Vykat XR

Pronunciation: vye kat ex ar
Generic name: diazoxide choline
Dosage form: extended-release tablets (25 mg, 75 mg, 150 mg)

Medically reviewed by Melisa Puckey, BPharm. Last updated on Mar 28, 2025.

What is Vykat XR?

Vykat XR (diazoxide choline) is a new prescription medicine used to treat hyperphagia in Prader-Willi Syndrome. Hyperphagia is a condition when there is an abnormally increased appetite and persistent hunger that cannot be satisfied and can lead to excessive eating. Prader-Willi Syndrome patients using Vykat XR have less hyperphagia compared to patients using a placebo pill. 

Vykat XR is an extended-release tablet that is taken once a day.

Vykat XR mechanism of action is thought to involve activation of the ATP-sensitive potassium (K_ATP) channel which may decrease the secretion of certain peptides that regulate appetite.

Vykat XR FDA-approved indication is to treat extreme hunger, constant thoughts about food, and constant urge to eat that cannot be satisfied with food (hyperphagia) in adults and children 4 years of age and older with Prader-Willi syndrome (PWS). Vykat XR FDA approval was granted on March 26, 2025, to Soleno Therapeutics, Inc.

Vykat XR launch date is expected to begin in early April 2025.

Vykat XR clinical trials

Vykat XR FDA approval was based on a well-controlled clinical trial and safety data collected over an average of 3.3 years of treatment during the clinical development program. Its effectiveness was confirmed in a 16-week randomized withdrawal phase of Study 2-RWP (Study C602-RWP, NCT03714373), a Phase 3, multi-center, double-blind, placebo-controlled trial. During this phase, individuals who were switched to a placebo showed a significant worsening of hyperphagia compared to those who continued taking Vykat XR.

What is Prader-Willi Syndrome?

Prader-Willi Syndrome is a rare genetic neurodevelopmental condition that leads to physical, mental and behavioral problems, but the defining symptom is hyperphagia. Prader-Willi Syndrome is caused by a missing or altered gene on chromosome 15 that interferes with the normal function of the hypothalamus, a region of the brain responsible for regulating key bodily processes. The hypothalamus helps control hormone release, and when it doesn't function properly, it can disrupt hunger regulation, growth, cognition, muscle development, sexual development, body temperature, mood, and sleep.

Vykat XR is used to reduce hyperphagia in Prader-Willi Syndrome.

Vykat side effects

Common Vykat XR side effects

The most common Vykat XR side effects are:

• Excessive hair growth, hypertrichosis 36% 
• Swelling of hands feets, limbs face, edema 27% 
• Low blood sugar levels, hypoglycemia 17%
• Rash 12%
• Fever 6% 
• Joint pain 5%
• Influenza 5% 
• Common cold symptoms 5%

These common side effects occurred in 5% or more of Vykat XR patients in Study 1.

Related/similar drugs

Serious side effects

Vykat XR may cause serious side effects, including:

High blood sugar levels (hyperglycemia) 

High blood sugar levels (hyperglycemia) is common side effect that can also be severe, sometimes leading to diabetic ketoacidosis (increased ketones in the blood). Diabetic ketoacidosis is a serious condition that  can be life-threatening and needs to be treated in a hospital.

To reduce the risk of diabetic ketoacidosis your healthcare professional will

• monitor your blood sugar levels before you start this medicine, at least once a week for the first 2 weeks once you start the tablets, then once every 4 weeks and as needed during treatment.
• If you have an increased risk of having high blood sugar (hyperglycemia) your healthcare provider will check your blood sugar more often during the first few weeks of treatment.
• You will have another measurement of blood sugar levels called your HbA1c, this will be done before treatment then every 3 months as needed during treatment.

If you get hyperglycemia during treatment with VYKAT XR, your healthcare provider may:

• give you medicines to treat hyperglycemia or change your dose if you already take them
• change your dose, temporarily stop, or permanently stop VYKAT XR

Tell your healthcare provider if you get any of the following signs and symptoms of:

High blood sugar:

• Feel very thirsty
• Need to urinate more frequently than usual
• Have higher amounts of urine than usual
• Feel more hungry than usual
• Weight loss

Diabetic ketoacidosis

• nausea
• vomiting
• stomach-area (abdominal) pain
• feel weak or very tired
• trouble breathing

Too much fluid in your body (fluid overload)

Fluid overload causing swelling in the body (edema) is a common side effect which can also be severe. 

Your healthcare provider may decrease your dose or temporarily stop Vykat XR if you get fluid overload. Tell your healthcare provider if you have  trouble breathing or get any other signs or symptoms of fluid overload such as swelling of your legs, ankles, or feet, or unusual swelling anywhere in your body.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088

Who should not take this medicine?

Do not take Vykat XR if you are allergic to the active ingredient diazoxide, any of the inactive ingredients in this medicine. 

You should not take Vykat XR if you are allergic to medicines called thiazides.

Before taking this medicine 

Before taking this medicine, tell your healthcare provider about all of your medical conditions, including if you:

• have diabetes or prediabetes
• are sick
• plan to have surgery
• drink alcohol very often
• are dehydrated or have lost a lot of body fluid
• have heart problems or a history of swelling in your legs or other parts of your body
• have liver or kidney problems

Pregnancy

Before taking this medicine tell your healthcare provider if you are pregnant, or plan to become pregnant. Vykat XR  may harm your unborn baby. 

Tell your healthcare provider right away if you become pregnant during treatment with this medicine.

Breastfeeding

Before taking this medicine tell your healthcare provider if you are breastfeeding  are breastfeeding or plan to breastfeed. VYkat XR  passes into your breast milk, and it is not known if it can harm your baby. Tell your healthcare provider if you plan to breastfeed during treatment with this medicine.

How should I take Vykat XR?

• Take Vykat XR tablets once a day with or without food.
• Swallow Vykat XR tablets whole.
• Do not split, crush, or chew the tablets. 

Your healthcare provider will decide how much VYKAT XR you will take and may slowly increase your dose when you first start taking this medicine.

Take Vykat XR exactly as your healthcare provider tells you to take it. 

You should not miss a dose of your tablets. If you miss a dose, take the missed dose as soon as you remember. Do not take 2 doses of Vykat  XR at the same time to make up for a missed dose. If you missed a dose of VYKAT XR and did not remember to take another dose, call your healthcare provider to discuss what you should do next. 

If you take too much of this medicine, call your healthcare provider or Poison Help Line at 1-800-222-1222 or go to the nearest hospital emergency room right away.

The dose of Vykat XR tablets is not the same as diazoxide oral suspension. Do not change between Vykat XR tablets  and diazoxide oral suspension products. 

Vykat XR dosing information

The recommended Vykat XR dose is based on body weight. 

The Vykat XR dose starts at low and increases over several weeks until the maintenance dose is reached on week 7.

Your dose may be interrupted or reduced for clinically significant increases in fasting glucose, HbA1c or if there is clinically significant fluid overload.

Following dosage interruption or a missed dose of 7 days or more, re-titration will be required.

Vykat XR tablet strengths

Vykat XR: 25 mg, 75 mg, and 150 mg

Interactions

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking Vykat XR with certain other medicines may affect the way Vykat XR or the other medicine works and may increase your risk of side effects.

Strong CYP1A2 Inhibitors: Reduce Vykat XR dosage.

CYP1A2 Substrates: Using CYP1A2 Substrates with Vykat XR tablets is not recommended.

Do not change your dose or stop any medicines you take or start any new medicines without talking to your healthcare provider first during treatment with this medicine. Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

Especially tell your healthcare provider if you take:

• medicines to lower blood sugar
• growth hormones
• corticosteroids
• diuretics (water pills)
• phenytoin
• warfarin

Not all possible drug interactions are listed here.

Vykat XR Patient Support

Soleno One is a patient support program designed to help you access Vykat XR tablets from specialty pharmacy partners. Your doctor completes the Vykat XR Start Form and sends it to the Soleno One program. You will then receive a call from the Soleno One support team, and delivery of your medicine will be arranged.

Soleno One will also help you with education and resources, understanding your insurance, provide information on financial support and support access for patients who do not have insurance coverage.

The Soleno One team can be reached toll-free at 1-(833)-SOLENO-1 (1-833-765-3661) from 8 a.m. to 8 p.m. ET Monday through Friday.

Vykat XR Copay Program

With the Vykat XR Copay Program, you may pay as little as $0 for monthly out-of-pocket costs if you have a valid prescription for Vykat XR from a licensed prescriber for a use that is approved by the FDA. You must also have commercial insurance (those whose prescription is paid for by government healthcare programs are not eligible) and you must live in the United States.

Storage

• Store at room temperature between 68°F to 77°F (20°C to 25°C).
• Close the bottle tightly after each dose. 
• Keep tablets dry (protect from humidity).

Ingredients 

Active ingredient: diazoxide choline 

Inactive ingredients: carnauba wax, colloidal silicon dioxide, dibasic calcium phosphate dihydrate, hypromellose magnesium stearate, polyethylene oxide, silicified microcrystalline cellulose, talc, titanium dioxide, and triacetin.

Company

Vykat XR Soleno Therapeutics, Inc., 100 Marine Parkway, Suite 400, Redwood City, CA 94065

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer