Welcome to the FDA Side Effects Update. This series is designed to keep you informed about the latest safety advisories and newly documented side effects of your medications. In this installment, we’re highlighting a safety update concerning four osteoporosis medications: Bonsity, Forteo, Teriparatide injection, and Tymlos, as well as a related update for the hypoparathyroidism medication Yorvipath. 

How to Read This Report+

This report is prepared using the most recent information posted in the SrLC database. It highlights recent safety labeling changes. It includes only newly reported side effects and safety information; additional side effects and warnings will appear on the drug label. Not all recent changes to the SrLC database or the label may be listed here. For all changes and the complete list of warnings and side effects, please click on the drug label link.

Each of the items (approval and update dates, drug names, etc.) contained in this report are obtained from the SrLC. The side effects and medication descriptions are simplified and made clearer, if needed. Sometimes, additional sources, like a medical dictionary, may be used to translate technical medical phrases. Other sources (company news, FDA press releases, etc.) may be used to learn about some label changes.

Updated Side Effects for Certain Parathyroid Hormone Drugs

Two types of parathyroid hormone drugs have received safety updates: four that treat osteoporosis and one that treats hypoparathyroidism. 

Osteoporosis Drugs

Osteoporosis is a condition in which bones lose mass and strength, making them more vulnerable to fractures. 

Four tiny parathyroid glands — each about the size of a grain of rice and located behind the thyroid gland in the neck — produce parathyroid hormone (PTH), which helps regulate calcium and phosphorus levels in the body. The four osteoporosis treatments featured in this installment mimic the activity of PTH or a related hormone to stimulate new bone formation. For this reason, they’re known as anabolic, or bone-building, osteoporosis drugs. The medication is self-administered daily with a subcutaneous injection using a prefilled pen.

Usually taken for about 2 years, a parathyroid hormone osteoporosis medication is often followed by another therapy, such as a bisphosphonate, to maintain bone density gains and prevent bone loss. 

Hypoparathyroidism Drugs

When the parathyroid glands don’t produce enough parathyroid hormone (PTH), the condition is called hypoparathyroidism, or hypopara. The disorder can be treated with Yorvipath (palopegteriparatide), a recently approved medication designed to replace the missing PTH. Yorvipath is self-administered once daily as a subcutaneous injection using a prefilled pen.

In April 2026, the FDA sent notifications (as mentioned in this letter regarding Forteo to Eli Lilly) informing sponsors of parathyroid hormone drugs (four osteoporosis treatments and one hypoparathyroidism treatment) to update drug labels with safety information about the risk of hypersensitivity reactions. This risk was earlier flagged as a potential safety concern in the October-December 2024 New Safety Information or Potential Signals of Serious Risks from FDA Adverse Event Reports.

Bonsity (teriparatide) injection, solution

Initial FDA Approval: 1987 (active ingredient); 2025 (this product)
Side Effect Update Date: August 3, 2026 
Medication Description: Treats osteoporosis in people at high risk for bone fractures. This medication is a synthetic parathyroid hormone (PTH) that helps stimulate the growth of new bone and improve bone strength. 
Updated Side Effects/Safety Information: An updated warning that serious allergic reactions, including anaphylaxis, angioedema (swelling that can affect the face, lips, tongue, or throat), and hives, have been reported in people treated with parathyroid hormone (PTH) analogs, including Bonsity. Patients should discontinue Bonsity and seek medical attention if experiencing signs of an allergic reaction, such as facial swelling, rapid heartbeat, breathing problems, itching, rash, hives, fainting, dizziness, or lightheadedness. Bonsity should not be used by anyone who has previously had a severe allergic reaction to teriparatide or any of the inactive ingredients in the medication.
FDA Safety Announcement: Bonsity FDA Safety Label Change and Revised Drug Label
The revised drug label contains a complete list of FDA-approved indications, side effects, warnings, and more.

Forteo (teriparatide) injection, for subcutaneous use

Initial FDA Approval: 1987 (active ingredient); 2002 (this product)
Side Effect Update Date: August 3, 2026 
Medication Description: Treats osteoporosis in people at high risk for bone fractures. This medication is a synthetic version of the parathyroid hormone (PTH), which helps to stimulate the growth of new bone and improve bone strength. 
Updated Side Effects/Safety Information: An updated warning that serious allergic reactions, including anaphylaxis, angioedema (swelling that can affect the face, lips, tongue, or throat), and hives, have been reported in people treated with parathyroid hormone (PTH) analogs, including Forteo. Patients should discontinue Forteo and seek medical attention if they experience signs of an allergic reaction, such as facial swelling, rapid heartbeat, breathing problems, itching, rash, hives, fainting, dizziness, or lightheadedness. Forteo should not be used by anyone who has previously had a severe allergic reaction to teriparatide or to any of the inactive ingredients in the medication.
FDA Safety Announcement: Forteo FDA Safety Label Change and Revised Drug Label
The revised drug label contains a complete list of FDA-approved indications, side effects, warnings, and more.

Tymlos (abaloparatide) injection, solution

Initial FDA Approval: 2017 
Side Effect Update Date: August 3, 2026 
Medication Description: Treats osteoporosis in people at high risk for bone fractures. This medication is a synthetic version of the parathyroid hormone (PTH), which helps to stimulate the growth of new bone and improve bone strength. 
Updated Side Effects/Safety Information: An updated warning that serious allergic reactions, including anaphylaxis, angioedema (swelling that can affect the face, lips, tongue, or throat), and hives, have been reported in people treated with parathyroid hormone (PTH) analogs, including Tymlos. Patients should discontinue Tymlos and seek medical attention if they experience symptoms of an allergic reaction, such as facial swelling, rapid heartbeat, breathing problems, itching, rash, hives, fainting, dizziness, or lightheadedness. Tymlos should not be used by anyone who has previously had a severe allergic reaction to abaloparatide or any of the inactive ingredients in the medication.
FDA Safety Announcement: Tymlos FDA Safety Label Change and Revised Drug Label
The revised drug label contains a complete list of FDA-approved indications, side effects, warnings, and more.

Teriparatide injection, for subcutaneous use

Initial FDA Approval: 1987 
Side Effect Update Date: August 3, 2026 
Medication Description: Treats osteoporosis in people at high risk for bone fractures. This medication is a synthetic version of the parathyroid hormone (PTH), which helps to stimulate the growth of new bone and improve bone strength. 
Updated Side Effects/Safety Information: An updated warning that serious allergic reactions, including anaphylaxis, angioedema (swelling that can affect the face, lips, tongue, or throat), and hives, have been reported in people treated with parathyroid hormone (PTH) analogs, including Teriparatide. Patients experiencing symptoms of an allergic reaction, such as facial swelling, rapid heartbeat, breathing problems, itching, rash, hives, fainting, or dizziness, should stop taking the medication and seek medical help right away. Teriparatide should not be used by anyone who has previously had a severe allergic reaction to it or to any of the inactive ingredients in the medication.
FDA Safety Announcement: Teriparatide FDA Safety Label Change and Revised Drug Label
The revised drug label contains a complete list of FDA-approved indications, side effects, warnings, and more.

Yorvipath (palopegteriparatide) injection, for subcutaneous use

Initial FDA Approval: 2024
Side Effect Update Date: August 3, 2026 
Medication Description: Treats hypoparathyroidism (hypopara), a condition in which the body has low levels of parathyroid hormone (PTH), often due to damage to the parathyroid glands from autoimmune disease or surgery. Hypoparathyroidism can lead to low calcium levels and high phosphorus levels. Yorvipath helps regulate calcium levels by replacing the missing PTH activity.
Updated Side Effects/Safety Information: An updated warning that serious allergic reactions, including anaphylaxis, angioedema (swelling that can affect the face, lips, tongue, or throat), and hives, have been reported in people treated with parathyroid hormone (PTH) analogs, including Yorvipath. Patients experiencing symptoms of an allergic reaction, such as facial swelling, fast heartbeat, breathing problems, itching, rash, hives, fainting, or feeling dizzy or lightheaded, should stop taking the medication and get medical help right away. Yorvipath should not be used by anyone who has previously had a severe allergic reaction to palopegteriparatide or any of the inactive ingredients in the medication.
Essential Extras: Yorvipath is the only FDA-approved treatment for the rare condition of hypoparathyroidism.
FDA Safety Announcement: Yorvipath FDA Safety Label Change and Revised Drug Label
The revised drug label contains a complete list of FDA-approved indications, side effects, warnings, and more.