From the Guidelines
Prolia (denosumab) should only be administered subcutaneously and not intramuscularly to ensure proper absorption and minimize potential adverse effects. The medication is specifically formulated and tested for subcutaneous administration, where it is slowly absorbed into the bloodstream through the fatty tissue under the skin 1. If Prolia is accidentally injected intramuscularly instead of subcutaneously, the patient may experience increased pain at the injection site, tissue damage, and potentially altered drug absorption which could affect efficacy.
Key Considerations
- The 60 mg pre-filled syringe of Prolia is designed specifically for subcutaneous injection in the upper arm, upper thigh, or abdomen.
- Intramuscular injection delivers medication directly into muscle tissue, which has different vascularity and absorption characteristics that could potentially change how quickly denosumab enters the circulation and how effectively it works.
- Proper administration technique includes pinching the skin and injecting at a 45-90 degree angle into the subcutaneous tissue, not the underlying muscle.
Potential Consequences of Intramuscular Injection
- Increased pain at the injection site
- Tissue damage
- Altered drug absorption
- Potential change in efficacy If an intramuscular injection occurs accidentally, healthcare providers should monitor the patient for adverse reactions and ensure proper technique is used for future injections, as supported by guidelines and studies on the use of adjuvant bisphosphonates and other bone-modifying agents in breast cancer 1.
From the Research
Administration of Prolia
- Prolia, also known as denosumab, is typically administered via subcutaneous injection, not intramuscularly.
- The studies provided do not specifically address the effects of administering Prolia intramuscularly instead of subcutaneously 2, 3.
Subcutaneous Administration
- Subcutaneous administration of denosumab has been shown to be effective in reducing the risk of vertebral, nonvertebral, and hip fractures in women with osteoporosis 2.
- A single subcutaneous dose of denosumab results in a dose-dependent, rapid, profound, and sustained decrease in bone turnover markers (BTMs) 2.
Potential Risks and Side Effects
- Denosumab is generally well tolerated, but may be associated with an increased risk of urinary infections and eczema 2.
- The mechanism of action of denosumab, which involves binding to the cytokine RANKL, reduces bone resorption by blocking osteoclast maturation, function, and survival 3.