API: Clonidine

What Is Clonidine and How Does It Work?

Clonidine hydrochloride is a centrally-acting alpha-agonist hypotensive agent. The drug is FDA-approved to treat hypotension in adults and works by changing certain nerve impulses to relax blood vessels.1 Specifically, clonidine stimulates alpha-2 receptors in the central nervous system, which then decreases sympathetic activity and decreases both blood pressure and heart rate. Clonidine may be prescribed on its own or in conjunction with another drug and can be delivered through pills, transdermal patches, or parenterally.2

Clonidine is also FDA-approved to treat Attention Deficit Hyperactivity Disorder (ADHD).3 Although the exact mechanism of action is not known, clonidine is believed to regulate norepinephrine in the brain, a neurotransmitter linked to ADHD. Clonidine is not a stimulant, but may be prescribed alone or with stimulants.

For more information, including a MSDS sheet, please see PNA’s Clonidine page.

Approved Indications

Hypertension: Clonidine is approved to treat hypertension through different delivery modes: orally, through a transdermal patch, or parenterally. Patches offer lower, steadier dosages than oral pills and are more convenient, but can be costlier.4 Parenteral administration is only recommended in patients who have cancer or neuropathic pain that may require concomitant opiates.5

ADHD: Clonidine is approved to treat children who have ADHD. The oral drug reduces ADHD symptoms alone or in combination with stimulants. Clonidine may also reduce aggression and insomnia associated with any concomitant stimulants.

Side Effects and Drug Interactions

Common side effects in patients taking clonidine include6:

  • Dry mouth
  • Constipation
  • Drowsiness
  • Dizziness
  • Fatigue or insomnia
  • Nausea or vomiting
  • Headache
  • Nervousness or depression
  • Loss of appetite or weight gain
  • Decreased sexual ability
  • Muscle aches or cramps
  • Dry, itching, or blurry eyes

Patients experiencing the following symptoms should contact their healthcare provider right away:

  • Rash or hives
  • Difficulty breathing, swallowing, or talking
  • Swelling of the face or limbs
  • Any form of heart disease, or a history of heart disease or stroke
  • Slow heartbeat or other heart rhythm disorders
  • Hypotension
  • Tumors of the adrenal gland
  • Kidney disease

Patients allergic to clonidine should not take this medication. Patients with any of the following conditions should consult with their physicians before starting this medication7:

Patients who are pregnant, or who plan on becoming pregnant, should consult their physician before starting this medicine.

Many drugs can have severe interactions with clonidine, including8:

  • Sedating drugs, such as those that contain alcohol or benzodiazepines
  • Medications that decrease heart rate, such as
    • Tizanidine
    • Amiodarone
    • Calcium channel blockers
    • Digoxin
    • Beta blockers

Patients already on these drugs should consult their pharmacist or physician before starting clonidine.

Latest News and Research

Clonidine was developed in the mid-1960s as a side result from a drug being developed to treat nasal congestion.9 Since then, clonidine has been valuable not only as a drug, but also as a tool in understanding the importance of central α2-adrenoceptors and how they work.

Physicians often prescribe clonidine for off-label indications, including treatment of10:

  • Pain management in cancer patients
  • Tourette’s syndrome
  • Migraines
  • Stress/sleep disorders
  • Withdrawal symptoms of alcohol, nicotine, and narcotics

Buying Guide

PNA is a recommended bulk supplier of Clonidine and other APIs. You can learn more about Clonidine here.

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Show 10 footnotes

  1. “Clonidine (Oral Route),” 2015, http://www.mayoclinic.org/drugs-supplements/clonidine-oral-route/description/drg-20063252
  2. “Practical Considerations for Optimal Transdermal Drug Delivery,” 2012, http://www.medscape.com/viewarticle/757497_2
  3. “New Agents and Second-line Therapies for Attention-Deficit/Hyperactivity Disorder,” 2002, http://www.medscape.com/viewarticle/441910_3
  4. “When a Patch Is Better than a Pill,” October 1, 2012, http://bottomlinehealth.com/when-a-patch-is-better-than-a-pill/
  5. “Clonidine Injection,” December 1, 2015, http://www.drugs.com/pro/clonidine-injection.html
  6. “What Is Clonidine?” 2015, http://www.everydayhealth.com/drugs/clonidine
  7. “Clonidine, December 1, 2015, http://www.drugs.com/clonidine.html
  8. “Alpha-2 agonists,” http://www.straighthealthcare.com/alpha-2-agonists.html
  9. “A historical perspective: development of clonidine,” June 2000, http://www.sciencedirect.com/science/article/pii/S152168960090079X
  10. “Drug Record: Clonidine,” http://livertox.nih.gov/Clonidine.htm