A 2015 review article discusses the use of intravenous (IV) medications in the intramuscular (IM) or subcutaneous (SQ) route. Many IV medications are not intended for administration via the IM or SQ routes due to safety concerns. IV medications are formulated for rapid absorption and effect when administered intravenously. If given via other routes, the medication may not be adequately or rapidly absorbed, resulting in suboptimal effect or even failure of the treatment. In some cases, the local vasoconstrictive or other adverse effects of the medication at the injection site could cause tissue damage if not diluted or administered properly via IM or SQ routes. However, for some IV medications, literature evidence has shown the IM or SQ routes can be options with comparable efficacy and safety when administered carefully following proper preparation guidelines (see Table 1). Medications intended for IV use but considered for IM or SQ administration should be carefully diluted according to product information or literature evidence to reduce local concentration and potential for tissue injury. They should be administered slowly and with frequent monitoring to ensure safe absorption. The anatomical site of IM injection (e.g., vastus lateralis versus deltoid) should also be considered when administering medications via IM route, as greater absorption may be observed at one site over the other. [1]

A 2020 observational study analyzed subcutaneous drug administration in 120 palliative care patients at a Danish hospice. Researchers reviewed records retrospectively and prospectively observed 20 patients. They found subcutaneous drugs were used in 90% of patients. A total of 30 drugs were administered subcutaneously, with 10 (33%) authorized and 20 (67%) used off-label via this route (see Table 2). Of the off-label drugs, 11 had little support reported. Drugs were given via injection or continuous infusion pump, with off-label drugs making up 57% of continuous infusions. Over 9,000 subcutaneous administrations were recorded. Adverse reactions occurred in 7 patients, consisting of 11 minor skin reactions; only 2 patients stopped drugs due to reactions. The overall low frequency and mildness of reactions suggested acceptable safety and tolerability, even for off-label drugs. The study concluded that while two-thirds of subcutaneous drugs used were off-label, this was established practice due to lack of alternatives, and recommended improved registration and reporting of off-label use, as well as initiatives to study best practices and strengthen evidence through clinical research, when possible.

A search of the published medical literature revealed 2 studies investigating the researchable question:

What are medications usually administered IV that can be given IM or SQ, with guidelines on volume & diluent?

C - Multiple studies with limitations or conflicting results  Read more→