Overview
DESCRIPTION Baclofen, USP is a muscle relaxant and antispastic. Its chemical name is 4-amino-3-(4-chlorophenyl)-butanoic acid. The structural formula is: C 10 H 12 ClNO 2 M.W. 213.66 Baclofen, USP is a white to off-white odorless or practically odorless crystalline powder. It is slightly soluble in water, very slightly soluble in methanol and insoluble in chloroform.
Mechanism of Action
CLINICAL PHARMACOLOGY The precise mechanism of action of baclofen is not fully known. Baclofen is capable of inhibiting both monosynaptic and polysynaptic reflexes at the spinal level, possibly by hyperpolarization of afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect. Although baclofen is an analog of the putative inhibitory neurotransmitter gamma-aminobutyric acid (GABA), there is no conclusive evidence that actions on GABA systems are involved in the production of its clinical effects. In studies with animals baclofen has been shown to have general CNS depressant properties as indicated by the production of sedation with tolerance, somnolence, ataxia, and respiratory and cardiovascular depression.
Indications
- INDICATIONS AND USAGE Baclofen tablets, USP are useful for the alleviation of signs and symptoms of spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity. Patients should have reversible spasticity so that baclofen treatment will aid in restoring residual function. Baclofen tablets, USP may also be of some value in patients with spinal cord injuries and other spinal cord diseases. Baclofen tablets, USP are not indicated in the treatment of skeletal muscle spasm resulting from rheumatic disorders.
Common Doses
- 80 mg
- 5 mg
- 10 mg
- 15 mg
Dosage
DOSAGE AND ADMINISTRATION The determination of optimal dosage requires individual titration. Start therapy at a low dosage and increase gradually until optimum effect is achieved (usually between 40-80 mg daily). The following dosage titration schedule is suggested: 5 mg t.i.d. for 3 days 10 mg t.i.d. for 3 days 15 mg t.i.d. for 3 days 20 mg t.i.d. for 3 days Thereafter additional increases may be necessary but the total daily dose should not exceed a maximum of 80 mg daily (20 mg q.i.d.). The lowest dose compatible with an optimal response is recommended.
Contraindications
- CONTRAINDICATIONS Hypersensitivity to baclofen.
Side Effects
- ADVERSE REACTIONS The most common is transient drowsiness (10 to 63%). In one controlled study of 175 patients, transient drowsiness was observed in 63% of those receiving baclofen compared to 36% of those in the placebo group. Other common adverse reactions are dizziness (5 to 15%), weakness (5 to 15%) and fatigue (2 to 4%). Others reported: Neuropsychiatric: Confusion (1 to 11%), headache (4 to 8%), insomnia (2 to 7%); and, rarely, euphoria, excitement, depression, hallucinations, paresthesia, muscle pain, tinnitus, slurred speech, coordination disorder, tremor, rigidity, dystonia, ataxia,...
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.