According to the Japan Poison Information Center (JPIC), topical skin medications represent the most common accidentally ingested over-the-counter (OTC) drugs among those aged ≥65 years. Specifically, the unintentional consumption of readily available multi-ingredient antipruritic topical agents is reportedly associated with severe reactions.

Based on a dataset from JPIC, which spans 34 years and comprises inquiries from medical establishments with verifiable outcomes, we investigated patients aged ≥60 years with a history of multi-ingredient antipruritic medication ingestion and need for subsequent hospital care. Of 18 verified cases in which patients consumed OTC topical agents containing at least two of the following products : camphor, local anesthetics, and antihistamines, 14 patients required inpatient treatment. All incidents were attributable to cognitive decline, and most such accidents occurred within residential settings or elderly care facilities. Impaired consciousness was observed in ＞90％ of these patients ; the Glasgow Coma Scale score was ≤8 in eight patients. Notably, one patient experienced pre-hospital cardiopulmonary arrest, one patient developed respiratory arrest, and two had convulsions ; overall, nine patients required respiratory support. Compared with single-agent products, combination drugs demonstrated a higher potential for severe outcomes, even when ingested in small quantities. Our findings underscore the urgent need for preventive strategies against the accidental consumption of OTC antipruritic topical agents among elderly patients, to avoid the potentially life-threatening risks associated with such unintentional ingestion.

Methylene blue has been used globally outside of Japan as a treatment for methemoglobinemia. In Japan, it was specified as a highly necessary drug by the Ministry of Health, Labour and Welfare’s Review Committee on Unapproved and Off-label Drugs with High Medical Needs. Methylene blue intravenous injection 50 mg “Daiichi Sankyo” (MB) was approved in Japan in December 2014. As a condition of approval, post-marketing surveillance was required for all patients with methemoglobinemia who received MB in Japan. The safety and effectiveness of MB based on the post-marketing surveillance data are reported. Of the 46 patients in the safety analysis set, 5 developed adverse drug reactions with a causal relationship to MB, of which 3 were serious hemolytic anemia, which has already been mentioned in the Japanese package insert. In the 41 patients in the effectiveness analysis set, the blood methemoglobin (MetHb) level decreased significantly from pre-treatment (32.4％) to post-treatment (2.0％). MetHb levels decreased by half in 38 patients with a median half-life of 2.7 hours, showing a rapid reduction after starting MB treatment. Regarding the prognosis after MB treatment, 36 patients were recovered, 0 had sequelae, and 5 died. No causal relationship of MB to death was observed in the 5 patients who died. In this all-patient, post-marketing surveillance, MB showed safety and effectiveness in patients with methemoglobinemia in Japan.

A 55-year-old woman attempted suicide by overdosing on precipitation drugs (such as valproic acid (VPA) and phenobarbital). She was intubated in the emergency room due to a low level of consciousness, unstable respiratory and circulatory status, and evidence of pneumonia on a CT scan. Her serum VPA concentrations were high (＞150 μg/dL), indicating severe VPA intoxication. After hemodialysis therapy, repeated meropenem (MEPM) administration, and multidisciplinary treatment, her serum VPA concentrations rapidly declined and her general condition improved. She was successfully extubated on day 13 and transferred to another hospital on day 26 without any aftereffects.

VPA is commonly prescribed for conditions such as epilepsy, migraines, and depression. Large doses of VPA can cause fatal cerebral edema and death;therefore, reducing serum VPA concentrations as soon as possible is critical to the management of severe VPA intoxication. The liver metabolizes VPA, which then enters enterohepatic circulation. Acylpeptide hydrolase (APEH) removes the glucuronic acid group from VPA, thereby allowing its reabsorption in the gastrointestinal tract. Administration of MEPM can irreversibly inhibit the activity of APEH and prevent VPA reabsorption. Although it is counterintuitive, we suggest using MEPM along with VPA as a potential treatment for severe VPA intoxication.

Borax is a borate compound used as a cleaning agent and as fertilizer, and its use as a material for homemade ‘slime’ has been increasing in recent years. There are few reports of acute borax poisoning. We describe a case of acute poisoning in which approx. 11 g of borax was ingested by a woman in her teens. We attempted to quantify the amount of borax ingested by performing a colorimetric analysis, which has been used to quantify boric acid. The colorimetric analysis of boric acid was conducted using a spectrophotometric determination of boric acid by the curcumin method, and serum samples were used for this measurement at approx. 4 h after the ingestion of borax. The results revealed a serum concentration of boric acid at 68.28 μg/mL (1.104 mmol/L). The borax concentration calculated using this boric acid concentration was 105.3 μg/mL. These results demonstrate that the spectrophotometric determination of boric acid by the curcumin method can be applied in cases of acute borax poisoning.