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Suggest Treatment For Osteomyelitis And Infection In Tendon

Posted on Mon, 9 Mar 2015

Question: patient is on Flagyl 1000 mg PO BID. Is this an adequate dose for a 200 pound 16 year old boy with osteomyelitis and infection in tendon? Also, what are your thoughts on duration of treatment with antibiotic for osteomyelitis.

Answered by Dr. Diptanshu Das (25 minutes later)

Brief Answer:
Dose seems more than required. Choice of antibiotic not proper.

Detailed Answer:
Thanks for asking on HealthcareMagic.

Flagyl contains metronidazole which is effective in preventing or treating anerobic infections. The ideal dose is 7.5 mg/kg given every 6 hours. For a 200 pound or 90 kg child, the correct dose should be 675 mg per dose. Since Flagyl tablet comes in dose of 400mg per tablet, one and a half tablet should be reasonable to be given. But 1000 mg seems to be high. You should discuss about the same with your doctor.

Some other antibiotic coverage needs to be given along in case of osteomyelitis. Oral antibiotics that have been proven to be effective include clindamycin, rifampin, trimethoprim-sulfamethoxazole, and fluoroquinolones. The choice of antibiotics depends upon the identification of pathogens from bone cultures at the time of bone biopsy or debridement, or upon the clinical judgement of the doctor. A 4 to 6-week course of antibiotics is needed.

Hope that helps.

If you found my answer to be helpful, please close the thread with a positive review and a 5 star rating.

Regards
Dr. Diptanshu Das

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Diptanshu Das (15 minutes later)

HI: He is on 1000 mg q 12 hours for a total of 2000 mg daily. This comes below the 7.5 mg/kg q 6 hours (four times a day). iF he was taking 7.5 mg/kg every six hours the total daily dose is 2700 mg (675 x 4). so i was just wondering about th fact that his total dose is 2000 mg vs 2700 mg. thanks

Answered by Dr. Diptanshu Das (1 hour later)

Brief Answer:
You have probably confused pounds and kgs

Detailed Answer:
Thanks for writing back.

The dosage that I have mentioned is /kg/dose and not /lb or pound. I think there you got the calculation wrong. A 200 pound person weighs about 90 kg. I have made the calculation in relation to the same.

Regards
Dr. Diptanshu Das

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Diptanshu Das (14 hours later)

HI: I did not confuse the mg and the pounds. The dose he is on is q 12 hours. If the recommended dose is 7.5mg/kg per dose and the doses are 4 times a day (q 6 hours) then the total dose recommended is 675mg x 4 which comes to 2700. He is on 1000 q 12 hours, which is 2000 mg total daily. I am asking because I am worried that this is significant. Others have told me that just 2000 mg is enough, even though that is not what is in the package insert. So that is why I asked. Incidentally, he has fusibacterium nucleatum…so the flagyl was chosen due to it's ability to get this anaerobe. My concern is whether the dose is adequate.
THANKS, XXXX

Answered by Dr. Diptanshu Das (2 hours later)

Brief Answer:
The dose is adequate but a thrice daily dosing would be preferred.

Detailed Answer:
Thanks for writing back.

Each medicine has a certain duration of action. For Flagyl, a thrice daily or four times daily dose is advisable. I would not recommend twice daily dosing. Otherwise 2000 mg per day is more than adequate.

Hope that helps.

Regards
Dr. Diptanshu Das

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Diptanshu Das (6 hours later)

Okay thank you for that. can you explain just a little more as to why the recommended dose would get a person up to 2700, at his weight, while he is at 2000? I've seen dosages of 750 q 8 hours in the literature so I know people go up to higher doses than 2000. Thank you, any added thoughts would be helpful.

Answered by Dr. Diptanshu Das (1 hour later)

Brief Answer:
It does not really matter

Detailed Answer:
I understand that you are trying to connect the dots to the best of your abilities but the lack of medical knowledge is still acting as a barrier. Your child weighs 90 kg (approx). 7.5x90=675mg. So, the preferred dose would have been 675 mg per dose whether you give it thrice or four times a day. A thrice daily dose will approximate to around 2000 mg per day and a four times a day regimen will give around 2700 mg per day. There are ranges of effectivity and it is not a single pinpoint dose that is always required.

Most commonly we prescribe 400mg per dose and it works well.

Regards
Dr. Diptanshu Das

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Diptanshu Das (12 minutes later)

HI: Thanks very much for your reply. I am actually a doctor myself, which is probably why I have more concern. It is not always easy to get doctors to think about things and answer questions thoughtfully, as the tendency sometimes is to be overly confident and not reflective. So it is very helpful to speak w/ someone outside of the situation. There is obviously a lot at stake and I appreciate you answering. I don't think my doctor will agree to go to 3 times a day but maybe I should ask him. Sometimes doctors do get offended when they are questioned so it is always a gamble.
THANKS!

Answered by Dr. Diptanshu Das (1 hour later)

Brief Answer:
Glad to hear that you found my answer helpful

Detailed Answer:
I assume that the treatment is being administered by a orthopedician or may be a surgeon. Unfortunately, doctors apart from pediatricians are often not quite familiar with dosage principles. So, I guess asking them would not really be helpful anyway.

Hope that my answer helped. In case it did, please close the thread with a positive review and a 5 star rating.

Regards
Dr. Diptanshu Das

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Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar