Baclofen is a GABAb receptor agonist with powerful antinociceptive effects in experimental animal models and established efficacy for chronic pain. It may be most useful in blocking the lancinating or episodic types of pain and reducing allodynia. It is commonly used for trigeminal neuralgia together with carbamazepine. Baclofen may be started in doses of 5 mg two to three times per day and may be escalated to a maximum dose of 200 mg given in divided doses.
Common side effects include central nervous system symptoms, such as dizziness and drowsiness, as well as gastrointestinal symptoms. Baclofen is a highly hydrophilic agent and has poor penetration of the blood-brain barrier. Intrathecal baclofen could be a promising adjuvant therapy to enhance the effect of other intrathecal medications such as morphine or clonidine, or spinal cord stimulation for chronic pain.