Introduction
Methadone, a synthetic opioid agonist, has been widely used for the
treatment of opioid dependence and chronic pain management for several
decades (1). Methadone maintenance treatment (MMT) has proven to be an
effective strategy in reducing illicit opioid use, improving patient
outcomes, and decreasing the risk of HIV transmission among individuals
with opioid use disorders (2). However, despite its therapeutic
benefits, methadone can cause significant adverse effects, particularly
in opioid-naive individuals or those who consume it recreationally (3).
Methadone overdose can lead to severe respiratory depression, cardiac
arrhythmias, and death (4). The risk of overdose is particularly high in
individuals who are not tolerant to opioids, as they may be more
sensitive to the drug’s effects (5). In addition to its well-known
respiratory and cardiovascular side effects, methadone can also cause
rare neurological and ocular manifestations, such as strabismus (6).
Strabismus, a misalignment of the eyes, can occur due to various
etiologies, including congenital factors, nerve palsies, and
pharmacological agents (7). Opioid-induced strabismus is an uncommon but
documented consequence of opioid toxicity, with most cases reported in
the context of heroin use (8). The exact mechanism underlying
opioid-induced strabismus remains unclear, but it is thought to involve
the drug’s effects on the central nervous system and the oculomotor
nerve (9).
In this case report, we present a rare instance of methadone-induced
loss of consciousness and subsequent strabismus in a patient who
consumed methadone for the first time. This case underscores the
importance of recognizing the potential dangers associated with
methadone use, especially in opioid-naive individuals, and the need for
healthcare providers to be aware of the uncommon ocular manifestations
of opioid toxicity. Prompt identification and appropriate management of
methadone overdose and its associated complications can prevent
long-term morbidity and mortality (10).