Procedure Logs

C3.1 R4(e): Perform & document a pharmacokinetic interpretation (OTHER drug – Lithium)

MH is a 12 year old girl with bipolar disorder who is currently being treated with lithium citrate equivalent as lithium carbonate 450 mg once daily as a part of her drug therapy.

Patient’s lithium came back as 0.5 mmol/L (aim for 0.8-1.0) for active mania.

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MH is currently receiving lithium citrate solution dosed in equivalents of lithium carbonate. However, upon discharge she will likely switch to a capsule formulation. Thus, it is suggested that we dose to the nearest dose available in capsules. For MH this would be 750 mg/day.

As MH is currently receiving 450 mg, I suggest we increase to 600mg and reassess the lithium concentration. I do not currently recommend a 750 mg increase from 450 mg, to allow us to keep a close monitoring on MH and ensure that she does not experience any lithium toxicities. Based on this recommendation of 600 mg daily, I recalculated that the 12-hour post-level concentration predicted would be 0.7 mmol/L.

I spoke with the attending psychiatrist and wrote the subsequent note in the chart.

 

Clinical Pharmacist Note, re: lithium levels

Oct 28, 2016

14:00

Patient is currently receiving lithium citrate equivalent to lithium carbonate 450 mg PO QHS (since October 24, 2016). Level taken appropriately after the 4th dose (October 24th at 09:40) was 0.5 mmol/L (usual target is 0.8-1.0 mmol/L). A dose increase to lithium citrate equivalent to lithium carbonate 750 mg PO QHS may be necessary to target 0.8-1.0 mmol/L. At this time it would be appropriate to try an increase of lithium citrate equivalent to lithium carbonate 600 mg PO QHS, which would likely result in a 12-hour post-level of 0.7 mmol/L. Discussed with attending psychiatrist.

 

– Iona Berger, Pharmacy Resident

 

Update: Patient has been on lithium citrate equivalent to lithium carbonate 600 mg PO QHS as suggested as above and a post-12 hour level after the 4th dose of the new dosing regimen was taken. As I had predicted (yay!) the level came back as 0.7 mmol/L. Based on this we continued with our plan as stated above to increase the dose to lithium citrate equivalent to lithium carbonate 750 mg PO QHS.

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