Drug deafness is a common type of sensorineural deafness. Generally speaking, the causes of drug deafness are mainly the following: 1. Genetic susceptibility This genetic susceptibility is characterized by matrilineal inheritance, such as aminoglycoside antibiotics. A large number of studies have confirmed that mitochondrial mutations are closely related to deafness, and the mitochondrial DNA mutations that have a clear pathogenic mechanism and are closely related to the development of drug deafness are A1555G and C1494T. Both mutations can cause structural changes in mitochondrial 12SrRNA so that aminoglycoside antibiotics can bind more closely to them and cause damage to inner ear hair cells. The mitochondrial inheritance has maternal genetic characteristics, and individuals with this mutation are highly sensitive to aminoglycoside antibiotics, leading to the common clinical phenomenon of “one shot deafness”. The dose and time of medication include the total amount of medication and daily dose. The larger the daily dose, the longer the dosing time, the more chances of poisoning. The daily dose is more likely to cause poisoning than the one-time dose. If two or more ototoxic drugs are used in combination, there is a high chance of poisoning. For example, gentamicin and tachyphylaxis, gentamicin and erythromycin are used in combination. 4. Route of administration Intrathecal administration is the most dangerous, followed by intravenous and intramuscular injection. The absorption rate of oral aminoglycoside antibiotics is low under normal circumstances, but when inflammatory lesions occur in the intestinal mucosa, especially hemorrhagic and necrotizing enteritis, the absorption of drugs increases and can damage the hair cells of the inner ear; large burns, pleurisy, and intrabronchial drug delivery, drugs can be absorbed locally and poisoning occurs; when local drops are administered in otitis media, drugs can also enter the inner ear through the round window membrane and through the middle ear vessels. In addition, the ototoxicity of drugs can be increased when there is inflammation in the middle ear. 5, through the placenta Aminoglycoside antibiotics can also enter the fetal blood circulation through the placenta, although the concentration of drugs in the fetal serum is only 15%-50% of the concentration in the maternal serum, but because the drug excretion rate in the fetus is very slow, so it can damage the fetal hearing. Especially in the first three months of pregnancy, the early stages of pregnancy is more obvious. Age and body condition Data show that infants, pregnant women and the elderly are prone to drug toxicity deafness; most ototoxic drugs are excreted by the kidneys, poor kidney function or damage to kidney function during the use of drugs, the excretion of drugs is impaired and can cause ototoxic effects due to accumulation. 7. Noise, vibration, starvation state, diabetes, etc. can promote or aggravate ototoxicity.