Behavioral abnormalities in older patients with chronic renal function decline following administration of compound paracetamol and amantadine hydrochloride capsules.

BACKGROUND

Compound paracetamol and amantadine hydrochloride capsules are commonly used over-the-counter medications at the primary care level. The primary component, amantadine, is excreted via the kidneys and poses a risk of accumulation in older patients, while chlorphenamine may increase the risk of delirium. This study examines the relationship between this medication and abnormal behavior by presenting case studies of two older patients and discussing clinical management strategies.

CASE PRESENTATION: Case 1 involved a 78-year-old Chinese male with an estimated glomerular filtration rate (eGFR) of 87 mL/min/1.73 m2, who developed visual hallucinations, delirium, and balance disturbances after five consecutive days of medication. He scored 8 on the Nursing Delirium Screening Scale. Symptoms resolved within 8 days following hydration therapy and antipsychotic treatment. Case 2 featured a 75-year-old Chinese male with an estimated glomerular filtration rate of 37 mL/min/1.73 m2, who exhibited disorientation and hallucinations within 24 hours of starting the medication, scoring 10 on the Nursing Delirium Screening Scale. His symptoms completely resolved in 3 days. Both cases excluded alternative etiologies, and Naranjo Adverse Drug Reaction Probability Scale scores of 7 indicated a "probable" association between the drug and the behavioral abnormalities. Pharmacokinetic analysis revealed a strong correlation between drug accumulation, renal function status, and treatment duration.

CONCLUSION

The central toxicity of amantadine is significantly enhanced in older patients with renal insufficiency, and chlorphenamine may increase the risk of delirium. The risks associated with using this medication in older patients suffering from the common cold far outweigh the benefits, warranting cautious use in clinical practice; adverse reactions should be managed with prompt discontinuation of the medication and hydration to facilitate drug clearance. This study provides crucial warnings about medication safety in the older population.