Current status of pheniramine misuse among substance use disorder patients: A narrative review of extent, patterns, and clinical implications.

BackgroundThere is growing concern about the misuse of Over-the-counter (OTC) medications around the world. Pheniramine is a first-generation antihistamine, which is widely available and is commonly used for allergic conditions. Initially considered to be a safe anti-allergic agent, growing evidence suggests its potential for misuse and dependence. Notably, it is reported that pheniramine is being used to mix other substances such as opioids during injection drug use. However, pheniramine misuse is not adequately studied in existing literature.ObjectiveThis review aims to synthesize the literature on pheniramine misuse, and summarize the published case reports on pheniramine misuse to understand its clinical implications.MethodsA comprehensive literature search was conducted using PubMed, Google Scholar, and MedSearch to identify case reports, epidemiological data, and clinical studies regarding pheniramine misuse. We included articles in English language, published in peer- review journals, and indexed in PubMed. The keywords for the search included 'Pheniramine use', 'misuse' 'abuse', 'dependence', 'harmful use', 'substance use disorder', 'opioid use disorder', and 'injecting drug user'.ResultsPheniramine has misuse potential comparable to Lorazepam. It is often combined with opioids and/or diazepam and used through injection route, commonly in South Asian region. Studies on extent of its use are mainly from South Asia, which report comorbid use of pheniramine ranging from around 15% to 80% in injection drug users. Use of pheniramine is often under-reported by patients. In literature, more than 8 case reports describe the misuse/dependence of pheniramine and associated complications such as seizures, psychosis, and life-threatening toxicity. Easy accessibility might be one of the contributing factors for pheniramine misuse.ConclusionPheniramine misuse is an emerging challenge and clinicians should remain vigilant about its signs, especially in those with substance use and psychiatric comorbidities.