Question

Sally is diagnosed with pneumonia after examination by her doctor. Her symptoms are cough and shortness of breath. Given the severity of her symptoms, the doctor feels that treatment with tobramycin should be started immediately. A therapeutic concentration of 4mg/L is desired as quickly as possible. Tobramycin distributes to extracellular fluid and has a t_1/2 of 7.5 hours. What is the loading dose for the required?

Volume of Distribution into extracellular fluid in a 70kg person is 14L.

Answer 1

What is pneumonia:

It is a inflammation of lung parenchyma .

- it is a infection of lung with a range of possibles causes and it can be serious and life threatening disease.

- it normally start with infection

- lungs become inflammed and the tiny air sacs or alveoli fillup with fluid.

types :

1. Lobar pnuemonia
2. broncho pnuemonia
3. community acquired pneumonia.
4. hospital acquired pneumonia.

causes:

• Bacterial infection
• viral infection
• fungi infection

Symptoms :

• Fever
• cough
• rust colored sputum
• dyspnea.
• chest pain
• elivated WBC.
• chills etc.

Tobramycin to treat pneumonia:

• The actual dose of tobramycin is 40mg / ml
• loading dose: loading dose of inj .tobramycin is 1.5 to 2mg /kg iv .
• in case of life threatening lung infection about 4-5mg /kg / 8hours given in a 3-4 equivalent doses.and maitenance dose given in a 3mg /kg as per the clinical condition of the patient .
• Here in the above given question ,the tobramycin distribute to ectracellular fluid and has half life of 7.5 hrs .
• for the 70 kg person ,the extracellular distribution is 14litres and loading dose of tobramycin required for this patient is
• PRECAUTIONS :
• To prevent incresed toxicity due to excess of tobramycin in blood level,dosage should not exeed more than 5mg / kg unless serum levels are monitored.
• limiting the dosage of tobramycin therapy may help to limit toxicity ,once patient is stable at least 48 hrs less toxic be considered according to microbiology sensitivity data.

A peak tobramycin levels to be measured one hour after the second dose is started .