Bitiron

Bitiron Uses, Dosage, Side Effects, Food Interaction and all others data.

Bitiron is a synthetically derived thyroid hormone replacement preparation. It consists of levothyroxine sodium (thyroxine, T4) and liothyronine sodium (triiodothyronine, T3) in a 4 to 1 ratio by weight. Bitiron was developed when it was believed that serum levels of both T4 and T3 were maintained by direct thyroidal secretion. It is now known that the thyroid gland secretes approximately ten times more T4 than T3 and that 80% of serum T3 is derived from deiodination of T4 in peripheral tissues. Administration of levothyroxine alone is sufficient for maintaining serum T4 and T3 levels in most patients and combination hormone replacement therapy generally offers no therapeutic advantage. In fact, administration of T3 may result in supratherapeutic levels of T3.

Thyroid hormone drugs are natural or synthetic preparations containing T4 or T3 or both. T4 and T3 are produced in the human thyroid gland by the iodination and coupling of the amino acid tyrosine. Bitiron is a synthetic preparation of T4 and T3 in a 4:1 weight-based ratio. These hormones enhance oxygen consumption by most tissues of the body and increase the basal metabolic rate and the metabolism of carbohydrates, lipids and proteins. Thus, they exert a profound influence on every organ system in the body and are of particular importance in the development of the central nervous system.

Bitiron
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Bitiron
Availability	Discontinued
Generic	Liotrix
Liotrix Other Names	Levothyroxine Sodium mixture with Liothyronine Sodium, Liotrix, Liotrix (T4;T3)
Related Drugs	levothyroxine, Synthroid, Armour Thyroid, Euthyrox, liothyronine, Tirosint
Type
Formula	C₃₀H₂₁I₇N₂Na₂O₈
Weight	Average: 1471.8072 Monoisotopic: 1471.440608948
Groups	Approved
Therapeutic Class
Manufacturer
Available Country
Last Updated:	September 19, 2023 at 7:00 am

Uses

May be used to treat primary, secondary or tertiary hypothyroidism. May also be used to suppress thyroid stimulating hormone (TSH) secretion in patients with simple (nontoxic) goiter, subacute or chronic lymphocytic thyroiditis multinodular goiter, and in the management of thyroid cancer. May be used in conjunction with other antithyroid agents to treat thyrotoxicosis to prevent goitrogenesis and hypothyroidism. May also be used for differential diagnosis of suspected mild hyperthyroidism or thyroid gland autonomy.

How Bitiron works

The hormones, T₄ and T₃, are tyrosine-based hormones produced by the thyroid gland. Iodine is an important component in their synthesis. The major secreted form of thyroid hormone is T4. T4 is converted T3, the more active thyroid hormone, by deiodinases in peripheral tissues. T3 acts in the body to increase basal metabolic rate, alter protein synthesis and increase the body's sensitivity to catecholamines (such as adrenaline). Thyroid hormones are essential for proper development and differentiation of all cells of the human body. T₄ and T₃ regulate protein, fat and carbohydrate metabolism to varying extents. The most pronounced effect of the hormones is in altering how human cells use energetic compounds. The thyroid hormone derivatives bind to the thyroid hormone receptors initially to initiate their downstream effects.

Toxicity

Hypermetabolic state indistinguishable from thyrotoxicosis of endogenous origin. Symptoms of thyrotoxicosis include weight loss, increased appetite, palpitations, nervousness, diarrhea, abdominal cramps, sweating, tachycardia, increased pulse and blood pressure, cardiac arrhythmias, tremors, insomnia, heat intolerance, fever, and menstrual irregularities.

Food Interaction

Avoid calcium supplements/calcium rich foods. Calcium may interfere with the absorption of this drug by forming an insoluble complex. Separate medication administration by at least 4 hours.
Avoid grapefruit products. Grapefruit may delay the absorption of this medicaiton.
Avoid high-fiber foods. High-fiber foods may affect absorption. Separate medication administration by at least 1 hour.
Avoid iron supplements. Iron may interfere with the absorption of this drug by forming an insoluble complex. Separate medication administration by at least 4 hours.
Avoid multivalent ions. Avoid iron and calcium containing products as well as antacids.
Take before a meal. Take 30-60 minutes before breakfast.
Take on an empty stomach.

[Moderate] ADJUST DOSING INTERVAL: Consumption of certain foods as well as the timing of meals relative to dosing may affect the absorption of T4 thyroid hormone (i.e., levothyroxine).

T4 absorption is increased by fasting and decreased by foods such as soybean flour (e.g., infant formula), cotton seed meal, walnuts, dietary fiber, calcium, and calcium fortified juices.

MANAGEMENT: Preparations containing T4 thyroid hormone should be administered on a consistent schedule with regard to time of day and relation to meals so as to avoid large fluctuations in serum levels.

Foods that may affect T4 absorption should be avoided within several hours of dosing if possible.

When administered to patients receiving continuous enteral nutrition for more than 7 days, some experts recommend that the tube feeding should be interrupted for at least 1 hour before and 1 hour after the dose of levothyroxine is given and to monitor patients' thyroid function.

Bitiron Hypertension interaction

[Major] Thyroid hormones cause increases in myocardial contractility and heart rate as a result of increased metabolic demands and oxygen consumption.

Therapy with thyroid hormones should be administered cautiously and initiated at reduced dosages in patients with cardiovascular disorders such as angina, coronary artery disease, and hypertension.

Clinical monitoring of cardiovascular function is recommended.

If chest pain or exacerbation of cardiovascular disease occurs, the dosage of thyroid hormone should be reduced, even at the expense of achieving euthyroid state.

Thyroid hormones should not be administered to patients with an acute myocardial infarction that is not complicated by hypothyroidism.

Bitiron multivitamins interaction

[Moderate] ADJUST DOSING INTERVAL: Concurrent administration of calcium-containing products may decrease the oral bioavailability of levothyroxine by one-third in some patients.

Pharmacologic effects of levothyroxine may be reduced.

The exact mechanism of interaction is unknown but may involve nonspecific adsorption of levothyroxine to calcium at acidic pH levels, resulting in an insoluble complex that is poorly absorbed from the gastrointestinal tract.

In one study, 20 patients with hypothyroidism who were taking a stable long-term regimen of levothyroxine demonstrated modest but significant decreases in mean free and total thyroxine (T4) levels as well as a corresponding increase in mean thyrotropin (thyroid-stimulating hormone, or TSH) level following the addition of calcium carbonate (1200 mg

Four patients had serum TSH levels that were higher than the normal range.

Both T4 and TSH levels returned to near-baseline 2 months after discontinuation of calcium, which further supported the likelihood of an interaction.

In addition, there have been case reports suggesting decreased efficacy of levothyroxine during calcium coadministration.

It is not known whether this interaction occurs with other thyroid hormone preparations.

Some experts recommend separating the times of administration of levothyroxine and calcium-containing preparations by at least 4 hours.

Monitoring of serum TSH levels is recommended.

Patients with gastrointestinal or malabsorption disorders may be at a greater risk of developing clinical or subclinical hypothyroidism due to this interaction.