Tymlos Side Effects: What to Expect and When to Call Your Doctor

Tymlos (abaloparatide) is a highly effective medication for building bone mass and reducing fracture risk in people with osteoporosis — but like any prescription drug, it comes with potential side effects. Understanding what to expect can help you feel confident in your treatment and know when to reach out to your doctor.

This guide covers common and serious side effects of Tymlos, what the clinical trials showed, and clear guidance on when symptoms require a call to your healthcare provider.

Common Side Effects of Tymlos

The following side effects were reported in the ACTIVE Phase 3 clinical trial (18 months in postmenopausal women) and post-marketing experience. Most are mild to moderate in severity:

Hypercalciuria (elevated calcium in urine): The most commonly reported lab abnormality. Usually asymptomatic, but your doctor may monitor urine calcium.

Dizziness: Most common in the first few doses. Often related to orthostatic hypotension (see below). Usually resolves within hours.

Nausea: Mild nausea is common, especially after the first few doses. Taking your injection in the morning with food may help.

Palpitations: A noticeable heartbeat — sometimes rapid or irregular — can occur, typically within hours of injection. Usually short-lived.

Headache: Mild headache was reported in clinical trials. Typically manageable with OTC pain relievers (check with your doctor first).

Back pain: Musculoskeletal pain, including back pain, was reported. Often difficult to distinguish from underlying osteoporosis pain.

Joint pain (arthralgia): Mild to moderate joint aches were reported in clinical trial participants.

High blood pressure (hypertension): Blood pressure elevation was noted in some trial participants. Your doctor may monitor your blood pressure.

Injection site reactions: Redness, bruising, or mild pain at the injection site are normal. Rotate injection sites within the periumbilical area.

Upper respiratory tract infection: Cold-like symptoms were reported by some participants. May or may not be related to Tymlos.

Orthostatic Hypotension: What It Is and How to Handle It

One of the most important side effects to be aware of is orthostatic hypotension — a sudden drop in blood pressure when you stand up from sitting or lying down. With Tymlos, this typically occurs within 4 hours of injection and may cause dizziness, lightheadedness, palpitations, tachycardia (fast heart rate), or nausea.

How to manage it:

For the first few doses, inject when sitting or lying down, then remain seated for several minutes before standing

Don't inject right before activities that require standing or balance

If you feel lightheaded, sit or lie down immediately until symptoms resolve

Many patients find this effect diminishes after the first week of use

Serious Side Effects: When to Call Your Doctor

The following serious side effects require prompt medical attention:

Hypercalcemia (high blood calcium): Symptoms include nausea, vomiting, constipation, muscle weakness, excessive thirst, frequent urination, or confusion. Call your doctor if you experience these symptoms.

Kidney stones (urolithiasis): Tymlos can increase urinary calcium excretion. Symptoms of kidney stones include severe flank pain, bloody urine, nausea, and vomiting. Seek care promptly.

Severe allergic reaction (anaphylaxis): Rare but serious. Symptoms include severe rash, hives, difficulty breathing, chest tightness, or swelling of the face and throat. Call 911 immediately.

Persistent localized bone pain or new soft tissue mass: While osteosarcoma has not been confirmed in humans taking Tymlos, animal studies showed increased risk at high doses. Any new, persistent localized bone pain or a palpable soft tissue mass should be evaluated by your doctor.

Is Tymlos Safe? The Osteosarcoma Question

You may have heard that drugs like Tymlos carry a risk of bone cancer (osteosarcoma). Here's what the science actually says: In animal studies (rats given very high doses for 2 years), abaloparatide caused osteosarcoma. However, in observational studies in humans, no increased rate of osteosarcoma has been found among patients treated with Tymlos or the related drug teriparatide. As of 2025, the FDA updated the Tymlos label to remove the boxed warning for osteosarcoma while retaining it as a precautionary note.

To minimize any theoretical risk, Tymlos is limited to a maximum of 2 years of lifetime use, and it should not be used in patients with certain risk factors for osteosarcoma (open epiphyses, Paget's disease, bone metastases, or prior skeletal radiation).

Managing Tymlos Side Effects: Practical Tips

Inject at the same time each day to help predict when effects may occur

Stay well hydrated — this helps reduce hypercalciuria and kidney stone risk

Eat a balanced diet with adequate calcium and vitamin D as advised by your doctor

Keep all scheduled lab appointments so your doctor can monitor calcium and kidney function

For more information on medications that can interact with Tymlos, see our guide on Tymlos drug interactions.

If you need help finding a pharmacy with Tymlos in stock, medfinder can help locate your nearest specialty pharmacy with availability.