baklō–/fen

Brand Names: Lioresal®

  • Generic Available

Common Dosage Forms:

  • Tablets: 10 mg and 20 mg
  • Injection: Available in 50 mcg/mL, 500 mcg/mL, 1,000 mcg/mL, and 2,000 mcg/mL (Gablofen®)

FDA Indications/Dosages:

  • For the signs and symptoms of spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity: Titration to the optimum dose is recommended. Start with 5 mg orally given three times a day. Dosage increases of 5 mg per dose can be made every 3 days up to a maximum of 80 mg per day (20 mg given four times a day). Normal dosage range is 10 to 20 mg given three to four times a day.

Pharmacology/Pharmacokinetics:

Baclofen is an analog of gamma-aminobutyric acid (GABA). It most likely works at the spinal cord level, reducing both the flexor and extensor spasms. Its mechanism of action may be due to a hyperpolarization of afferent terminals resulting in inhibition of monosynaptic and polysynaptic reflexes. Peak plasma levels are reached about 1 to 2 hours following an oral dose. The majority of the dose is excreted in the urine as unchanged drug. The elimination half-life of baclofen is approximately 6 hours.

Drug Interactions:

CNS depression is increased when used with other CNS depressants.

Contraindications/Precautions:

Contraindicated in patients hypersensitive to baclofen. Use with caution in patients with impaired renal function, epilepsy, or those with a history of stroke. Do not discontinue abruptly due to a risk of hallucinations and seizures. Phenylketonurics should be warned that orally-disintegrating tablets contain phenylalanine. Use with caution in nursing mothers. Pregnancy Category C.

Adverse Effects:

The most common adverse effect is drowsiness. Other common effects include dizziness, weakness, fatigue, confusion, headache, insomnia, nausea, constipation, and urinary frequency.

Patient Consultation:

  • May cause drowsiness. Use caution while operating machinery or when mental alertness is required.
  • Avoid alcohol while taking this medication.
  • Store in a cool, dry place away from sunlight and children.
  • Contact a physician if the above side effects are severe or persistent.
  • If a dose is missed, skip it and return to normal dosing schedule.