(amikacin sulfate)

Brand

Veterinary: Amiglyde-V

Veterinary Availability:

• Injectable: 50 mg/mL

Brand

Human: Amikin

Human Availability:

• Injectable: 50 mg/mL, 250 mg/mL

*Note: Injectable form diluted in normal saline can also be used when nebulizing required.

Pharmacology

Amikacin is a semisynthetic derivative of Kanamycin. It is an aminoglycoside antibiotic that is considered bactericidal, and concentration dependent. It acts on susceptible bacteria by binding, irreversibly, to the 30S ribosomal subunit and inhibiting protein synthesis.

Amikacin has the same spectrum of activity as gentamicin and tobramycin, but it is less susceptible to enzymatic inactivation. This makes amikacin valuable in managing infections caused by Gram-negative bacilli resistant to gentamicin and tobramycin.

Amikacin’s use can include coverage against some aerobic Gram-positive bacteria,which include E. coli, klebsiella, proteus, pseudomonas, salmonella, enterobacter, serratia and mycoplasma.

The drug is almost exclusively eliminated by way of glomerular filtration when given in parenteral form.
Aminoglycosides do not readily cross the blood-brain barrier. However, they are able to cross placental barrier, and may cause nerve or nephrotoxic effects to the fetus. It is not recommended that these drugs be used in pregnant rats.

Indications

For use on serious Gram-negative infections involving skin and soft tissue, bone and joint, abdominal and urinary tract, and severe respiratory infections.

Drug Interactions or Contraindications

• Use cautiously with the following:
  • Loop diuretics such as furosemide (can increase ototoxicity)
  • With other aminoglycosides (increase nephrotoxicity)

• Per the manufacturer it is not a recommendation to mix amikacin in with other drug compounds. Give separately.
• For other interactions and contraindications check with a pharmacist.

Adverse Reactions

EENT: ototoxicity (loss of hearing)

CNS: lethargy, neuromuscular blockade, facial edema, tremors, pain/inflammation at injection site.

Resp: bronchoconstriction and/or bronchospasm can occur when nebulizing, but are reportedly rare

GI: Affects GI flora

GU: nephrotoxicity (oliguria,proteinuria)

Skin: itching, swelling

Other: loss of coordination

*Note: all aminoglycosides have the potential for causing ototoxicity, nephrotoxicity and neuromuscular blockade due to high serum and tissue concentrations, as well as prolonged use. This is especially prevalent when given by parenteral administration (e.g., IM, IV, SQ) due to systemic absorption. Studies have shown no evidence of toxicity when nebulized in therapeutic doses even with prolonged use. The lack of toxicity seen with nebulized aminoglycosides may be due to minimal or no systemic absorption, having lower unsustain serum concentrations due to a lower dosage used, and being directly delivered to the area of infection. A noted concern of prolonged or repetitive nebulizing of antimicrobials, such as the aminoglycosides, is the potential for the overgrowth of resistant organisms.^{1, 2, 3}

Dosage Recommendations

Injectable for Nebulization: 10 mg in 10 mL water for 15 minutes to 30 minutes, q6hr to q12hr   ⁴².
(*note: normal saline preferred instead of water)

or

2 mg/kg to 5 mg/kg, SQ or IM, q8hr to q12hr  ¹

or

10 mg/kg, SQ or IM, q12hr  ²⁷

or

5 mg/kg to 15 mg/kg, SQ, IM, IV, q8hr to q12hr (Administer with fluid therapy)  ^34, 41, 44

or

16 mg/kg, SQ, IM, q8hr to q12hr (Administer with fluid therapy) ^35, 42, 44

or

10 mg/kg to 20 mg/kg total per day divided q8hr to q24hr; SQ, IM  ²

or

10 mg/kg to 20 mg/kg per day  ¹¹

or

5 mg/lb, SQ or IM, BID or TID, for 7 to 14 days (as recommended on RMCA Drug Chart)

Considerations

• Use cautiously in animals with impaired renal function. Monitor weight.
• Be sure pet rat has access to plenty of fluids, or fluid containing foods (e.g., fruits that are juicy), while receiving the drug in order to minimize chemical irritation in renal tubules.
• Give yogurt, Lactobacillus capsules/granules, or Bene-Bac to help maintain normal gut flora.
• Watch for loss of balance.
• In treating suspected polymicrobial infections, where a broader coverage may be needed, synergistic or combination drugs may be used. The following drugs may be seen used simultaneously with amikacin: ampicillin, amoxicillin, penicillin, fluoroquinolones (e.g., enrofloxacin or orbifloxicin), cephalosporins, trimethoprim-sulfa, and metronidazole. ¹
• Please note that it is imperative to discuss the changing or adding of any medications during your rat’s treatment with your veterinarian to prevent future resistance of microbes to the drugs prescribed.
• Store injectable amikacin vial in refrigerator unless otherwise directed.

References

1. Campbell, P., & Saiman, L. (1999). Use of aerosolized antibiotics in patients with cystic fibrosis. Chest, 116(3), 775-88. Retrieved October 6, 2010, from http://chestjournal.chestpubs.org/content/116/3/775.long
2. Cohn, L. (2009). Inhalant therapy: Finding its place in small-animal practice. Veterinary Medicine, 104(7), 336-341. Retrieved October 6, 2010, from http://veterinarymedicine.dvm360.com/vetmed/article/articleDetail.jsp?id=608394
3. Prober, C., Walson, P., Jones, J., & Committee on Infectious Diseases and Committee on Drugs. (2000). Technical report: precautions regarding the use of aerosolized antibiotics. Pediatrics, 106(6), e89. Retrieved October 6, 2010, from http://pediatrics.aappublications.org/cgi/content/full/106/6/e89