Compare Atenolol vs. Tenex

Head-to-head comparisons of medication uses, side effects, ratings, and more.



Lowers blood pressure and controls heart rate. Tenormin (Atenolol) is good for controlling chest pain and treating heart failure and heart attack with fewer side effects than other beta blockers. You have to take it on an empty stomach, and you can't miss doses.Treats ADHD and lowers blood pressure. Tenex (Guanfacine) can be used to treat both blood pressure and ADHD, but it's not recommended as a first-line treatment for either problem.
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Reviews for Tenormin (Atenolol)
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446 reviews

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Side effects
  • Tiredness 13%
  • Dizziness 7%
  • Cold extremities 7%
  • Low mood disorder 3%
  • Vivid dreams 2%
  • Shortness of breath 2%
  • Leg pain 2%
  • Nausea 2%
  • Diarrhea 1%
  • Fatigue 1%
More Atenolol side effects »
  • Drowsiness 31%
  • Fatigue 8%
  • Dizziness 7%
  • Headache 5%
More Tenex side effects »
How it works
Tenormin (Atenolol) is a selective beta blocker that works specifically on the heart. It lowers blood pressure by slowing down the heart and making it less work to pump.Tenex (Guanfacine) is a centrally-acting alpha agonist medication. It lowers blood pressure by slowing down the heart rate and relaxing the blood vessels. It's not clear how Tenex (Guanfacine) works in ADHD, but it's used when stimulants haven't worked or can't be used in people.
Type of medication
Beta blocker
Prescription only
Alpha agonist
Prescription only
Available as
  • Pill
  • Pill
  • Extended release
Used for (click to learn more)
Risk factors for serious side effects
  • Suddenly stopping Tenormin (Atenolol)
    • Taking calcium channel blockers
    • Major surgery requiring anesthesia
    • Diabetes
      • Taking clonidine
      Detailed Tenormin (Atenolol) risks & warnings »
      • Taking other medications that cause sedation or sleepiness
      • Stopping Tenex (Guanfacine) suddenly to treat high blood pressure
      Detailed Tenex (Guanfacine) risks & warnings »
      Pregnancy category
      DFDA pregnancy category (Weigh risks vs. benefits)

      Research studies with real people found harmful effects on unborn babies, but the benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

      See the FDA package insert
      BFDA pregnancy category (Probably safe)

      Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

      See the FDA package insert
      No specific alcohol-related info.
      • Limit the amount of alcohol you drink while taking this.
      No specific food-related info.No specific food-related info.
      Kidneys and liver
      No specific kidneys and liver-related info.No specific kidneys and liver-related info.
      No specific sex-related info.No specific sex-related info.
      No specific sleep-related info.No specific sleep-related info.
      No specific weight-related info.No specific weight-related info.
      Upsides and benefits
      • A first-choice treatment to prevent chest pain (angina).
      • A first-choice treatment for heart failure and heart attack.
      • At lower doses, Atenolol has fewer side effects than most beta blockers because it targets the heart and doesn't cross into the brain and central nervous system.
      • The same medication treats two different things, high blood pressure and attention deficit hyperactivity disorder (ADHD).
      • It's not a "controlled medication".
      • Used to control ADHD when stimulant medications haven't worked or can't be used due to other medical problems.
      • Available as a generic medication, so it should be more affordable than other options.
      Downsides and risks
      • You have to take Atenolol on an empty stomach.
      • Taking a beta blocker might make you feel more tired or out of breath during exercise or normal daily routines. This gets better for most people, but for some might not go away.
      • Not a first-choice treatment for high blood pressure according to the latest guidelines, except if you have heart failure or heart disease. As a second choice, your doctor might add it to medicines you're already taking if your blood pressure is still too high.
      • You can't miss doses. Stopping Atenolol suddenly can cause your blood pressure to go up suddenly, which raises the risk of heart attack and stroke.
      • Can hide symptoms of low blood sugar if you're diabetic.
      • Doesn't control ADHD as well as stimulants do, so it's used as a second-line medication.
      • Not a preferred drug to control blood pressure.
      • Can't be stopped suddenly, especially for blood pressure, since the blood pressure can dramatically increase.
      Tips from our pharmacists for people taking the medication
      • Take it on an empty stomach.
      • Can cause dizziness in the first few days.
      • Check your blood pressure 1 week after starting this medicine, and tell your doctor if it hasn't improved.
      • Can cause fatigue and insomnia.
      • Can hide symptoms of low blood sugar. Be careful if you're diabetic.
      • Don't stop taking this medicine suddenly.
      • Don't stop taking Tenex (Guanfacine) without talking to your doctor first.
      • Limit the amount of alcohol you drink while taking this.
      • Drink plenty of liquids and don't get overheated while taking Tenex (Guanfacine).
      • You can feel sleepy the first few times you take it, or when your dose is increased. Don't drive or do anything that requires concentration until you know how the medication affects your body.
      • Can take up to 2 weeks for the maximum effect.
      Learn more
      More about AtenololSide effectsReviews & ratingsAlternativesFDA package insert
      More about TenexSide effectsReviews & ratingsAlternativesFDA package insert