Opinions in Healthcare

Onyda XR

On May 24, 2024, the FDA approved Onyda XR (clonidine hydrochloride), a liquid non-stimulant medication for attention deficit hyperactivity disorder (ADHD). Developed by Tris Pharma, Onyda XR is a centrally acting alpha 2 -adrenergic agonist that can be used once daily at bedtime orally as monotherapy or as adjunctive therapy to central nervous system stimulants in pediatric patients 6 years of age and older. This medication is expected to be in pharmacies during the second half of 2024. 


Traditionally, clonidine is an antihypertensive medication that lowers blood pressure and heart rate by relaxing arteries and increasing blood supply to the heart. In addition to treating hypertension, clonidine has other FDA-approved indications such as the management of tics found with Tourette syndrome, adjunct therapy for cancer-related pain, and treatment for ADHD in children. The exact mechanism of action of clonidine in the treatment of ADHD is unknown. However, it is proposed that postsynaptic alpha-2-agonist stimulation regulates subcortical activity in the prefrontal cortex. This helps to regulate symptoms of hyperactivity, impulsivity, and inattention. 

Safety and Efficacy 

This approval of Onyda XR comes from adequate evidence presented by studies that evaluated extended-release tablets of clonidine hydrochloride in patients with ADHD. In an 8-week randomized, double-blinded, placebo-controlled, fixed-dose study of pediatric patients 6 to 17 years old it was found that ADHD symptoms were statistically significantly superior in clonidine hydrochloride extended-released treated patients compared with placebo-treated patients at the end of 5 weeks. Another clinical study examined the use of Onyda XR use as adjunctive therapy by treating a group of patients with a psychostimulant (methylphenidate or amphetamine) alone and another group of patients with clonidine hydrochloride extended-release adjunct to a psychostimulant. This study found that at the end of the 5 weeks, ADHD symptoms measured by the ADHDRS-IV total score were statistically significantly improved in clonidine hydrochloride extended-release plus stimulant group compared with the stimulant alone group. 

Patient Information/Counseling

Onyda XR is contraindicated in patients with a history of a hypersensitivity reaction to clonidine. This medication is best taken once daily at bedtime with or without food. Some common adverse reactions (incidence in <5%) in monotherapy is somnolence, nightmares, constipation, dry mouth, and insomnia. Common adverse reactions when used as adjunct therapy to psychostimulant is fatigue, decreased appetite, and dizziness. Patients should avoid driving or operating heavy machinery until they know how the medication affects them as Onyda XR can cause sleepiness. Onyda XR also can cause dose-related hypotension and bradycardia. It is crucial for patients to begin this medication on a low dose, titrate slowly, and be counseled on how to monitor vital signs such as blood pressure.

“People with ADHD require a range of therapeutic options that are designed for their individual needs because not every medication or type of therapy works for every patient”, said Dr. Ann Childress. This approval of Onyda XR allows for a convenient option for patients requiring improved ADHD control. 

Pooja Dasgupta, PharmD Candidate 2025