What baseline assessments and laboratory tests should be performed before initiating tirzepatide in an adult patient?

Baseline Screening Before Tirzepatide Initiation

Before starting tirzepatide, obtain baseline HbA1c, comprehensive metabolic panel including renal function, lipid panel, body weight/BMI, blood pressure, and screen for personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). 1

Essential Laboratory Tests

Glycemic Assessment

• HbA1c measurement is mandatory to establish baseline glycemic control and confirm type 2 diabetes diagnosis (HbA1c ≥6.5% in diabetes patients) 2, 3
• Fasting blood glucose should be obtained if HbA1c is unavailable or if acute glycemic assessment is needed 4

Renal Function Evaluation

• Serum creatinine and estimated glomerular filtration rate (eGFR) must be assessed, as patients with renal impairment face higher risk of adverse outcomes 5
• Tirzepatide can be used across the spectrum of renal function, but baseline documentation is critical for monitoring 3

Hepatic and Metabolic Panel

• Comprehensive metabolic panel including liver function tests, electrolytes, and glucose 5
• Baseline assessment helps identify patients at risk for electrolyte imbalances and dehydration from GI adverse effects 5

Lipid Profile

• Fasting lipid panel should be obtained as tirzepatide affects cardiovascular risk factors 3

Physical Measurements and Vital Signs

Anthropometric Data

• Body weight and BMI must be documented at baseline for all patients 1, 6, 4
• For obesity indication, confirm BMI ≥30 kg/m2 or ≥27 kg/m2 with at least one obesity-related complication 6

Cardiovascular Assessment

• Blood pressure measurement is essential, particularly in patients with established atherosclerotic cardiovascular disease 3
• Document baseline cardiovascular disease status including history of myocardial infarction, stroke, or coronary revascularization 3

Critical Safety Screening

Thyroid Cancer Risk Assessment

• Screen for personal or family history of medullary thyroid carcinoma (MTC) - this is an absolute contraindication 1
• Screen for Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) - also an absolute contraindication 1
• Consider baseline calcitonin measurement in high-risk patients, though not universally required 1

Gastrointestinal History

• Document history of gastroparesis, severe GI disease, or pancreatitis as these conditions may be exacerbated 5, 2
• Assess for diabetic retinopathy, as rapid glucose reduction may temporarily worsen this condition 2

Medication Reconciliation

Current Diabetes Medications

• Review all antihyperglycemic medications, particularly insulin and sulfonylureas, which may require dose reduction to prevent hypoglycemia 2, 7
• Confirm no concurrent use of other GLP-1 receptor agonists, as tirzepatide should not be combined with these agents 2

Concomitant Medications

• Document use of medications that may affect gastric emptying or interact with tirzepatide's mechanism 5

Special Population Considerations

Age and Comorbidity Assessment

• Confirm patient is ≥18 years of age for standard use 3, 6
• In patients with established atherosclerotic cardiovascular disease, document specific manifestations (coronary disease, peripheral artery disease, prior stroke) 3

Pregnancy and Reproductive Planning

• Assess pregnancy status and contraceptive use in women of childbearing potential, as tirzepatide is not recommended during pregnancy 1

Documentation for Compounded Products

Critical Safety Verification

• If using compounded tirzepatide, obtain the pharmacy label specifying exact concentration (mg/mL) to calculate the actual dose being administered 1
• Verify injection frequency is weekly, which is the standard FDA-approved schedule 1
• Document that patient understands compounded products lack FDA oversight for quality, sterility, and accurate dosing 1

Common Pitfalls to Avoid

• Do not initiate tirzepatide without confirming absence of MTC/MEN 2 history - this is a boxed warning contraindication 1
• Do not skip renal function assessment - patients with existing renal impairment have higher risk of complications from dehydration and electrolyte disturbances 5
• Do not assume all "100 unit" doses are equivalent - with compounded products, the actual milligram dose varies dramatically based on concentration (5 mg/mL = 5 mg dose; 15 mg/mL = 15 mg dose) 1
• Do not forget to plan for insulin/sulfonylurea dose reduction - hypoglycemia risk increases when tirzepatide is added to these medications 2, 7