Fentanyl Vs. Alfentanil in Acidosis

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fentanyl has a pka of 8.4 and is 91% ionized at a ph of 7.4. alfentanil has a pka of 6.5 and is 11% ionized at a ph of 7.4, and also has a lower volume of distribution than fentanyl. i believe alfentanil is more lipophillic but don't quote me on that. if a patient is in metabolic acidosis say ph of 7.0 wouldn't the alfentanil become even more unionized

thanks,

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fentanyl has a pka of 8.4 and is 91% ionized at a ph of 7.4. alfentanil has a pka of 6.5 and is 11% ionized at a ph of 7.4, and also has a lower volume of distribution than fentanyl. i believe alfentanil is more lipophillic but don't quote me on that. if a patient is in metabolic acidosis say ph of 7.0 wouldn't the alfentanil become even more unionized

thanks,

first thought? with a ph of 7.0, selection of narcotics wouldn't be my biggest concern. ;)

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First thought? With a pH of 7.0, selection of narcotics wouldn't be my biggest concern. ;)

just a hypothetical number it is more due to the environment acidic/basic rather than strictly a pH number

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Specializes in Anesthesia.
First thought? With a pH of 7.0, selection of narcotics wouldn't be my biggest concern. ;)

LOL... my thoughts too. No need for narcs in a dead person......

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