Emcitate

Emcitate is used to treat peripheral thyrotoxicosis in adults and children with monocarboxylate transporter 8 (MCT8) deficiency, also called Allan-Herndon-Dudley syndrome. It is taken orally or by enteral feeding tube once daily or in two to three divided doses spread throughout the day.

MCT8 deficiency is a rare inherited (X-linked) disorder caused by changes in the SLC16A2 gene. MCT8 is a transporter that normally carries thyroid hormone into certain cells, including brain cells. When MCT8 does not work properly, too little thyroid hormone reaches the brain, while the active thyroid hormone triiodothyronine (T3) builds up in the blood and affects other parts of the body. This excess thyroid hormone outside the brain is called peripheral thyrotoxicosis.

Emcitate can enter cells without needing MCT8. It helps lower the high T3 levels in the blood that cause peripheral thyrotoxicosis. It belongs to the drug class called thyroid hormone receptor agonists, which act like thyroid hormone in the body.

Emcitate (tiratricol) received FDA approval on September 28, 2026, and is the first FDA-approved treatment for patients with MCT8 deficiency in the United States. Emcitate is not recommended for the treatment of primary hypothyroidism (an underactive thyroid gland).

Emcitate lowered and controlled high T3 levels in two clinical studies in males with MCT8 deficiency.

In Study 1, people whose T3 levels were stable on Emcitate were randomly assigned to continue it or switch to placebo for 30 days. T3 levels rose in everyone who switched to placebo but stayed about the same in those who continued Emcitate.

In Study 2, average T3 levels fell to within the normal range after 12 months of Emcitate, and heart rate and systolic blood pressure also decreased.

A dash (-) means Study 2 did not include a placebo group.

Emcitate is approved for use in children. The studies included 55 children aged 10 months to less than 17 years.

Give Emcitate exactly as your healthcare provider tells you. Your healthcare provider will tell you how many tablets to give for each dose and how often to give them during the day. Do not give more or less Emcitate than prescribed.

• Emcitate tablets must be mixed in room temperature drinking water in a 10 to 12 mL syringe and given as a liquid (suspension), either by mouth or through a feeding tube into the stomach. Read the Instructions for Use for step-by-step directions.
• Do not swallow the tablets whole, and do not chew or crush them.
• Do not mix Emcitate with foods, other liquids, or feeding formulas. Use only room temperature drinking water.
• Prepare no more than 3 tablets in the syringe at a time. If a dose needs more than 3 tablets, prepare it in separate batches.
• The tablets will not fully dissolve. The suspension will look white and cloudy with small particles, which is normal.
• Prepare the dose only when you are ready to give it, and throw away any unused suspension 30 minutes after preparing it.
• Emcitate can be given with or without food.
• Make sure the person receiving the dose is sitting upright.
• If a dose needs half a tablet, break the tablet along the score line and store the unused half as described under storage below.

If you miss a dose: if there are more than 4 hours until the next dose, give the missed dose as soon as possible. If there are less than 4 hours until the next dose, skip the missed dose and give the next dose at the regular time. Do not double the dose.

If vomiting happens: if vomiting happens within 30 minutes of giving a dose, give the dose again. If vomiting happens a second time, do not give another dose, and contact your healthcare provider.

Do not stop Emcitate suddenly or without talking to your healthcare provider. Stopping suddenly can cause symptoms of thyrotoxicosis or make them worse. Your healthcare provider will lower the dose gradually if treatment needs to be stopped.

Blood tests and eye checks: your healthcare provider will check T3 levels in the blood about every 2 weeks while the dose is being adjusted, then about every 6 months once the dose is stable. These blood tests must use a special laboratory method called liquid chromatography tandem mass spectrometry (LC-MS/MS), because Emcitate can affect the results of standard T3 tests. Children younger than 8 years may need regular eye checks during treatment to look for changes in the lens of the eye, such as cataracts.

Emcitate has a boxed warning. Thyroid hormones, including Emcitate, should not be used, either alone or with other medicines, to treat obesity or for weight loss. Taking Emcitate for weight loss may cause symptoms of thyrotoxicosis that could be serious or life-threatening.

Do not use Emcitate if you have primary hyperthyroidism (an overactive thyroid gland).

Do not use Emcitate if you have primary hyperthyroidism.

Before taking or giving Emcitate, tell your healthcare provider about all medical conditions, including if the person taking Emcitate:

• has thyroid problems or takes any other thyroid medicine
• takes a blood thinner (anticoagulant)
• has kidney or liver problems. Emcitate has not been studied in people with kidney or liver problems
• is pregnant or plans to become pregnant. It is not known if Emcitate will harm an unborn baby
• is breastfeeding or plans to breastfeed. It is not known if Emcitate passes into breast milk. Talk to your healthcare provider about the best way to feed the baby during treatment with Emcitate.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and nutritional supplements.

Serious side effects

Emcitate may cause serious side effects, including:

• new or worsening symptoms of too much thyroid hormone (thyrotoxicosis). These symptoms have happened with Emcitate, mostly when treatment is first started and while the dose is being increased. They may also happen if the dose is increased after T3 levels have returned to normal. Symptoms include a faster heart rate, higher blood pressure, diarrhea, excessive sweating (hyperhidrosis), irritability, trouble sleeping (insomnia), and nightmares. Tell your healthcare provider if any of these symptoms happen for the first time or get worse. Your healthcare provider may lower the dose until the symptoms go away.
• serious or life-threatening thyrotoxicosis if used for weight loss. Emcitate should not be used to treat obesity or for weight loss.

Common side effects

The most common side effects of Emcitate include:

• diarrhea
• vomiting
• rash
• excessive sweating (hyperhidrosis).

Tell your healthcare provider if you have any side effect that bothers you or does not go away. These are not all the possible side effects of Emcitate. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to Egetis Therapeutics US Inc. at 1-844-4EGETIS (1-844-434-3847) or to FDA at 1-800-FDA-1088.

The table below shows how often the most common side effects were reported in the two clinical studies of Emcitate. Neither study compared side effects with a placebo group over the full treatment period.

In Study 2, short-lived increases in heart rate (by 10 beats per minute or more) and systolic blood pressure (by 5 mmHg or more) were seen in 35% and 26% of people, respectively, while the dose was being increased. In addition, 30% of people had at least one side effect possibly related to thyrotoxicosis, such as diarrhea, excessive sweating, irritability, trouble sleeping, or nightmares. Most of these happened while the dose was being increased.

Emcitate (tiratricol) is a thyroid hormone receptor agonist that works by attaching to and activating thyroid hormone receptors inside cells, which are normally activated by thyroid hormone.

Unlike the natural thyroid hormones T3 and thyroxine (T4), tiratricol does not need the MCT8 transporter to get into cells. Inside cells, it acts on the signaling between the brain and the thyroid gland (the hypothalamic-pituitary-thyroid axis) and reduces the amount of T3 in the blood in people with MCT8 deficiency.

Tiratricol has a half-life of about 12 hours in a 70 kg adult and about 9.4 hours in a 25 kg child. Emcitate is given once a day or divided into 2 or 3 doses throughout the day. If Emcitate is stopped, T3 levels start rising back toward pretreatment levels within one week.

The Emcitate dose is based on body weight, T3 blood levels, and any symptoms of thyrotoxicosis. The total daily dose can be given once a day or divided into 2 or 3 doses spread through the day. Each tablet contains 350 mcg, and a half tablet contains 175 mcg.

Table 1: Emcitate starting dose and dose increases

The dose is increased until total T3 is below the midpoint of the normal range for age (the maintenance dose), or until the maximum dose for body weight is reached. If total T3 is within the normal range, the dose may be increased further up to the maximum, based on heart rate and blood pressure.

Table 2: Emcitate maximum recommended dosage

Dose reduction for thyrotoxicosis: if symptoms of thyrotoxicosis happen for the first time or get worse and do not go away within 2 weeks, the daily dose is lowered by 175 mcg (10 kg or less) or 350 mcg (more than 10 kg). The dose can be lowered by the same amount every 2 weeks until symptoms go away.

Stopping treatment: the daily dose is lowered by 175 mcg (10 kg or less) or 350 mcg (more than 10 kg) about every 2 weeks.

Table 3: Feeding tube size and maximum tablets per dose

Emcitate can be given through a nasogastric (NG) tube of 6 French and above or a gastrostomy (G) tube of 12 French and above.

• Do not use Emcitate for weight loss.
• Avoid other thyroid medicines unless your healthcare provider tells you otherwise.
• Avoid stimulants, such as caffeine and amphetamines. Taking them with high doses of Emcitate may raise heart rate and blood pressure.
• Do not mix Emcitate with anything other than room temperature drinking water.

Tell your healthcare provider about all the medicines you take, including over-the-counter medicines, vitamins, and nutritional supplements. Emcitate and certain other medicines may affect each other and how they work. No drug interaction studies have been done with Emcitate, but the following interactions are expected:

• Other thyroid medicines (such as levothyroxine, propylthiouracil, and carbimazole) may increase the risk of thyrotoxicosis or hypothyroidism and should be avoided.
• Bile acid sequestrants and ion exchange resins may stop Emcitate from being absorbed properly and should be avoided.
• Iron and calcium supplements may reduce the amount of Emcitate absorbed. If they are needed, give them at the same time each day in relation to Emcitate.
• Proton pump inhibitors (PPIs), used to reduce stomach acid, may increase the absorption of Emcitate. T3 levels may need to be checked when a PPI is started, changed, or stopped.
• Oral estrogen-containing products, anabolic steroids, glucocorticoids, and high-dose salicylates (more than 2 g per day) may change thyroid hormone levels in the blood.
• Medicines that increase liver enzyme activity may increase the breakdown of Emcitate, so a higher dose may be needed.
• Blood thinners (oral anticoagulants) may have a stronger effect with Emcitate, which may increase the risk of bleeding. The anticoagulant dose may need to be lowered, and blood clotting tests should be checked closely.
• Stimulants (such as caffeine, norepinephrine-dopamine reuptake inhibitors, and amphetamines) taken with high doses of Emcitate may raise heart rate and blood pressure and are not recommended.

Know the medicines you take. Keep a list of them and show your healthcare provider and pharmacist when you get a new medicine.

• Store Emcitate tablets in the refrigerator between 36°F and 46°F (2°C to 8°C).
• Keep the tablets in their original blister pack inside the outer carton (or the light-protective packaging from the pharmacy) to protect them from light.
• If a dose uses half a tablet, put the unused half back in the original blister pack, place it in the outer carton or light-protective packaging, and return it to the refrigerator.
• When traveling, use an insulated container or cooler with cool packs. Do not let the medicine or cool packs freeze, and keep them out of direct sunlight, high heat, or extreme cold.
• Do not keep any unused suspension. Throw it away 30 minutes after preparing it.
• Do not throw Emcitate tablets in the trash, flush them down the toilet, or pour them down the drain. Follow your local pharmacy or community guidelines for medicine disposal.
• Keep Emcitate and all medicines out of the reach of children.

Active ingredient: tiratricol

Inactive ingredients: anhydrous dibasic calcium phosphate, corn starch, lactose monohydrate, and magnesium stearate.