Teriparatide

Osteoporosis causes bone weakness in a portion of the elderly population, with more women affected than men. The anabolic agent teriparatide can help to substitute for the parathyroid hormone in order to help strengthen and grow bones so that bone weakness is not as prevalent.

Overview

The global pharmaceutical company Eli Lilly and Company offers teriparatide under the brand name Forteo, and it basically amounts to a recombinant DNA form of the parathormone that is produced naturally in the human body in order to increase bone strength and mass. Eli Lilly is already one of the upper echelon pharmaceutical companies delivering their products to around 125 countries with offices in 18 countries worldwide. It can be taken intermittently, and its structure resembles a portion of the PTH (the bioactive segment) so that osteoblasts are activated more than the opposing osteoclasts, and bone increases accordingly. This process is based on the body's natural ability to resorb and then rebuild the bone tissue within.

The United States Food and Drug Administration (FDA) approved teriparatide in 2002, and in doing so it was indicated for use with osteoporosis in post-menopausal women if they were at a high risk for a bone fracture or already had a history of a fracture related to osteoporosis. It is also generally given to clients who have multiple risk factors that could easily lead to broken bones or those whose bodies did not respond well to other forms of treatment for the disease. Some of the most common bones that break without preventive treatment can be the spinal vertebrae, hip bones, or bones in the forearm. With teriparatide, the patient can see an increase in bone density that usually amounts to about an 8% improvement (in the spine) after one year of treatment.

The anabolic agent can also be used in an off-label manner in order to help fracture repair by speeding up the process, and it is also a good solution for fracture nonunions that might otherwise be troublesome in a patient. The clinical trials that have been coordinated in order to determine the efficacy of teriparatide did show that there was a marked improvement over placebo in the percentage that experienced new fractures, and this was especially true in regards to the vertebrae. Some of the best-known cases have occurred when the teriparatide treatment was given to athletes so that they could recover from an injury in time to be able to participate in some of the larger events such as the World Cup or the Super Bowl (Francesco Totti and Terrell Owens).

Treated Conditions

  • Osteoporosis
  • Bone fracture recovery and nonunions

Type of Medicine

  • Subcutaneous injection to thigh or abdomen

Side Effects

Osteosarcoma, a cancerous bone tumor, is one of the potential side effects that might manifest and be associated with teriparatide treatment, but the possibility has only been theoretically surmised based on rat studies, and there have not been any confirmed human cases of this yet. Some of the more common side effects that might occur in a mild to moderate form include leg cramps, joint pain, muscle cramps, cough, sore throat, headache, constipation, nausea, diarrhea, and reactions at the injection site. In rarer instances, there may be some more serious adverse effects such as tiredness, mental confusion or mood changes, and fainting. It is important to discuss any of these with the prescribing physician if they do occur, so that the proper actions can be taken.

Dosage

An adult dose is usually equivalent to 20 micrograms (mcg), and this is given via the subcutaneous injection route either into the abdominal wall or into the patient's thigh area. Dosing in children is usually a lesser amount, and the figure should be determined by the doctor in order to achieve the desired results. There are a couple of different levels of the drug that can be found in the injectable pens, and these are 600 mcg/2.4 mL and 750 mcg/3 mL.

Drug Interactions

The most well-known drug interaction that can occur with teriparatide is digoxin, and those who are already on this medication for help with their heartbeat may need a dose adjustment in order to properly endure. Some of the brand names that this drug is known by include Digitek, Lanoxicaps, Lanoxin. Also, since this is derived from the leaves of a digitalis plant, there is a possibility of similar interactions should a person be taking this in some herbal form. It is vital to discuss any current medications with the attending physician so that any necessary adjustments can be made during the teriparatide treatment.

Warnings

This drug is formulated for a subcutaneous injection and should never be injected into a muscle or vein as this could lead to medical issues. Anyone who has a known allergy to teriparatide or any of the inactive ingredients that may be in the drug should discuss this with a doctor before undergoing treatment with the drug. An overactive parathyroid gland (this can be measured in the blood through several forms such as intact PTH, N-terminal PTH, mid-molecule PTH, and C-terminal PTH) or high calcium levels are also contraindicated in anyone using teriparatide. Also, existing bone problems besides osteoporosis may make the use of teriparatide inappropriate depending on the situation. Those who have an increased risk of the bone cancer known as osteosarcoma should not be given the drug due to the potential of that manifesting as it has in rat studies. This type of increased risk that is contraindicated can be found in those with Paget's disease of the bone, open epiphysis, radiation therapy involving the skeleton, or serum alkaline phosphate levels that are elevated unexplainably. In rat studies, the chance of bone cancer increased in accordance with higher dosage levels, and so it should be considered carefully in regards to the potential benefits if someone has some of these potential exacerbating conditions. It is also important that those with renal (kidney) impairment are monitored appropriately since the half-life of the teriparatide has been shown to increase in that population of patients as well as the AUC.

The Center for Disease Control (CDC) has given multiple warnings in regards to the multiple-dose injection pens, and they should not be used to administer the drug to more than one person. Even if the needle is changed there is still a high risk of infection that would not otherwise be relevant. For this reason, the pen is almost always clearly labeled by the distributing pharmacy or company so that there is a reduced chance of mixing these up if there are multiple people in the same residence who are using teriparatide to help with their osteoporosis health condition.

It is not recommended that the recombinant DNA form of the PTH hormone (teriparatide) be used for a period of more than two years due to the complications that can occur with such chronic exposure. It is not something that should be utilized in pregnant or pre-menopausal women due to the fact that adverse events in pregnant animals have been observed, and a complete and thorough study on the pregnant human population has not been conducted as yet. Patients should be warned and advised of the potential adverse effects so that they will recognize them and be able to alert a medical professional.

Storage

The medication should always be refrigerated, but it should not be frozen. Teriparatide usually comes in the form of a pen, and it is important that this is not kept for more than 28 days at a time, even if there is still some of the drug left inside. The pen should be discarded and a replacement taken.

Summary

Teriparatide represents amino acid sequence number 1 through 34 of the parathyroid hormone (PTH) in humans. Because of this, it can be used to help those who are primarily elderly with osteoporosis. This includes osteoporosis in men and osteoporosis in post-menopausal women where it is effective due to an anabolic effect that helps with bone growth. It can also be utilized in an off-label method so that its functionality can help bones to regrow faster than normal. This can be quite beneficial in athletes, and other industries, where it is necessary to recover as quickly as possible in order to be ready for important events or work.

The mechanism of action is generally seen in regards to its ability to activate osteoblasts at a rate that surpasses osteoclasts and leads to improved bone growth rates. Eli Lilly and Company are the manufacturers of the brand name version of the drug that is known as Forteo. It usually comes in an injection pen that can be used to administer the drug in either the thigh or abdominal wall. A PTH level that is elevated chronically can lead to a depletion of the bones, but if it is administered once per day for a time this can lead to a net effect that results in new bone formation and a better density than would be achieved through normal body processes without the introduction of the hormone. This is why the FDA has had the drug approved since 2002 so that it can help those who do not respond to other types of osteoporosis treatments.

Osteoporosis can be a devastating disease that has a myriad of causes. Sometimes it can be prevented through things like a proper diet in the earlier years of life and avoiding alcoholism, anorexia, and a number of other avoidable factors. It has been proven through various medical studies that drinking alcohol and smoking tobacco can lead to this condition in the later years of life, and so it is important that there are drugs like teriparatide that can assume the role of the parathyroid hormone in order to help reestablish the balance necessary for longevity and healthy bones. If a person with these risk factors and a noticeable diagnosis of osteoporosis is not put on such a medication, then this can often lead to disabilities and even death in many cases, especially in the lesser developed countries. One of the reasons that the disease can end up being so tough on those inflicted is because of the fact that there are generally no symptoms that will allow a diagnosis to be given until a person ends up breaking a bone in a fashion that seems too easy for the normal population. In these instances, bone mineral density (BMD) measurement and conventional radiography are some of the foremost ways that the condition can be determined, and then a treatment regimen that might include teriparatide can be followed as appropriate.

Resources
Last Reviewed:
December 22, 2017
Last Updated:
December 22, 2017
Content Source: