Onyda XR (clonidine HCI)

What Is Onyda XR?

Onyda XR (clonidine hydrochloride) is a liquid non-stimulant ADHD medication approved for the treatment of ADHD symptoms in pediatric patients aged 6 and older. As of December 2025, it is the only liquid non-stimulant ADHD medication with nighttime dosing.

Onyda XR became available for the treatment of attention-deficit hyperactivity disorder (ADHD) in the United States on October 1, 2024.¹

The U.S. Food and Drug Administration (FDA) approved Onyda XR on May 24, 2024, as a monotherapy treatment for ADHD or as an adjunctive therapy to approved central nervous system (CNS) stimulant medications in pediatric patients 6 years of age and older. The safety and effectiveness of Onyda XR in children under 6 years of age are unknown.

What Is the Active Ingredient in Onyda XR?

Clonidine hydrochloride (HCL)

How Does Onyda XR Work?

Tris Pharma developed Onyda XR with its proprietary LiquiXR® technology, which converts immediate-release drugs into extended-release formulations for once-daily dosing.¹

LiquiXR® technology works by attaching the active ingredient in Onyda XR to ion-exchange resins, small carrier particles that temporarily “hold onto” the medicine. The extended-release particles are coated with polymer films of varying thicknesses. After Onyda XR is swallowed, naturally occurring positively charged GI exchange ions in the stomach and intestines pass through the polymer coating, releasing the medicine. The thickness of the polymer coating controls how fast the drug is released and extends its duration of action. This method allows for a single, once-daily dose of Onyda XR to be released in a gradual, continuous, and extended-release profile over 24 hours.

By taking Onyda XR at night, patients experience its main therapeutic effects the following day. Dosing at bedtime may help manage potential side effects, such as somnolence and sedation, as any initial drowsiness occurs while the patient is already asleep.

Onyda XR is considered a centrally acting alpha2-adrenergic agonist medication that belongs to the same class of drugs as alpha-2 agonists, such as guanfacine (Intuniv) and clonidine (Kapvay).

How Do You Use Onyda XR?

Onyda XR is taken by mouth once daily at bedtime, with or without food. It is supplied in 30 mL, 60 mL, or 120 mL bottles and includes one oral dosing dispenser and one press-in bottle adapter.

To use, shake the bottle gently for at least 10 seconds before each dose. Carefully measure the dose using the oral syringe that comes with the medication. Rinse the syringe with water after each use.

Do not stop taking Onyda XR without talking to your healthcare provider. If you miss a dose of Onyda XR, skip the missed dose and take the next dose at its regular scheduled time. Do not take more Onyda XR in 24 hours than your healthcare provider prescribed for your daily dose.

For the 30 mL and 60 mL bottles, throw away any unused Onyda XR remaining 30 days after first opening the bottle. For the 120 mL bottle, throw away any unused Onyda XR remaining 60 days after first opening the bottle.

What Does Onyda XR Taste Like?

Onyda XR is orange-flavored.

Who Should Take Onyda XR?

Onyda XR is an extended-release oral suspension non-stimulant option for pediatric patients 6 years and older who have difficulty swallowing pills. It is also suitable for patients with ADHD who experience adverse side effects from stimulants or who respond poorly to stimulant medications.

In addition, clinicians may prescribe Onyda XR along with a stimulant to treat ADHD symptoms in patients who require a longer-acting therapy. Combination therapy is an option for patients who need longer durations of drug coverage than a stimulant dose can provide on its own.

What Is the Typical Dosage for Onyda XR?

The recommended starting dose for Onyda XR is 0.1 mg daily at bedtime. Clinicians may titrate the dose of Onyda XR in increments of 0.1 mg per day at weekly intervals, up to the maximum recommended dosage of 0.4 mg once daily at bedtime.

*For updated information about dosages, interactions, and precautions, see the Onyda XR drug monograph on WebMD.

What Side Effects Are Associated with Onyda XR?

According to Onyda XR prescribing information,² the most common adverse reactions associated with the medication’s use as monotherapy include:

• somnolence
• fatigue
• irritability
• nightmares
•  insomnia
• constipation
• dry mouth

The most common adverse reactions with its use as an adjunct therapy include:²

• somnolence
• fatigue
• decreased appetite
• dizziness

These are not all the possible side effects of Onyda XR. For a complete list of potential side effects, refer to the Safety & Side of Effects of Onyda XR.

What Precautions Are Associated with Onyda XR?

Before taking Onyda XR, tell your healthcare provider about any medical conditions, including kidney problems, low or high blood pressure, heart problems, including slow heart rate or other heart rhythm problems, or if you have ever had a stroke or stroke symptoms.

Treatment with Onyda XR can cause dose-related decreases in blood pressure and heart rate, which can increase your risk of fainting. If you have a history of passing out or have other medical problems, your risk is higher. Your healthcare provider should check your heart rate and blood pressure before starting treatment and regularly during treatment with Onyda XR. Do not become dehydrated or too hot (overheated) to decrease your chance of passing out during treatment with Onyda XR.

Taking Onyda XR with alcohol or medicines may cause or worsen sleepiness or dizziness, which could cause slow reaction times (sedation and somnolence). Do not drive, operate heavy machinery, or do other dangerous activities until you know how Onyda XR affects you. Do not drink alcohol or take other medicines that make you sleepy or dizzy during treatment with Onyda XR until you talk with your healthcare provider.

Suddenly stopping Onyda XR can cause high blood pressure to return if you have a history of high blood pressure. Suddenly stopping Onyda XR may also cause withdrawal symptoms, including headache, increased heart rate, nausea, flushing or warm feeling, lightheadedness, chest tightness, and nervousness or anxiety. Tell your healthcare provider if you have been vomiting and cannot take Onyda XR, as you may be at risk for rebound hypertension.

What Drug Interactions Are Associated with Onyda XR?

You should not take Onyda XR if you are allergic to clonidine.

Avoid concomitant use of CNS depressants with Onyda XR. Clonidine may potentiate the CNS-depressive effects of alcohol, barbiturates, or other sedating drugs.

Avoid concomitant use of antihypertensive drugs, as clonidine potentiates the hypotensive effects of clonidine.

Concomitant use of tricyclic antidepressants with clonidine can increase blood pressure and may counteract the hypotensive effects of clonidine.

Avoid use of Onyda XR with agents known to affect sinus node function or AV nodal conduction (e.g., digitalis, calcium channel blockers, and beta-blockers) due to a potential for additive effects such as bradycardia and AV block.

According to Onyda XR prescribing information, prolonged experience with clonidine in women over several decades, based on published literature — including controlled trials, a retrospective cohort study, and case reports — has not identified a drug-associated risk of major congenital disabilities, miscarriage, and adverse maternal or fetal outcomes.

Patients should consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for Onyda XR and any potential adverse effects on the breastfed child from Onyda XR or from the underlying maternal condition.

Share a list of all vitamins or herbal supplements and prescription and non-prescription medications you take with the pharmacist when you fill your prescription. Inform all doctors and physicians that you are taking Onyda XR before surgery or laboratory tests.

For a complete list of all possible drug interactions, side effects, and precautions, refer to Onyda’s drug label information for consumers and healthcare professionals.

What Studies Are Associated with Onyda XR?

The FDA based its approval of Onyda XR on two 8-week studies of clonidine hydrochloride extended-release tablets in pediatric patients aged 6 to 17 years who met DSM-IV criteria for ADHD.^{3, 4}

Monotherapy Study:
In the first placebo-controlled monotherapy trial, 256 pediatric patients were assigned to either a group where they were given .02 mg of clonidine XR daily, .o4 mg of clonidine XR daily, or a placebo.³ By week 5, patients receiving clonidine XR showed significantly greater improvements in ADHD symptoms from baseline compared with the placebo group (as measured by the ADHD-RS-IV total score). The most common adverse reactions included somnolence, fatigue, irritability, insomnia, nightmares, constipation, and dry mouth.

Adjunctive Therapy Study:
A second 8-week study evaluated clonidine XR as an adjunctive therapy in 198 children who had an inadequate response to prior stimulant treatment (methylphenidate or amphetamine).⁴ In this randomized, double-blind, placebo-controlled trial, patients received either clonidine XR plus a stimulant or a stimulant plus a placebo. By week 5, those treated with clonidine XR in combination with a stimulant showed statistically significant improvements in ADHD symptoms (measured by the ADHD-RS-IV total score) compared with the stimulant-only group. The most common adverse reactions included somnolence, fatigue, decreased appetite, and dizziness.

Refer to Onyda XR’s study results for more information.

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