Spectrum of toxicity due to pheniramine overuse in a COVID-19 patient. How much do we know?

Pheniramine maleate is an easily accessible, potent antihistaminic compound used for the treatment of various allergic conditions. It acts on histamine one (H1) receptors on the central nervous system (CNS) and the peripheral tissues. It is a safe drug in therapeutic doses. However, overdoses as in suicidal cases, can result in serious, life-threatening drug-toxicity. These include atropine-like antimuscarinic effects like dryness of mucosal membranes, blurring of vision, hallucinations, CNS excitation such as irritability, insomnia, and seizures. Rhabdomyolysis can also occur as a result of its direct toxic effect on muscles, resulting in myoglobinuria, renal failure and electrolyte imbalance. Cardiotoxicity though rare, is also reported. We report a case of pheniramine maleate induced ventricular tachycardia, myoglobinuria with acute kidney injury (AKI) in a 20-year-old man who had consumed 50 tablets. He was incidentally also found to have SARS-CoV2 infection. However, timely intervention and aggressive supportive therapy helped in the recovery of the patient.