Forteo20 mcg/80 mcl

Forteo is indicated for the treatment of osteoporosis in specific high-risk patient groups where the goal is to increase bone mass and reduce fracture risk.

Established / FDA-Approved Uses

• Treatment of osteoporosis in postmenopausal women at high risk of fracture, including those with a history of osteoporotic fracture, multiple risk factors for fracture, or who have failed or are intolerant to other osteoporosis therapies.
• To increase bone mass in men with primary or hypogonadal osteoporosis at high risk of fracture.
• Treatment of men and women with glucocorticoid-induced osteoporosis at high risk of fracture who are receiving sustained systemic glucocorticoid therapy.

Forteo is an anabolic (bone-forming) agent and is generally reserved for patients with severe osteoporosis or those who have not responded adequately to antiresorptive therapy, based on specialist assessment.

Each pre-filled pen/cartridge contains Teriparatide (recombinant human parathyroid hormone, amino acid sequence 1-34) as the active ingredient, formulated as a sterile, clear, colorless solution for subcutaneous injection, along with excipients such as glacial acetic acid, sodium acetate, mannitol, metacresol (as a preservative), and water for injection.

Forteo is a recombinant form of human parathyroid hormone consisting of the biologically active 1-34 amino acid fragment. It is a bone-forming (anabolic) agent used for the treatment of osteoporosis, in contrast to antiresorptive agents (such as bisphosphonates) that work primarily by slowing bone breakdown. Forteo is administered as a once-daily subcutaneous injection using a pre-filled pen device, typically for a limited treatment duration.

Forteo belongs to the class of parathyroid hormone analogs, classified as an anabolic (bone-forming) agent used in the management of osteoporosis. It is distinct from antiresorptive drug classes such as bisphosphonates, selective estrogen receptor modulators (SERMs), and RANKL inhibitors.

Teriparatide is identical to the N-terminal 34-amino-acid fragment of endogenous human parathyroid hormone (PTH), which is the portion responsible for its biological activity.

Mechanism

Endogenous PTH, when secreted continuously (as in hyperparathyroidism), promotes bone resorption. When Teriparatide is administered once daily by injection, it produces an intermittent, pulsatile exposure that preferentially stimulates osteoblast (bone-forming cell) activity over osteoclast activity. This results in a net increase in bone formation, improved bone microarchitecture, and increased bone mineral density, particularly at the lumbar spine and femoral neck.

Pharmacokinetics

After subcutaneous injection, Teriparatide is rapidly absorbed, reaching peak plasma concentration within approximately 30 minutes, with an elimination half-life of about 1 hour. It is cleared by hepatic and peripheral metabolism, with renal excretion of metabolites.

Inject Forteo subcutaneously into the thigh or abdominal wall once daily, at approximately the same time each day, using the pre-filled pen. Administer the first few doses in a setting where the patient can sit or lie down promptly if symptoms of dizziness or lightheadedness occur. Do not inject into a vein or muscle. Each pen should be used by only one patient.

Digoxin

Forteo causes transient increases in serum calcium, which may theoretically potentiate the effects of digoxin; caution is advised in patients taking digoxin.

Loop Diuretics (e.g., Furosemide)

Concomitant use of loop diuretics may increase the risk of hypercalcemia when combined with Forteo.

Antiresorptive Agents

Concurrent use of Forteo with bisphosphonates is generally not recommended, as it may attenuate the bone-forming effect of Forteo.

Common side effects associated with Forteo include:

• Nausea
• Leg cramps
• Dizziness
• Headache
• Injection site pain, redness, or irritation
• Arthralgia (joint pain)
• Mild, transient elevations in serum calcium

Less common but clinically important effects include transient orthostatic hypotension shortly after dosing (see Precautions) and hypercalcemia. Seek prompt medical attention for signs of a severe allergic reaction (rash, swelling of the face or throat, severe dizziness, difficulty breathing).

Forteo is not indicated for use in women of childbearing potential, and there is limited data on its use during pregnancy or breastfeeding, since the approved population (postmenopausal women, men, and glucocorticoid-induced osteoporosis patients) does not typically include women who are or may become pregnant. If exposure occurs during pregnancy or lactation, Forteo should be used only if clearly needed and the potential benefit justifies the potential risk to the fetus or infant; a physician should be consulted before use in any such situation.

Forteo products have historically carried a boxed warning regarding a dose- and duration-dependent increase in osteosarcoma (a type of bone cancer) observed in rodent studies at systemic exposures relevantly higher than in humans; this signal has not been confirmed in extensive human post-marketing surveillance, and current labeling in many markets has updated this warning language accordingly, though precautionary measures are still followed.

• Duration of treatment: Total lifetime exposure to Forteo, whether from a single course or cumulative across multiple courses, should not exceed the maximum duration specified in the product labeling (see Duration of Treatment).
• Orthostatic hypotension: Transient episodes of orthostatic hypotension and dizziness can occur within a few hours of injection, particularly with the first few doses. Administer initial doses where the patient can sit or lie down if symptoms occur.
• Hypercalcemia: Mild, transient increases in serum calcium are common; monitor calcium levels if clinically indicated, especially in patients with risk factors.
• Injection site reactions and active or recent urolithiasis (kidney stones) warrant caution.
• Following completion of a Forteo treatment course, transitioning to an antiresorptive agent is often recommended, per specialist guidance, to help maintain the bone density gains achieved.

Overdose of Forteo may result in hypercalcemia, nausea, vomiting, hypotension, and dizziness. There is no specific antidote. If overdose is suspected, seek immediate medical attention or contact a poison control center. Management is supportive, guided by the treating physician, and may include monitoring of serum calcium and symptomatic treatment as appropriate.

Store Forteo pens in a refrigerator (2°C to 8°C) at all times, including during use. Do not freeze. Always recap the pen after each use and keep it away from light. Discard the pen 28 days after first use, even if some solution remains. Keep out of reach of children.

Renal Impairment

Use with caution in mild to moderate renal impairment; not recommended in severe renal impairment due to limited safety data.

Hepatic Impairment

Limited data available; use Forteo with caution.

Elderly

No overall differences in safety or efficacy have been observed in elderly patients compared to younger adults; no dose adjustment is required based on age alone.

Pediatric Patients

Forteo is contraindicated in pediatric patients and young adults with open epiphyses due to the theoretical risk of osteosarcoma (see Contraindications and Pediatric Uses).

The maximum recommended lifetime duration of treatment with Forteo is limited per product labeling (commonly up to 24 months, cumulative across any courses of treatment), based on precautionary limits established due to the osteosarcoma signal observed in animal studies. Patients should not exceed this maximum cumulative exposure. The specific maximum duration should be confirmed with the prescribing physician based on the current approved labeling.

Parathyroid hormone analog; anabolic (bone-forming) agent; osteoporosis therapy.

Teriparatide, given as a once-daily intermittent subcutaneous dose, binds to PTH receptors on osteoblasts, stimulating new bone formation on both trabecular and cortical bone surfaces. This anabolic action increases bone mineral density and improves bone microarchitecture, which is believed to translate into reduced fracture risk, in contrast to the continuous PTH exposure seen in hyperparathyroidism, which favors bone resorption.

C

The safety and efficacy of Forteo have not been established in pediatric patients. Forteo is contraindicated in children and young adults with open epiphyses (open growth plates) due to a theoretical risk of osteosarcoma observed in animal studies, and should not be used in this population outside of specialist-directed care where benefit-risk has been individually assessed for a rare, specific indication.