[Drug Interactions in Neurology and Psychiatry].

Among drug-drug interactions, pharmacokinetic drug interactions are those in which multiple drugs interact to produce fluctuations in their blood concentrations, and mainly involve drug-metabolizing enzymes (cytochrome P450, UDP-glucuronyltransferase) and drug transporters (P-glycoprotein, etc.). The risk of drug interactions along with an increase in the number of drugs being used simultaneously; therefore, it is important to know the mechanisms of drug interactions, and the drugs to be wary of, as well as to make efforts to reduce the number of drugs used as much as possible.

A case of musical hallucinations induced by tramadol.

AIM: Although tramadol has been suggested to have a higher risk of producing hallucinations than other opioids, reports of musical hallucinations are extremely rare. CASE PRESENTATION: A 72-year-old woman came to our department complaining of auditory hallucinations. She had been diagnosed with lumbar spinal canal stenosis associated with herniated and slipped disks. Due to persistent back pain, tramadol was started, and the dose was increased to 300 mg/day. The next day, she began to hear nursery rhymes, songs of the Ministry of Education, and folk songs. The musical auditory hallucinations disappeared with the use of antipsychotics and the discontinuation of tramadol. No relapse of musical auditory hallucinations was observed after the discontinuation of antipsychotics. CONCLUSION: Based on the clinical course, we concluded that the auditory hallucinations were musical hallucinations induced by tramadol.

Laryngeal schwannoma with extralaryngeal extension mimicking a thyroid tumour.

Objective: A schwannoma is a common benign tumour that can arise anywhere in the body. When it occurs in an unusual location such as the larynx, its differentiation from other tumours can be challenging. Herein, we report a case of a laryngeal schwannoma with extralaryngeal extension that mimicked a thyroid tumour, focusing on its characteristic features on MRI. Methods: A 19-year-old male presented with a mass in the left side of the neck and hoarseness for 2 years. Endoscopy showed a submucosal mass in the laryngeal region. MRI found a well-defined solid mass in the thyroid gland, extending to the larynx through the lower edge of the thyroid cartilage. T 2 weighted MRI showed slightly low signal intensity at the central part of the tumour and high signal intensity at the peripheral part of the tumour. Pre-operative imaging suggested that the tumour originated in the thyroid gland. Left thyroidectomy with tumour excision was performed; the tumour was diagnosed as a laryngeal schwannoma with extralaryngeal extension, compressing the thyroid gland. In retrospect, features such as the dumbbell-shape and known as 'target sign' on T 2 weighted MRI were typical features of schwannoma. Additionally, the tumour's extension pattern was similar to previous reports of laryngeal schwannomas with extralaryngeal extension. Conclusion: A large laryngeal schwannoma may extend outside the larynx with significant compression of the thyroid gland. Understanding the pattern of extension and familiarity with the features on MRI can improve the preoperative diagnosis accuracy.