Lithium Protocol

[Guest guest]

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> Hi, my name is Hollie. I too am Dr. Kloos's patient, and I am

>supposed to start lithium in a few weeks. I am supposed to be on it for 4

>weeks, taking (3) 300mg pills a day. And my first day is (3) 300mg pills

>with breakfast and (2) more pills through the day. I think that is an

>extremely high dose. I was just wondering what doses you had to take and

>how long.

>

Dear ThyCa Members:

It seems appropriate for me to clarify the use of lithium carbonate

in thyroid cancer; particularly since I was part of the team of

researchers characterizing its use [Koong SS, Reynolds JC, Movius EG,

Keenan AM, Ain KB, Lakshmanan MC, Robbins JR 1999 Lithium as a

potential adjuvant to 131I therapy of metastatic, well differentiated

thyroid carcinoma. J Clin Endocrinol Metab 84(3):912-916].

Purpose: to enhance the retention of radioactive iodine in thyroid

cancer tissue that is unable to hold on to it for very long. The

effective half-life of retention of radioiodine in

therapeutically-responsive thyroid cancer is usually 5-6 days.

Lithium may enhance this retention in those selected tumors with much

shorter half-lives; but has no beneficial effect on thyroid cancer

with normal half-lives of retention. Lithium does not enhance uptake

of iodine and cannot convert tumors which do not take up iodine into

tumors which do.

Method of administration: The key is to have an effective serum

level of lithium at the time of administration of the radioactive

iodine therapy. This is achieved by administering an oral bolus dose

of lithium (lithium carbonate) at midnight, 2 days before the

treatment day, followed by an oral dose every 8 hours (8 AM, 4 PM,

midnight). On the morning of admission, I obtain a trough serum

lithium level (just before the 8 AM dose) and adjust the lithium

dosing to bring the serum level into the range of 0.6 - 1.2 mEq/L.

At this point, the radioactive iodine therapy is administered. The

lithium is continued for a total of 5 days from the time of

radioactive iodine administration (in order to permit the half-life

to become prolonged to the maximal 5 day level). There is no value

in giving lithium earlier nor longer than outlined above.

Side effects: Acute administration of lithium may enhance sensations

of nausea or gastric upset. This is of particular concern when

attempting to prevent loss of the swallowed radioiodine dose. Any

lithium level above the 1.2 mEq/L level can be associated with

additional and worse side effects, making it very important to keep

the level correctly adjusted. This is also a good reason to avoid

prolonged administration of lithium longer than warranted for its

intended purpose.

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FOR EDUCATIONAL PURPOSES ONLY. IT IS NOT INTENDED, NOR SHOULD

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************************************************

B. Ain, M.D.

Professor of Medicine

Director, Thyroid Nodule & Oncology Clinical Service

Director, Thyroid Cancer Research Laboratory

Division of Endocrinology and Molecular Medicine

Department of Internal Medicine, Room MN524

University of Kentucky Medical Center

800 Rose Street, Lexington, Kentucky 40536-0298