Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory,
antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of
respiratory tract diseases and has shown to be efficacious in relieving
sore throat. In more recent years,
ambroxol has gained interest for its potential usefulness in treating
neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary
analgesic mechanism of action-blockade of voltage-gated
sodium (Na v ) channels in sensory neurons.
Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of
neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of
chronic pain. In this review, we discuss the
analgesic mechanisms of action of
ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent
pain and
neuropathic pain symptoms, including
trigeminal neuralgia,
fibromyalgia, and
complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness,
ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for
neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for
neuropathic pain to market.