For intravenous administration, ertapenem should be reconstituted with which diluent?

• A. 3.2 mL lidocaine without epi
• B. 10 mL NS
• C. 5 mL sterile water
• D. Normal saline 0.9%

Answer: (B)

When preparing ertapenem for IV use, you want an isotonic diluent in the correct volume to avoid harming the patient’s blood cells or vessels. Ertapenem powder is reconstituted with 10 mL of normal saline (0.9% NaCl). This provides a safe, compatible solvent for IV administration and sets up the drug for the usual subsequent step of diluting into an appropriate infusion volume for the actual IV dose.

Using lidocaine without epinephrine is typically reserved for IM injections to reduce pain and isn’t appropriate for IV reconstitution. Sterile water for injection is hypotonic and can cause hemolysis if infused IV. So the best choice for intravenous reconstitution is 10 mL of normal saline.