardia, postural hypotension, facial flushing

Life-Threatening or Dangerous AEs

• Hypersensitivity reactions rarely occur after the first dose. Symptoms include extreme weakness, ataxia, vision loss, dysarthria, and euphoria. Serious allergic reactions, such as erythema multiforme, eosinophilia, asthmatic episodes, fever, angioedema, and anaphylactoid shock have been reported

Weight Gain

• Unusual

Sedation

• Common

What to Do About AEs

• Reduce dosing frequency for mild AEs and discontinue for serious AEs

Best Augmenting Agents to Reduce AEs

• Most AEs cannot be reduced by an augmenting agent

DOSING AND USE

Usual Dosage Range

• 1 tablet 3–4 times daily

Dosage Forms

• Tablets: 250, 350 mg

How to Dose

• Give 1 tablet 3 times a day and at bedtime