Protirelin (intravenous)

Protirelin used to be used to measure how the anterior pituitary gland functioned in patients with thyroid problems.

Overview

Protirelin is a now-discontinued diagnostic compound used to measure the responsiveness of the anterior pituitary gland by stimulating the release of a hormone called thyroid-stimulating hormone, or TSH, from the anterior pituitary gland. This hormone then stimulates the thyroid gland. By measuring pre and post-administration levels of TSH in the patient’s blood, the function of the anterior pituitary gland can be measured.

This measurement is done by taking a sample of blood, then having the drug administered via intravenous injection by a healthcare professional. After a short time, usually about 15 to 30 minutes, or enough time for the drug to prompt activity in the anterior pituitary gland, more blood samples are taken, and the results of the blood analysis allow conclusions to be drawn to determine the function of the anterior pituitary gland; the level of thyroid stimulating hormone in the blood gives an indication of how well the anterior pituitary is working.

Protirelin is not a prescription medication and, as such, cannot be obtained over the counter or from a doctor. The administration of Protirelin is to be done by a qualified healthcare professional at the time of analysis.

Conditions treated

  • Diagnosis of thyroid and pituitary gland function

Type of medicine

  • Diagnostic aid (hormone stimulator)

Side effects

Due to the nature of the drug and its action in stimulating gland and hormone production, unwanted side effects may occur. Though some minor side effects may occur and usually present themselves soon after administration, it may be important to seek medical attention following treatment.

Most side effects of Protirelin are minor in nature and, should these symptoms present themselves, the patient should discuss them with the doctor who is administering the injection. As this drug is only to be administered by a qualified healthcare professional, monitoring of the patient should take place before, during and after administration, and medical staff should be present in the event that any unwanted side effects need to be discussed.

Most commonly, Protirelin may cause feelings of lightheadedness, upset of or pain in the stomach and nausea. Protirelin has also been reported to cause an unpleasant taste and or dryness in the mouth. Headaches, sometimes reported as severe, have also been reported, alongside a need to urinate frequently, and flushing or redness of the skin both locally around the injection site, and generally.

Other side effects that, while reported less frequently, should be mentioned, include sensations of anxiety, increased sweating beyond normal, a tingling sensation in the extremities, drowsiness, and the feeling of tightness or pressure in the throat. Should these occur, medical staff should be notified as soon as possible.

Though it is reported very rarely, some patients have experienced the serious side effect of fainting. However, as this drug is administered by a healthcare professional with the patient lying down, the risk of danger from any side effects is minimized as long as the correct procedure is followed, and any further concerns can be raised with the practicing physician. It is important that the patient remains lying down for 15 to 30 minutes after administration to ensure the likelihood of fainting is reduced.

Protirelin is generally administered because the utility of this diagnostic tool is greater than the risk of experiencing side effects.

Dosage

The dosage of Protirelin is determined through analytical methods by the practicing physician and may vary from person to person. As the dosage required will change from patient to patient, it’s important that the patient follows all the instructions that they are given by their own doctor.

When determining the dosage for the patient, the healthcare professional will consider various factors, for example, the condition or symptoms that necessitated the use of Protirelin in the first place. General dosage instructions have been provided by the manufacturers of Protirelin, but adjustments to the dosages can be made by the administering physician. When establishing the size of the dose, factors discussed between the patient and administering physician will provide the required insight necessary to determine correct dosage size.

For the purpose of running the diagnostic test to determine gland function, the manufacturers of Protirelin suggest that the recommended dosage for adults is 500 micrograms (mcg) injected into a vein, with the patient lying horizontally for 15 to 30 minutes.

Recommended dosage sizes for children are not provided. The dosage size for children will vary by age, weight and other factors, and the correct dosage should be determined by the administrating physician.

If the patient experiences signs of an overdose (changes in vision, blindness, pain in the chest, double vision, dizziness, fainting, lightheadedness, rapid or irregular heartbeat, extreme tiredness or coma), they will need immediate attention and should notify the doctor immediately.

Interactions

Drugs interact with other drugs in the human body, altering the effect, efficacy and duration of each medication. This may cause one medication to be ineffective during treatment or diagnosis, or it may cause dangerous reactions in the patient. For these reasons, it's important for patients to keep an updated list of all drugs they are presently taking, including the frequency and dosage of each drug they take.

Where some patients fail is in assuming that this applies only to prescribed medication. On the contrary, it's important that your doctor knows everything you're taking, including non-prescription, over the counter and illicit drugs.

Below is a short list of the major drugs known to have negatively interacted with Protirelin. It is by no means comprehensive and only indicative. If the patient is already taking any of these medications, Protirelin should not be prescribed and the doctor may need to select alternative diagnosis options.

  • Cyproheptadine
  • Thioridazine

If any other medications are being taken by the patient, it is important that they discuss what these are with their doctor. There are many medications that, when taken alongside Protirelin, can cause negative interactions and result in serious or dangerous side effects. Clear, open discussion with your doctor is an important part of any treatment regime using Protirelin.

Warnings

During the consultation, the patient should disclose any present or historical health problems to their doctor, and also notify them if they experience any known allergies.

The patient should notify their administering physician of a history of any of the conditions mentioned below, as they may affect the safety of the patient, and hence their ability to take Protirelin:

  • Poor heart health, including heart or blood vessel disease, heart attack, angina, heart failure, or an irregular heartbeat
  • High or low blood pressure
  • Any history of strokes – Protirelin may cause sudden changes in blood pressure and put patients at increased risk
  • Kidney disease

As this medication can make cause feelings of drowsiness, lightheadedness, and dizziness, it is suggested that, following treatment, the patient does not undertake any strenuous exercise, operate an automobile or undertake any activity that requires an alert mind and clear vision. Patients should also practice caution when drinking alcohol after taking Protirelin.

Other side effects that have not been listed might occur in some patients. Should any other unwanted side effects present themselves, the patient should discuss with their healthcare professional.

Storage

As Protirelin is a hormone stimulating drug kept in solution form, it should be stored at room temperature. Freezing Protirelin should be avoided, as it will destroy the active compound in solution. Additionally, manufacturers of Protirelin recommend that it be kept away from moisture, heat and direct light.

Once the doctor and patient determine the drug is not required for treatment any longer, the remaining supply can be properly disposed of; expired medication or medication that is no longer in use should be disposed of in an appropriate manner. Healthcare professionals can advise patients on how best to get rid of the remaining supply, but as Protirelin is only to be administered by a healthcare professional, this should not be a concern for the patient.

Summary

While Protirelin has demonstrable use as a diagnostic tool, it can also pose a risk to patients who do not communicate openly with their healthcare professionals. As a diagnostic tool, Protirelin has use in measuring the function and activity of the anterior pituitary gland and thyroid gland in the human body, but it also affects the way that the body responds to different stimuli.

As this medication has potential to induce side effects of drowsiness, dizziness, and sleepiness, the drug can impair a patient's function on a day to day basis, and cause danger if precautions are not made. For this reason, it's important for the patient to discuss with their healthcare professional all that is known about their medical history, including their family members' medical history where relevant.

There are many medications that may cause adverse reactions when combined with Protirelin and several conditions that may be made worse by use of the drug. For this reason, it is in the best interest of the patient to talk openly with their healthcare professional. While side effects can occur, when administered correctly, Protirelin can be a useful method to determine thyroid and pituitary gland function.

 

Resources
Last Reviewed:
January 31, 2018
Last Updated:
January 27, 2018
Content Source: