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.