Why Lutetium-177 Infusions Cause Nausea
Nausea during Lu-177 infusions is primarily caused by the co-infused amino acid solution (lysine and arginine), not the radiopharmaceutical itself. The amino acids induce metabolic acidosis and electrolyte imbalances that trigger nausea in the majority of patients 1.
Primary Mechanism: Amino Acid-Induced Metabolic Acidosis
The nausea occurs through the following mechanism:
Amino acids (25g lysine + 25g arginine) are co-infused in 2L of normal saline to protect the kidneys by competitively inhibiting proximal tubular reabsorption of the radiopharmaceutical 1
This large amino acid load causes metabolic acidosis with associated electrolyte imbalances (hyperkalemia, hypernatremia) that directly trigger nausea and vomiting 1
Nausea occurs in the majority of patients receiving peptide receptor radionuclide therapy with Lu-177, making it one of the most common acute side effects 1
Clinical Management Algorithm
Prophylactic antiemetics should be given before amino acid infusion:
- Administer metoclopramide or ondansetron prior to starting the amino acid infusion 1
- Repeat antiemetic doses as needed during or after treatment 1
If nausea develops during treatment:
- Hydrate with normal saline to correct metabolic acidosis 1
- Consider repeating corticosteroid administration if needed 1
- Monitor for electrolyte imbalances (hyperkalemia, hypernatremia) 1
Dietary modifications:
- Avoid large meals on the day of treatment, as they exacerbate amino acid-related nausea 1
- Ensure adequate hydration (at least 500ml water 12 hours before treatment) 1
Important Clinical Pitfalls
The amino acid infusion is mandatory despite causing nausea because the kidneys are the dose-limiting organs for Lu-177 therapy, and without amino acid protection, severe nephrotoxicity will occur 1
In patients with cardiac insufficiency, reduce amino acid volume (e.g., 25g lysine or arginine in maximum 1L saline instead of 2L) to prevent volume overload while maintaining renal protection 1
Nausea rates can be substantially reduced by optimizing the amino acid formulation and infusion technique—one study showed nausea rates decreased from 61% to 27% after revising the amino acid formulary 2