Drug Guide
Technetium Tc-99m Medronate
Classification
Therapeutic: Diagnostic imaging agent
Pharmacological: Radioisotope
FDA Approved Indications
- Bone scintigraphy for detection of metastatic bone disease, fractures, infections, and other bone abnormalities.
Mechanism of Action
Technetium Tc-99m Medronate is a radiopharmaceutical agent that localizes in bone tissue by chemisorption onto hydroxyapatite crystals, allowing for imaging of bones via gamma camera.
Dosage and Administration
Adult: Administer typically 20-30 mCi intravenously, with imaging performed 2-4 hours post-injection.
Pediatric: Dosage adjusted based on body weight and clinical judgment.
Geriatric: Adjust dose if renal function is compromised; no specific dose alterations mandated.
Renal Impairment: Use with caution; renal impairment may alter distribution and clearance.
Hepatic Impairment: No specific adjustments necessary.
Pharmacokinetics
Absorption: Administered intravenously; absorption is not applicable.
Distribution: Rapid distribution to bones and soft tissues.
Metabolism: Not metabolized; excreted unchanged.
Excretion: Primarily excreted via the kidneys in urine.
Half Life: Approximately 6 hours for Tc-99m; physical half-life of Tc-99m is about 6 hours.
Contraindications
- Known hypersensitivity to Technetium Tc-99m Medronate or its components.
Precautions
- Use caution in pregnant or breastfeeding women; exposure to radiation should be minimized.
- Adjustments may be necessary in patients with compromised renal function.
Adverse Reactions - Common
- Mild injection site pain, redness. (Uncommon)
- Nausea or transient discomfort. (Uncommon)
Adverse Reactions - Serious
- Allergic reactions including rash, itching, respiratory distress. (Rare)
- Radiation-induced tissue injury, especially with extravasation. (Very rare)
Drug-Drug Interactions
- None specifically known, but concurrent use of other radiopharmaceuticals should be managed carefully.
Drug-Food Interactions
- None significant.
Drug-Herb Interactions
- None identified.
Nursing Implications
Assessment: Monitor for allergic reactions, verify renal function, and ensure proper patient hydration.
Diagnoses:
- Potential for allergic reaction, risk of radiation exposure.
Implementation: Ensure proper dosing, safe handling, and patient preparation/education.
Evaluation: Assess for side effects, verify proper imaging quality, and monitor renal function if indicated.
Patient/Family Teaching
- Explain the purpose of the test and the importance of remaining still during imaging.
- Advise hydration post-test to facilitate excretion.
- Inform about minimal radiation exposure and precautions.
Special Considerations
Black Box Warnings:
- Radiation exposure risk; use only when necessary.
Genetic Factors: Not specifically known to be affected by genetic factors.
Lab Test Interference: Minimal; no significant interference expected.
Overdose Management
Signs/Symptoms: No specific antidote; symptoms may include radiation exposure effects such as nausea or tissue damage if extravasation occurs.
Treatment: Supportive care, symptom management, and observation.
Storage and Handling
Storage: Store unopened kits at 2-8°C; protect from light.
Stability: Stable until expiration date provided by manufacturer.