About This Calculator
The Tymlos (abaloparatide) Dosing Calculator is a clinical support resource designed for healthcare professionals. It helps determine the appropriate dosing schedule, calculate the maximum remaining treatment duration, and identify key safety considerations for postmenopausal women with osteoporosis at high risk for fracture, based on the FDA-approved prescribing information.
Outputs
After entering patient-specific parameters, the calculator provides a clear, concise output summary that includes:
- Recommended Dose: The standard daily subcutaneous dose of Tymlos.
- Maximum Duration: The remaining allowable treatment duration in months, respecting the 24-month cumulative lifetime limit for PTH/PTHrP analogs.
- Renal Function Guidance: Specific recommendations based on the patient’s estimated glomerular filtration rate (eGFR).
- Safety Alerts: Immediate notification if a selected patient characteristic represents a contraindication to therapy.
How to Use
To use the calculator effectively, follow these steps:
- Confirm Indication: Check the box to confirm the patient is a postmenopausal woman with osteoporosis at high risk for fracture.
- Enter Renal Function: Input the patient’s eGFR or creatinine clearance (CrCl) in mL/min.
- Specify Prior Therapy: Indicate if the patient has previously used a PTH or PTHrP analog (e.g., teriparatide). If yes, enter the total duration of that therapy in months.
- Screen for Contraindications: Complete the checklist to screen for conditions that preclude the use of Tymlos.
- Calculate: Click the “Calculate Dose & Duration” button to generate the patient-specific recommendation.
Dosing Overview
The recommended dose of Tymlos is 80 mcg administered subcutaneously once daily in the periumbilical region. The injection site should be rotated daily.
The cumulative lifetime use of Tymlos and other PTH/PTHrP analogs should not exceed 2 years (24 months). The calculator automatically subtracts any prior therapy duration from this limit.
Switching and Sequential Therapy
After completing the treatment course with Tymlos, bone density gains may be lost. It is recommended to follow Tymlos with an antiresorptive agent, such as a bisphosphonate or denosumab, to maintain or further increase bone mineral density.
If a patient is switching to Tymlos from another PTH analog, the duration of the prior therapy must be known to ensure the 2-year cumulative lifetime limit is not exceeded.
Missed Dose
If a patient misses a dose of Tymlos, they should administer it as soon as they remember on the same day. Patients should be instructed not to administer more than one injection in the same day. They should resume their regular once-daily administration schedule the following day.
Safety Alerts
Abaloparatide caused a dose-dependent increase in the incidence of osteosarcoma in rats. The relevance of this finding to humans is unknown. Use of Tymlos is not recommended in patients at increased baseline risk for osteosarcoma, including those with Paget’s disease of bone, unexplained elevations of alkaline phosphatase, open epiphyses, or prior external beam or implant radiation therapy involving the skeleton.
Frequently Asked Questions (FAQ)
What is the maximum lifetime duration for Tymlos therapy?
The cumulative use of Tymlos and any other parathyroid hormone (PTH) or PTH-related peptide (PTHrP) analogs should not exceed 2 years (24 months) during a patient’s lifetime.
How does the calculator handle patients with prior teriparatide use?
The calculator requires you to input the number of months the patient was on teriparatide (or another PTH analog). It subtracts this duration from the 24-month lifetime limit to determine the maximum remaining duration for Tymlos therapy.
Is a dose adjustment needed for a patient with an eGFR of 45 mL/min?
No. According to the prescribing information, no dose adjustment is required for patients with mild or moderate renal impairment (eGFR ≥30 mL/min). However, Tymlos should be used with caution in patients with severe renal impairment (eGFR <30 mL/min) due to potential for increased drug exposure.
What happens if I select a contraindication in the tool?
If you select “Yes” for any of the contraindication checklist items, the calculator will display an error message indicating that Tymlos is contraindicated for that patient and should not be used.
Why is the first dose administered with the patient sitting or lying down?
Orthostatic hypotension (a sudden drop in blood pressure upon standing) can occur within 4 hours of the first few doses. Administering the first dose in a setting where the patient can sit or lie down helps manage any potential symptoms of dizziness or lightheadedness.
Can a patient take two doses of Tymlos in one day if they missed the previous day’s dose?
No. A patient should never take more than one dose in the same day. If a dose is missed, they should take it as soon as possible on that day and then resume their normal schedule the next day.
What should be done after the 2-year course of Tymlos is complete?
After completing therapy with an anabolic agent like Tymlos, it is recommended to transition to an antiresorptive agent (e.g., a bisphosphonate) to consolidate and maintain the gains in bone mineral density.
Does the calculator provide guidance for male patients with osteoporosis?
No. This calculator is based on the FDA-approved indication for Tymlos, which is specifically for the treatment of postmenopausal women with osteoporosis at high risk for fracture.
References
- TYMLOS® (abaloparatide) injection prescribing information. Radius Health, Inc. Available from: FDA.gov.
- Radius Health, Inc. TYMLOS® For Healthcare Professionals. Available from: tymlos-hcp.com.
- Miller PD, Hattersley G, Riis BJ, et al. Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial. JAMA. 2016;316(7):722–733. doi:10.1001/jama.2016.11136.
- Camacho PM, Petak SM, Binkley N, et al. American Association of Clinical Endocrinologists/American College of Endocrinology Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis—2020 Update. Endocr Pract. 2020;26(Suppl 1):1-46.
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