Infants also tend to have a larger volume of distribution due to their higher concentration of extracellular fluid, where aminoglycosides reside.The elderly tend to have amikacin stay longer in their system; while the average clearance of amikacin in a 20-year-old is 6 L/hr, it is 3 L/hr in an 80-year-old.Clearance is even higher in people with cystic fibrosis.In people with muscular disorders such as myasthenia gravis or Parkinsons disease, amikacins paralytic effect on neuromuscular junctions can worsen muscle weakness. Adverse effects
Side-effects of amikacin are similar to those of other aminoglycosides. Kidney damage and ototoxicity (which can lead to hearing loss) are the most important effects, occurring in 1–10% of users. The nephro- and ototoxicity are thought to be due to aminoglycosides tendency to accumulate in the kidneys and inner ear. Amikacin can cause neurotoxicity if used at a higher dose or for longer than recommended. The resulting effects of neurotoxicity include vertigo, numbness, tingling of the skin (paresthesia), muscle twitching, and seizures. Its toxic effect on the 8th cranial nerve causes ototoxicity, resulting in loss of balance and, more commonly, hearing loss. Damage to the cochlea, caused by the forced apoptosis of the hair cells, leads to the loss of high-frequency hearing and happens before any clinical hearing loss can be detected. Damage to the ear vestibules, most likely by creating excessive oxidative free radicals.
Such patients most likely have a bladder storage disorder that impacts their nighttime voiding or a sleep disorder. Nocturnal bladder capacity (NBC) is defined as the largest voided volume during the sleep period.Decreased NBC can be traced to a decreased maximum voided volume or decreased bladder storage. Decreased NBC can be related to other disorders such as:

benign prostatic hyperplasia (BPH), also known as prostate enlargement
neurogenic bladder dysfunction
learned voiding dysfunction
anxiety disorders
urinary tract infection
certain pharmacological agents. Mixed cause
A significant number of nocturia cases occur from a combination of causes. Mixed nocturia is more common than many realise and is a combination of nocturnal polyuria and decreased nocturnal bladder capacity. In a study of 194 nocturia patients:
7% were determined to solely have nocturnal polyuria
57% solely had decreased NBC
36% had a mixed cause of the twoMultifactor caused nocturia is often unrelated to an underlying urological condition. Mixed nocturia is diagnosed through the maintenance and analysis of bladder diaries of the patient. Assessment of cause contributions are done through formulas. Management
Lifestyle changes
Although there is no cure for nocturia, many actions can manage the symptoms. Prohibiting caffeine and alcohol intake. Both are diuretic. Beverage consumption regulation. In regard to nocturia, this specifically means avoiding consuming fluids for three or more hours before bedtime so giving the bladder less fluid to store overnight. This especially helps people with urgency incontinence. However, one study regarding geriatric patients showed that it reduced voiding at night by only a small amount and is suboptimal for managing nocturia in older people.