Should a Lithium Level Be Checked Before Starting Lithium?
No, a baseline lithium level is not necessary before initiating lithium therapy because the patient has not yet been exposed to the medication—there is no lithium in their system to measure. However, comprehensive baseline laboratory monitoring is mandatory before starting lithium, and facilities for prompt serum lithium determination must be available once treatment begins.
Required Baseline Laboratory Assessment
Before initiating lithium therapy, the following tests are mandatory 1:
- Complete blood cell counts 1
- Thyroid function tests (TSH, free T4) 1
- Urinalysis 1
- Blood urea nitrogen (BUN) 1
- Serum creatinine 1
- Serum calcium levels 1
- Pregnancy test in females of childbearing age 1
These baseline values establish the patient's organ function status before lithium exposure and provide reference points for future monitoring 1.
Critical Pre-Treatment Requirements
Lithium should only be initiated in settings where personnel and facilities for close clinical and laboratory monitoring are available 1, 2. This is non-negotiable because lithium toxicity can occur at doses close to therapeutic levels, and the drug has a narrow therapeutic window 2.
Post-Initiation Monitoring Protocol
Once lithium is started, aggressive monitoring is required 2:
- Serum lithium levels twice weekly during the acute phase until both serum level and clinical condition stabilize 2
- Blood samples should be drawn 8-12 hours after the previous dose (trough levels) 2
- Target therapeutic range for acute mania: 1.0-1.5 mEq/L 2
- Target maintenance range: 0.6-1.2 mEq/L 2
Long-Term Monitoring Requirements
After stabilization, ongoing monitoring every 3-6 months includes 1:
- Serum lithium levels
- Renal function (BUN, creatinine)
- Thyroid function tests
- Urinalysis
During uncomplicated maintenance therapy, lithium levels should be monitored at least every two months 2.
Clinical Rationale for Lithium in This Patient
Given the family history of bipolar disorder (maternal grandmother) and failed medication trials, lithium represents an evidence-based first-line option 3, 1. Lithium is the only FDA-approved medication for bipolar disorder in patients age 12 and older and has superior evidence for long-term efficacy compared to other mood stabilizers 3, 4. It reduces suicide risk 8.6-fold and prevents both manic and depressive episodes in non-enriched trials 3.
Common Pitfall to Avoid
Do not confuse baseline laboratory assessment with checking a "lithium level"—the latter only becomes relevant after the patient has been taking lithium for several days. The critical error would be delaying treatment initiation while waiting for unnecessary pre-treatment lithium levels, when the focus should be on comprehensive organ function assessment and ensuring monitoring capabilities are in place 1, 2.