Q. I took clonidine for several years to help with both blood pressure and hot flashes. I took the pill only at night. The nightmares didn’t start right away, but after they did, they became progressively more frequent until they were occurring about once every week or so. I became afraid to go to bed anymore, not knowing if I’d wake up in a panic from another nightmare. I also suffered sleep paralysis, which is very scary.

A. Clonidine (Catapres) is a unique blood pressure drug that was first approved by the FDA in 1974. It was first available as a tablet and then later also as a transdermal skin patch (Catapres-TTS).

Although the FDA has approved clonidine only for treating hypertension, physicians prescribe it for a number of “off-label” uses to:

  • Ease symptoms of withdrawal from narcotic pain relievers
  • Ease symptoms of withdrawal from nicotine
  • Relieve hot flashes of menopause
  • Alleviate nerve pain associated with diabetes (diabetic neuropathy)
  • Help control pain caused by cancer
  • Help control symptoms of ADHD

How well clonidine works for these off-label uses remains controversial. Without large-scale, long-term, well-controlled scientific trials it is hard to really know.

Clonidine & Nightmares:

If you check most monographs or standard references for clonidine you will not discover nightmares or sleep paralysis as a side effect. But if you dig a bit deeper into the official prescribing information you will discover that “sleep disorder, and vivid dreams or nightmares” are listed. How common these symptoms are is anyone’s guess. In one informal, web-based study, we found that this side effect may take several months to show up. As a result, it would never have been reported in clinical trials and consequently it isn’t in the standard list of side effects.

Sleep paralysis is another side effect that could easily be missed in clinical trials. That’s because investigators rarely question subjects about this sort of adverse reaction. It can indeed be a terrifying experience. Sleep paralysis sometimes happens upon awakening, when the person just begins to regain consciousness but has no muscle control and feels paralyzed. To get a sense of what this scary situation is like, you may wish to read this account from one of our visitors.

Other Side Effects of Clonidine (Catapres)

  • Dry mouth (40% of patients may experience); dry nose
  • Drowsiness, sedation, fatigue (one third of patients may experience)
  • Dizziness (16% of patients may experience)
  • Constipation (10% of patients may experience); stomach pain, loss of appetite
  • Low blood pressure, especially upon standing (dizziness)
  • Blurred vision, dry eyes
  • Headache
  • Anxiety, nervousness, agitation, restlessness
  • Delirium, delusions, hallucinations, depression
  • Hair loss, rash, hives, itching
  • Fever
  • Sexual problems, loss of libido, erectile dysfunction, urinary difficulties
  • Slow pulse, arrhythmias, irregular heart rate
  • Blood disorders
  • Muscle cramps, leg cramps, joint pain

Does Clonidine Have Anticholinergic Activity?

One of the more disconcerting complications of clonidine is its anticholinergic-like activity. Many health professionals are not aware that this blood pressure drug might alter the way the body reacts to the neurochemical acetylcholine (hence its possible anticholinergic action). But when you see symptoms such as dry mouth, dry eyes, constipation, drowsiness, blurred vision, difficult urination and confusion, they are red flags that the drug could have substantial anticholinergic activity.

That means that older people (over the age of 65) could be extremely vulnerable to brain fog, delirium or hallucinations. And such complications could lead to a false diagnosis of Alzheimer’s disease or dementia. To learn more about this under-recognized problem we suggest either our Guide to Drugs and Older People or the chapter on senior citizens in our book Top Screwups Doctors Make and How to Avoid Them.

There is not yet adequate research to prove clonidine has strong anticholinergic action, but the common symptoms of this drug are so suggestive that we think researchers should examine this possibility seriously.

Clonidine Withdrawal: A Potentially Deadly Reaction

NEVER stop taking clonidine suddenly! Missing a dose of clonidine can cause a serious or even potentially life-threatening withdrawal reaction. Symptoms can include anxiety, agitation, headache, tremor and worst of all, a sudden spike in blood pressure. The blood pressure elevation can be so great as to trigger a stroke. Although the FDA advises a gradual withdrawal if clonidine must be discontinued, the agency doesn’t provide much detail. Here are the FDA’s recommendations:

“When discontinuing therapy with CATAPRES [clonidine] tablets, the physician should reduce the dose gradually over 2 to 4 days to avoid withdrawal symptomatology.”

The FDA also warns that if a person is taking clonidine and has to undergo surgery:

“Administration of Catapres® (clonidine hydrochloride, USP) tablets should be continued to within 4 hours of surgery and resumed as soon as possible thereafter. Blood pressure should be carefully monitored during surgery and additional measures to control blood pressure should be available if required.”


Clonidine comes with a lot of unpleasant baggage. Although it may be a good choice for some patients, we think it should rarely, if ever, be prescribed to older patients. It is on the “Beers List” of drugs older people should generally avoid. (Other medications on the Beers List can be found in both our Guide to Drugs and Older People and our book Top Screwups Doctors Make and How to Avoid Them.

Have you ever taken clonidine? How well did it work to control your blood pressure? Did your doctor prescribe it for one of the off-label uses listed above? If so, did it work? Did you experience side effects? We would like to learn more about your experience, so please use the space below to enter your comment. Thanks for sharing your story.

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  1. Emma

    I went to the ER thinking I had kidney failure or a stone. Turns out I had shingles. Ouch! They discovered high blood pressure & gave me Clonidine. I have been on Clonidine for hypertension (high Blood Pressure) for 8 months now. I used to only take it when I could feel the blood pounding in my ears every couple of days. Well, that was wrong. The Doctor just shook his head & warned me about the rebound effects that send your BP higher. Well, crap. I hate taking any medicine everyday. But now I take 0.1mg twice a day. I decided to take it 12 hours apart.

    From the beginning, it knocked me out about 1 &1/2 hours after taking it. I substitute teach so that wasn’t very good for me. The slump usually lasts about 45 minutes. When working, I power through it by sheer obstinance & coffee. When at home & it hits me, I take a nap. The Doc tried Norvasc. NO! I got a very fast heart rate, dizzy, & dots before my eyes. So I went back to Clonidine.

    I have dry mouth every time. That tells me the medicine has kicked in. It has bothered my intestinal movement because I have intermittent intestinal peristalsis which is caused by previous neck injury. The injury caused damage to the nerves that control digestion. My digestion doesn’t move right & sometimes stops altogether which is an ER visit. It has nothing to do with Clonidine but because the drug works to suppress Acetylcholine, then it slows down my digestion even further. On the other hand, it has helped my asthma a lot! Doc wants to add in a beta blocker but that messes with asthma, so not yet.

    My side effects are:
    1.dry mouth & nose
    2. drowsiness for 45 minutes
    3. spike in BP if I go off it
    4.intestinal slow down of digestion due to previous condition.

    My BP runs 130/80 or 90 depending on coffee intake.
    Other than 2 baby aspirin when neck pain gets bad, it’s the only drug I am on daily. I’m over 65 & growing old stinks! But hey, the alternative ain’t so great either so………. for me, Clonidine works.

    Best to everyone finding your correct medicine.

  2. Sue

    Added info. .I didn’t have any fatique or headaches and it did help with the nervousness and irrability of an anti estrogen drug.

  3. Sue

    Also helped with effects of Anastrozole. Other than the kidney and oral precautions I find it helps with my adult ADHD very much.

  4. Sue

    I was given clonidine for reduction of morphine for chronic pain. The pain is back and not allowing me a semi normal life. Clonidine did help some but helped in other areas veey much.

  5. Lapper

    Really knocks you out. Watch your dosage. I think once you find your dosage, it will make the side effects much better. I experience dry mouth, fatigue and weakness with 0.2 mg twice a day, so I backed-it down to 0.1mg once a day and am so much better now.

    I was put on for anxiety, off-label medication, and it has helped with the flushing and hot skin issues.

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