Abstract Details

Title Neurotoxicity of Topical Medications

Topic Clinical Neurophysiology

Presentation(s) P01 - (-)

Poster/Presentation
Number 040

Objective

Background Consistent documentation of topical medications during a physician visit is rare. Their omission may lead to delayed identification of potential side effects caused by their routine, prolonged or inappropriate use that could be clinically relevant.

Design/Methods We conducted a review of published articles in Pubmed and Medline using the search words 'topical drug toxicity,' 'neurotoxicity,' 'peripheral neuropathy,' and 'CNS drug toxicity.'

Results We identified seven drugs with either central or peripheral neurotoxicity from topical use including lindane, retinoic acid, benzalkonium chloride, hexachlorophene, clioquinol, metronidazole and topical mercury compounds. We outlined their commercial availability, current indications, and their clinical toxicity profile. While clinical toxicity is sparsely reported, it is particularly striking in severity considering their use for relatively benign indications. Most are used as topical antiseptics, surgical scrubs, and over the counter coloring compounds. From milder side effects of occasional headaches and muscle spasms to disconcerting findings of irreversible blindness, seizures, and sensorimotor neuropathy, these drugs as a group deserve mention especially in light of their poorly documented and monitored use. Pertinent to this topic is the current use in clinical trials of enteric preparations of clioquinol in the treatment of neurodegenerative disorders and hematological malignancies. Clioquinol is a zinc and copper chelator. Both of these metals are implicated in the stabilization of amyloid plaques; hence its potential use in plaque dissolution. However case reports and in-vitro studies have implicated clioquinol-zinc chelate as a candidate agent responsible for subacute myelo-optic neuropathy questioning its safety.

Conclusions Topical medications are often dismissed as benign, assuming minimal absorption and limited systemic effects, and may be omitted from most medical documentation. Physicians should remain aware of their potential neurotoxicity and consider discontinuation if warranted.

Authors/Disclosures
Jhanvi Menon, MD (Kaiser Permanente) PRESENTER	No disclosure on file
Boyd M. Koffman, MD, PhD (University of Toledo Department of Neurology)	Dr. Koffman has nothing to disclose.
Rana Karabudak, MD (Academic Neurologist)	Dr. Karabudak has nothing to disclose.

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