Aminoglycosides are potent, broad-spectrum class antibiotics which act by inhibition of bacterial protein synthesis. These are traditional antibacterial medications for gram-negative bacterial infections.
Antibacterial medicines coming under this class of ‘aminoglycosides’ are gentamicin, amikacin, tobramycin, and neomycin.
Medicines and Healthcare products Regulatory Agency (MHRA) – United Kingdom regulatory health authority released a drug safety update of increased risk of ototoxicity (toxic effects to ear) with aminoglycoside class of medicines.
Known adverse reaction: A reminder for increased risk
Aminoglycoside class of medicines have narrow therapeutic window and can cause nephrotoxicity and ototoxicity (can result in permanent hearing loss). Occurrence and severity of toxic effects are dose-dependent and duration of treatment and could exacerbate in special group of populations (paediatric, geriatric, hepatic and renal impairment patients).
Based on the evidence of published epidemiological studies, increased risk of ototoxicity (deafness) was identified in patients with mitochondrial mutation m.1555A>G even though patient’s serum aminoglycoside levels are within the recommended limits. Some case reports presented deafness in patients having a maternal history of deafness or mitochondrial mutations or both.
The m.1555A>G mutation is the most common mitochondrial DNA (mtDNA) mutation, with an estimated prevalence of 0.2% in the general population which is associated with sensorineural deafness and occurs in families with maternally transmitted deafness.
Regular monitoring of aminoglycoside levels in serum concentration is recommended to maintain drug levels below the toxic threshold for the cochleo-vestibular system, which can minimize the risk of ototoxicity associated with systemic aminoglycosides
The product information for each medicine provides dosing considerations and recommendations for toxicity thresholds.
Assessment of auditory, vestibular, and renal function is particularly necessary in patients with additional risk factors.
10 case reports pertaining to this safety concern suggested a plausible biological mechanism for ototoxicity associated with aminoglycoside use (systemic & local application at the site of toxicity – ear).
Every medicinal product has both benefits and risks. Medicines are authorized to market based on the favorable benefit-risk profile anticipated at the time of regulatory approval/entry into market. However, the safety profile of medicine would continuously updates owing safety data from the postmarketing experience from public. If the rate of reporting of suspected adverse drug reactions (ADR) from public is line with the actual occurrence of ADRs, the time lapse for taking regulatory action can be reduced and thereby improving patient safety.
All health care professionals and consumers of pharmaceutical medicinal products are encouraged to be aware of this fact and observe/monitor for any possible adverse events, reactions, medication errors, or quality complaints of medicinal products and report the same to your respective national health authority.
This would accumulate safety evidence for medicinal products which in turn help health authorities to take regulatory actions at the earliest possibility for a better patient safety and overall public health.