Prescription onlyLower-cost generic available



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Treats ADHD and lowers blood pressure.

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Prescription onlyLower-cost generic available

Our bottom line

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.


  • 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.


  • 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.

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What to expect when you take Tenex (Guanfacine)

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Tips from our pharmacists
  • 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.
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Side effects for Tenex (Guanfacine)

From clinical trials of Tenex / HIgh blood pressure (1 mg)  ( 120)

  • Dry mouthDry mouth10% for Tenex vs.0% for placebo
  • DrowsinessDrowsiness10% for Tenex vs.8% for placebo
  • HeadacheHeadache7% for Tenex vs.8% for placebo
  • FatigueFatigue5% for Tenex vs.2% for placebo
  • Any side effectAny side effect5% for Tenex vs.0% for placebo
  • Muscle weaknessMuscle weakness3% for Tenex vs.0% for placebo
  • DizzinessDizziness2% for Tenex vs.8% for placebo

Manufacturers don’t say how common these side effects are

  • Constipation
  • Impotence

Risks and Warnings for Tenex (Guanfacine)

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    • Higher risk if:
    • Taking other medications that cause sedation or sleepiness

    People report having sleepiness or sedation while on Tenex (Guanfacine). You're at higher risk for this if you're taking other medications that have similar effects. Don't drive or do anything that requires concentration until you know how Tenex (Guanfacine) affects you.

Means that some groups have a high risk of experiencing this side effect

Tips from pharmacists and people taking Tenex (Guanfacine)

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The FDA category for this medication is B. It is advised that you: Probably safe
  • Tips from our pharmacists
  • Limit the amount of alcohol you drink while taking this.
  • This was prescribed for my son when he was about 8-10years old for Tourettes and with the thought it would supplement is ADHD med. It didn't seem effective for either for him. He was drowsy with this med.
  • My son takes it in the evening. Seems to help him sleep and lessens the frequency of night terrors. Daytime he is more focused and has less frequent/severe behaviours.