Compare Hydrochlorothiazide vs. Catapres

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

Microzide
(Hydrochlorothiazide )

Catapres
(Clonidine)

Lowers blood pressure. Removes extra water from your body. Microzide (Hydrochlorothiazide (Hctz)) is a well-tolerated water pill that's often the first-choice treatment for mild high blood pressure.Lowers blood pressure. Catapres (Clonidine) is a good addition if you need more than one medicine to control your blood pressure, but it has a lot of side effects. You can't miss doses.
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Reviews & ratings
Button Group. All currently active
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4.467153284671533Hydrochlorothiazide
Reviews for Microzide (Hydrochlorothiazide (Hctz))
47%
of people say Microzide (Hydrochlorothiazide (Hctz)) is worth it
31%
say it works well
15%
say it's a big hassle
Reviews for Catapres (Clonidine)
42%
5% vs. Microzide (Hydrochlorothiazide (Hctz))
33%
+2% vs. Microzide (Hydrochlorothiazide (Hctz))
34%
19% vs. Microzide (Hydrochlorothiazide (Hctz))
Side effects
HydrochlorothiazideCatapres

The Hydrochlorothiazide FDA package insert doesn’t have numbers about how common side effects are.

More about Hydrochlorothiazide side effects »

The Catapres FDA package insert doesn’t have numbers about how common side effects are.

More about Catapres side effects »
How it works
HydrochlorothiazideCatapres
Microzide (Hydrochlorothiazide (Hctz)) is a thiazide diuretic (water pill). It works in the kidneys to make you urinate more, which removes extra water and certain electrolytes. This lowers blood pressure and swelling.Catapres (Clonidine) is an alpha-2 agonist. It works in the brain to tell your blood vessels to relax, and it lowers the activity of certain stress hormones. This lowers blood pressure.
Type of medication
HydrochlorothiazideCatapres
Antihypertensive
Diuretic
Prescription only
Antihypertensive
Alpha agonist
Prescription only
Available as
HydrochlorothiazideCatapres
  • Pill
  • Pill
  • Extended release
  • Patch
Used for (click to learn more)
HydrochlorothiazideCatapres
Risk factors for serious side effects
HydrochlorothiazideCatapres
  • Current electrolyte imbalance
  • History of sulfa allergies
  • History of gout
  • Current kidney problems
    Detailed Microzide (Hydrochlorothiazide (Hctz)) risks & warnings »
    • Sudden discontinuation of medicine
    • Taking with alcohol
    • Taking other medicines that make you less alert
    • Age 65 years or older
    • Using other medicine(s) that slows the heart
    Detailed Catapres (Clonidine) risks & warnings »
    Pregnancy category
    HydrochlorothiazideCatapres
    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
    CFDA pregnancy category (Weigh risks vs. benefits)

    Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

    See the FDA package insert
    Alcohol
    No specific alcohol-related info.No specific alcohol-related info.
    Food
    No specific food-related info.No specific food-related info.
    Kidneys and liver
    • Doesn't work well in people with severe kidney problems.
    • Requires routine blood tests to check kidney function.
    No specific kidneys and liver-related info.
    Sex
    No specific sex-related info.No specific sex-related info.
    Sleep
    No specific sleep-related info.
    • Can cause drowsiness, headache, dizziness, and dry mouth.
    Weight
    No specific weight-related info.No specific weight-related info.
    Upsides and benefits
    HydrochlorothiazideCatapres
    • Works well to get rid of extra fluids in your body through urination.
    • A first-choice blood pressure treatment for many people. Works especially well for African Americans.
    • Lowers the risk of heart attack and stroke.
    • Good option if you have both high blood pressure and heart failure.
    • Raises calcium levels in the body, so it can be good for people with osteoporosis to slow down bone loss and even help with new bone formation.
    • Most people have very few side effects.
    • Can be added to other blood pressure-lowering medicines if you need additional blood pressure control.
    • Available in a weekly patch for people that aren't good at taking medicine by mouth.
    • Works in the brain, so it can help treat some nervous system and psychiatric conditions.
    • Under the brand name Kapvay, it's used to treat ADHD in children and teenagers.
    Downsides and risks
    HydrochlorothiazideCatapres
    • Makes you urinate more often.
    • Doesn't work well in people with severe kidney problems.
    • Has a lot of side effects compared to other blood pressure-lowering medicine because it works in the brain.
    • The pill form can make some people sleepy, dizzy, and have dry mouth.
    • You can't miss doses. Stopping Clonidine suddenly can cause your blood pressure to go up suddenly, which raises the risk of heart attack and stroke.
    Tips from our pharmacists for people taking the medication
    HydrochlorothiazideCatapres
    • Starts working in about 2 hours.
    • Makes you urinate more often, so avoid taking it at bedtime.
    • Can cause dizziness in the first few days.
    • Tell your doctor about any dizziness, fatigue, or muscle weakness that doesn't go away.
    • Requires routine blood tests to check kidney function.
    • Check your blood pressure 1 week after starting this medicine, and tell your doctor if it hasn't improved.
    • Usually taken together with other medicines for better blood pressure control.
    • Can cause drowsiness, headache, dizziness, and dry mouth.
    • If side effects don't go away, talk to your doctor about alternatives.
    • The weekly patch form can have fewer side effects.
    • Don't stop taking this medicine suddenly.
    • Extended release tablet also used to treat ADHD.
    • Check your blood pressure 1 week after starting this medicine, and tell your doctor if it hasn't improved.
    Learn more
    More about HydrochlorothiazideSide effectsReviews & ratingsAlternativesFDA package insert
    More about CatapresSide effectsReviews & ratingsAlternativesFDA package insert