Ibudilast: a non‑selective phosphodiesterase inhibitor in brain disorders

Ibudilast (IBD) is a non‑selective (3, 4, 10, 11) phosphodiesterase (PDE) inhibitor, used mainly as a bronchodilator for the treatment of bronchial asthma. PDE play a central role in cellular function (e.g. differentiation, synaptic plasticity and inflammatory response) by metabolizing cyclic nucleotides. The results from preclinical and clinical studies indicate that IBD has a broader range of action through suppression of pro‑inflammatory cytokines (IL‑6, IL‑1β, TNF‑α), toll‑like receptor 4 blockade (TLR‑4), inhibition of a macrophage migration inhibitory factor (MIF), up‑regulation the anti‑inflammatory cytokine (IL‑10), and promotion of neurotrophic factors (GDNF, NGF, NT‑4). Recent data indicate that the efficacy of IBD appears to be independent from PDE inhibition activity and rather linked to glial activity attenuation. Additional advantages of IBD, such as crossing the blood-brain barrier, good tolerance and activity by oral administration, makes it a promising therapeutic candidate for treating neuroinflammatory conditions, where the currently available treatment remains unsatisfying due to poor tolerability and/or sub‑optimal efficacy. IBD has no direct receptor affinity with exemption of some undefined effect on adenosine receptors that makes the drug devoid of its receptors‑mediated adverse effects. Current article provides an overview of the pharmacology of IBD with a focus on preclinical and clinical data supporting its potential neuroprotective benefits for neurological conditions, including multiple sclerosis, neuropathic pain, medication overuse headache, stroke, opioid, alcohol and methamphetamine abuse.