BACLOFEN

Day 1: As it is chemically related to the neurotransmitter GABA, #baclofen was trialed for epilepsy in the 1960s, but found ineffective, However, a centrally acting muscle relaxant effect was discovered & it was licensed for this in the 1970s

Day 2: #baclofen is licensed from 1 month old for relief/pain of muscle spasm for spasticity, palliative care & gastric distension hiccup in palliative care. Adult oral dose muscle spasm range 5-20mg up to three times daily. Intrathecal use for severe unresponsive spasticity. In the UK #baclofen is used first-line for muscle spasticity linked to multiple sclerosis

Day 3: Good oral bioavailability & fast onset of action at around 1hr. Poor lipid solubility means poor blood/brain barrier penetration, so high doses are needed. #baclofen undergoes minimal metabolism/can be used in liver impairment. T½ 2-6 hrs. As water soluble, excreted renally ‘unchanged’. Dose adjustment if renal impairment

Day 4: As a GABAb agonist, #baclofen acts centrally to inhibit spinal cord signal transmission, inhibit reflexes & reduce spasticity. Activating the GABAb receptor leads to neuronal hyperpolarisation & lower action potentials. Tolerance to #baclofen, especially with intrathecal use is reported; may require a ‘drug holiday’