Pronunciation: for-TAY-o
Generic name: teriparatide
Dosage form: injection
Drug class: Parathyroid hormone and analogs

Medically reviewed by Melisa Puckey, BPharm. Last updated on Apr 7, 2025.

What is Forteo?

Forteo injection is a prescription medicine used to treat osteoporosis in specific men and postmenopausal women who are at high risk for bone fracture and are unable to use other treatments for osteoporosis. Forteo injections help to stimulate the natural bone-rebuilding process to increase bone mineral density and bone strength, which may prevent fractures. 

Forteo is a man-made form of parathyroid hormone that exists naturally in the body and is involved in bone remodeling. Forteo injection works (mechanism of action) by acting on specific receptors (PTH1 receptor) this increases the activity and number of osteoblasts (cells that lay down new bone), which increases bone mass (bone mineral density). 

Forteo injection is given once a day under the skin (subcutaneous injection) in your thigh or abdomen, using a prefilled pen. Forteo is available as an easy-to-use delivery device that can be self-administered. Each pen contains 28 doses. 

Forteo generic name is teriparatide.

Who can use Forteo?

Tymlos FDA approval is for the treatment of: 

• Postmenopausal women who have osteoporosis, who are at high risk for having broken bones (fractures), or who cannot use other treatments for osteoporosis. Forteo helps to decrease the chance of broken bones in the spine and other bones in postmenopausal women who have osteoporosis. 
• Men with primary or hypogonadal osteoporosis who are at high risk for having broken bones, or who cannot use other treatments for osteoporosis. Forteo helps to increase the bone mass in men with primary or hypogonadal osteoporosis.
• Men and women with osteoporosis due to the use of glucocorticoid medicines, such as prednisone, for several months, who are at high risk for having broken bones (fractures) or who cannot use other osteoporosis treatments.

Patients should take calcium and vitamin D supplements if their dietary intake is inadequate.

Using Forteo for more than 2 years during a patient's lifetime should only be considered if a patient remains at or has returned to having a high risk for fracture.

Forteo side effects

Common Forteo side effects

The most common Forteo side effects may include:

• Pain 21.3%
• Joint pain 10.1%
• Runny nose  9.6%
• High blood pressure 8.7%
• Nausea 8.5%
• Dizziness 8.0%
• Headache 7.5%
• Weakness tiredness or lack of energy 7.1%
• Increased cough 6.4%
• Pharyngitis 5.5%
• Constipation 5.4%
• Indigestion 5.2%
• Diarrhea 5.1%

These common side effects occurred in 5% or more of men and women using Forteo in the two principal osteoporosis trials.

Serious Forteo side effects

Get emergency medical help if you have signs of an allergic reaction to Forteo including hives; difficulty breathing, and swelling of your face, lips, tongue, or throat.

Other serious side effects can occur, call your doctor at once if you have:

• bone pain;
• new or unusual swelling or lumps under your skin;
• a light-headed feeling, like you might pass out (may occur within 4 hours after injection);
• pounding heartbeats or fluttering in your chest after using an injection; or
• high calcium levels - confusion, muscle weakness, nausea, vomiting, lack of energy, constipation, increased thirst or urination, weight loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking this medicine

You should not use Forteo if you are allergic to the active ingredient teriparatide or any of the inactive ingredients.

Forteo is not for use in children or young adults whose bones are still growing.

To make sure Forteo is safe for you, tell your doctor if you have ever had:

• Paget's disease or a bone disease other than osteoporosis;
• bone cancer or radiation treatment;
• a genetic condition that increases your risk of bone cancer;
• overactive parathyroid glands;
• high blood levels of calcium;
• a painful skin condition caused by too much calcium;
• kidney failure;
• a kidney stone; or
• an autoimmune disorder such as rheumatoid arthritis, lupus, or psoriasis.

Pregnancy 

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Breastfeeding

It is not known whether Forteo active ingredient teriparatide passes into breast milk or if it could harm a nursing baby. You should not breastfeed while using Forteo.

Warnings

Forteo has caused bone cancer (osteosarcoma) in animals but it is not known whether this would occur in people using this medicine. Talk with your doctor about your own risk.

Tell your doctor if you have conditions such as Paget's disease, high blood levels of calcium or alkaline phosphatase, or a history of bone cancer or radiation treatment involving your bones.

Avoid smoking cigarettes or drinking alcohol. Smoking or heavy drinking can reduce your bone mineral density, making fractures more likely.

How should I use Forteo?

Use Forteo exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Forteo is injected under the skin with an easy-to-use pen. A healthcare provider should teach you how to properly use the medication by yourself.

Forteo is usually given once per day at the same time each day.

Wash your hands before every injection. Prepare the injection site as your healthcare provider instructed.

Forteo injection instructions

Remove the Forteo from the refrigerator

Pull of white cap

Attach a new needle 

• Pull off the paper tab.
• Push the needle straight onto the medicine cartridge and screw the needle on in a clockwise motion.
• Pull off the large needle cover and put the cover aside.

Set dose

• Pull out the black injection button until it stops.
• Check to make sure you can see the red stripe.
• Remove the small needle protector and discard.

Inject dose

• Gently pinch a fold of skin on your abdomen or thigh and insert the needle straight into the skin at a 90-degree angle.
• Use a different place each time you give an injection. Do not inject into the same place two times in a row.
• Push the black button in until it stops.
• Hold the device in place and count to 5 slowly to ensure you receive the correct dose.
• Remove the device from your skin.

Check dose

• Once you complete your injection and remove the needle from your skin take your thumb off the black injection button.
• Check to make sure the black button is completely in.
• You should not see the yellow shaft if it has been administered correctly.

Remove needle

• Replace the needle cover as instructed.
• Unscrew the covered needle by turning it counter-clockwise.
• Remove the needle and discard it into a sharps container.
• Push the white cap back on.

Storage

• Return the Forteo to the refrigerator for storage.

General information

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all the instructions.

Prepare the Forteo injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Use only the injection pen provided with Forteo. Do not transfer the medicine to a syringe or other injection device or you could get an overdose.

Teriparatide can cause you to feel dizzy or light-headed. Always give your injection at a time and place where you can sit or lie down for a short time afterward.

Each prefilled injection pen contains enough teriparatide for 28 separate injections. 

Throw the pen away after 28 injections, even if there is still medicine left inside.

Forteo may be only part of a complete treatment program that also includes diet, exercise, taking vitamin or mineral supplements, and changing certain behaviors. Follow your doctor's instructions very closely.

Store the Forteo injection pen in a refrigerator when not in use. Take the pen out of the refrigerator only long enough to use it. After use, remove the needle, recap the pen, and return it to the refrigerator.

Do not freeze Forteo, and throw away the medicine if it has become frozen.

Forteo dosing information

Usual Adult Forteo Dose for Osteoporosis:

• 20 mcg subcutaneously once a day into the thigh or abdominal wall
• Duration of Therapy: Lifetime use greater than 2 years should only be considered if fracture risk remains high.
• Supplemental calcium and vitamin D should be taken if daily dietary intake is inadequate.

What happens if I miss a dose?

Use the missed dose on the same day you remember it. Use your next dose at the regular time and stay on your once-daily schedule. Do not use 2 doses in one day.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, dizziness, headache, feeling light-headed, or fainting.

What should I avoid while using Forteo?

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Avoid smoking, or try to quit. Smoking can reduce your bone mineral density, making fractures more likely.

Avoid drinking large amounts of alcohol. Heavy drinking can also cause bone loss.

What other drugs will affect Forteo?

Tell your doctor about all your other medicines, especially:

• digoxin, digitalis.
• warfarin (Coumadin, Jantoven); or
• a steroid medicine (such as hydrocortisone, prednisone, methylprednisolone, and others).

This list is not complete. Other drugs may interact with teriparatide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Forteo Package Insert 

HCPs and patients often use the Forteo Package Insert (PI) for more detailed information about this medicine. The  Package Insert (prescribing information) contains more comprehensive information on Indications and Usage, Dosage and Administration, Clinical Pharmacology, Clinical Studies, Drug Interaction, and more. Discuss any medical questions you have with your HCP (health care professional). This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

The Package Insert is sometimes called Forteo Prescribing Information (PI) or FDA label.

Storage

• Store in the refrigerator between 36°F to 46°F (2°C to 8°C) until ready to use.
• Use it right away after you remove it from the refrigerator.
• Do not freeze this injection. Do not it if it has been frozen.
• Throw away the the Forteo delivery device after 28 days after starting to use it, even if it has medicine in it.
• Do not use the injection after the expiration date printed on the delivery device and packaging.
• Recap Forteo and place if refrigerator when not in use to protect it form heat physical damage and light.

Ingredients

Active ingredient: teriparatide

Inactive ingredients: glacial acetic acid, sodium acetate (anhydrous), mannitol, metacresol, and water for injection. In addition, hydrochloric acid solution 10% and/or sodium hydroxide solution 10% may have been added to adjust the product to pH 4.

Company

Forteo Lilly USA, LLC, Indianapolis, IN 46285, USA

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