When do you draw a gentamicin peak and trough

In addition, aminoglycosides have an extended post-antibiotic effect PAE which is defined as the time period that surviving bacteria, following exposure to an antibiotic, cannot metabolize or multiply even though extracellular antibiotic is no longer present.

The duration of PAE is approximately hours in the immunocompromised patient. The uptake of aminoglycosides occurs in the renal tubular cells and is a saturable process; therefore, larger doses would not be expected to be any more nephrotoxic than smaller doses. Vaccines content by guidance area.

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Events index Webinars Conferences Search Events. As aminoglycoside uptake into bacteria is oxygen dependent, they are therefore not active against anaerobes. Gentamicin is commonly used to treat urinary tract infections, sepsis, intra-abdominal infections, endocarditis, pelvic inflammatory disease and complicated skin, bone and soft tissue infections.

It is often used for more serious Gram-negative infections, or in combination with a broad spectrum beta lactam antibiotic to provide coverage against Gram-positive bacteria. Gram-negative bacteria can be difficult to treat because of the complex nature of their cell wall. Beta lactam antibiotics active against the cell wall e. Amino glycosides may cause auditory or vestibular nerve damage in infants if used during the second or third trimesters of pregnancy, and should be avoided if possible.

If treatment is required, gentamicin is the preferred aminoglycoside because, although it does cross the placenta, it has not been associat ed with developmental toxicity [4].

It can also be used in patients who are breastfeeding [5]. Gentamicin is contr aindicated in patients with myasthenia gravis, where neuromuscular transmission may be impaired. It should also be avoided in patients taking drugs that can cause nephrotoxicity e. Gentamicin is usually given by slow bolus injection over two to three minutes or via intravenous infusion over 30 minutes.

Ideal body weight IBW should be used in all non-obese patients, unless actual body weight is lower; in these patients actual body weight should be used. Aminoglycosides are not distributed into adipose tissue, as they are highly hydrophilic. Gentamicin and other aminoglycosides are cleared by the kidneys, and it is therefore important that renal function is assessed before treatment starts. It is important to ensure an accurate renal function value is used to reduce the risk of toxicity.

For overweight patients, IBW should be used when calculating renal function. The majority of patients given gentamicin will use the following calcuations, rather than their actual body weight ABW. Aminoglycosides also have a significant post-antibiotic effect and cause inhibition of bacterial growth after only a brief exposure. This means periods of low drug concentrations are used to minimise drug toxicity without reducing efficacy. Extended interval regimens e. If impaired renal function is a concern, a level should be obtained before the 2nd dose.

Theophylline Either a trough or peak level will provide adequate information regarding dosing. A theophylline trough level should be obtained 0 - 2 hours before the scheduled dose, and the dose administered without awaiting the result. Consider writing the theophylline order to reflect times of administration to be at 4 am, 12 pm and 8 pm. This would allow the peak level to be drawn with morning labs if the patient is on a q 8 h schedule. When initiating therapy or changing the dose serum theophylline levels should be obtained hours the first dose or change in dose.