Medications That Should Not Be Diluted in Dextrose Solutions
Amphotericin B must not be reconstituted or diluted with saline solutions, as this causes precipitation of the antibiotic; it requires dilution exclusively in 5% Dextrose Injection with pH above 4.2. 1
Critical Drug-Specific Contraindications
Amphotericin B (Definitive FDA Guidance)
- Do not reconstitute with saline solutions - the FDA label explicitly states this causes precipitation 1
- Must use Sterile Water for Injection (without bacteriostatic agents) for initial reconstitution to 5 mg/mL 1
- Further dilution requires 5% Dextrose Injection USP with pH above 4.2 (1:50 dilution to achieve 0.1 mg/mL) 1
- If commercial dextrose has pH below 4.2, add 1-2 mL of phosphate buffer before diluting amphotericin B 1
- Any diluent other than recommended or presence of bacteriostatic agents (e.g., benzyl alcohol) causes precipitation 1
Radiopharmaceuticals (Technetium-99m Compounds)
- Technetium-99m radiopharmaceutical kits should not be diluted with 5% dextrose - this produces radiochemical impurities 2
- Affected compounds include Tc-99m tetrofosmin, MDP, stannous colloid, and mebrofenin 2
- Dextrose dilution creates Tc-99m-dextrose complexes causing altered biodistribution with cardiac blood-pool activity, soft-tissue background, and abnormal renal/gallbladder uptake 2
- Normal saline is the required diluent for these radiopharmaceuticals 2
Medications Requiring Dextrose-Free Diluents
Oncologic Infusion Reactions Management
- Ranitidine for infusion reactions should be diluted in 5% dextrose, but diphenhydramine and other antihistamines can use alternative diluents 3
- Dopamine (400 mg in 500 mL) and vasopressin (25 U/250 mL) for refractory hypotension may use either 5% dextrose or normal saline 3
Clinical Context: When Dextrose Solutions Are Problematic
Electrolyte Disturbances
- Concurrent medications dosed intermittently should be mixed in sodium chloride solutions rather than dextrose to reduce glucose variation in critically ill patients receiving insulin infusions 3
- Changing drug diluent default from D5W to saline increases hypernatremia (27.3% vs 14.6%) and hyperchloremia (36.9% vs 20.4%) but doesn't affect glucose control or mortality 4
Radiopharmacy Quality Control
- Using dextrose instead of saline for Tc-99m kit preparation results in confusing scintigrams with both normal and grossly abnormal findings 2
- Not all radiochemical kits prepared with dextrose will show impurities, creating diagnostic confusion 2
Common Pitfalls to Avoid
- Never assume all intravenous medications can use dextrose as a diluent - always verify drug-specific requirements 1, 2
- Check pH requirements - amphotericin B requires dextrose pH >4.2, necessitating buffer addition if commercial dextrose is too acidic 1
- Avoid bacteriostatic agents - amphotericin B preparation requires strict aseptic technique without preservatives, as these cause precipitation 1
- In nuclear medicine, review preparation procedures immediately if scintigrams show unexpected biodistribution patterns, as dextrose contamination may be the cause 2