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Specific Ziac Precautions and Warnings

Some warnings and precautions to be aware of prior to taking Ziac include the following:
  • You should not abruptly stop taking beta blockers such as Ziac, as serious problems (including heart attacks) may result. Your healthcare provider will advise you on how to safely stop taking this medication. People are usually advised to slowly reduce the dose over a period of one to two weeks, with careful monitoring, and to minimize physical activity during this time. Let your healthcare provider know if you develop chest pain or any other problems while stopping Ziac.
  • Like all beta blockers, Ziac can worsen heart failure in some situations. However, beta blockers are also useful for the treatment of heart failure. If you have this condition, your healthcare provider may need to monitor you closely while you take Ziac. Let your healthcare provider know immediately if your heart failure symptoms become worse while taking this drug.
  • Beta blockers can worsen breathing problems like asthma or COPD. If you have breathing problems, check with your healthcare provider before taking Ziac. Even though it is a "cardioselective" beta blocker (which makes it less likely to cause breathing problems), such problems are still possible, especially with a high Ziac dosage.
  • If you will be having surgery, make sure your surgeon and anesthesiologist know you take Ziac, as it may affect the choice of medications used during surgery.
  • The bisoprolol component of Ziac can mask some of the symptoms of low blood sugar (hypoglycemia), particularly the "racing heart" feeling. This can cause serious problems for people with diabetes, who need to be able to sense that they have low blood sugar in order to correct it before it becomes life-threatening.


  • Drugs that contain hydrochlorothiazide, including this medication, can sometimes cause a potentially dangerous eye reaction (a particularly dangerous type of glaucoma). This reaction usually occurs within days to weeks of starting the drug. Because this reaction can permanently damage vision, let your healthcare provider know right away if you develop vision changes and/or eye pain. The main treatment for this reaction is to stop taking this medication, although other treatment (including surgery) may sometimes be necessary. 


  • The hydrochlorothiazide component of Ziac may increase the risk of high blood sugar (hyperglycemia), particularly in people with diabetes.
  • Beta blockers can mask some of the symptoms of an overactive thyroid (hyperthyroidism). Stopping Ziac suddenly could cause symptoms of a "thyroid storm" (a sudden and severe worsening of hyperthyroidism symptoms).
  • Ziac may affect electrolytes in the blood, including sodium, calcium, potassium, magnesium, and chloride. Therefore, your healthcare provider will regularly check these levels during treatment. If you notice any symptoms of a possible electrolyte imbalance, contact your healthcare provider. These symptoms may include:
    • Dry mouth and increased thirst
    • Weakness
    • Tiredness
    • Restlessness
    • Seizures
    • Confusion
    • Muscle pain and cramps
    • Decreased urine output
    • Weak or irregular heartbeat
    • Nausea and vomiting.
  • In rare cases, parathyroid problems have been reported in people taking hydrochlorothiazide (one of the components of Ziac). Also, hydrochlorothiazide should be stopped before having a parathyroid function test. As part of these tests, calcium levels are often checked, and hydrochlorothiazide can cause increased calcium levels.
  • Hydrochlorothiazide has been reported to worsen systemic lupus erythematosus or, in some cases, even cause the condition.
  • Hydrochlorothiazide is known to worsen gout.
  • Ziac can potentially interact with many other medications (see Ziac Interactions).
  • The kidneys and liver help remove Ziac from the body. Therefore, if you have kidney or liver disease, your healthcare provider may need to monitor your response to this medication more closely, and a lower dosage may be recommended.
  • If you have an anaphylactic allergy (the type that affects the entire body and often interferes with breathing), Ziac may make you more sensitive to the allergen and may make the usual treatments (such as epinephrine or an EpiPen®) less effective. In addition, the hydrochlorothiazide component is more likely than other drugs to cause allergic reactions. People with a history of asthma or allergies may be more likely to have an allergic reaction to hydrochlorothiazide.
  • Ziac is considered a pregnancy Category C medication. This means that it may not be safe for use during pregnancy, although the full risks are not currently known (see Ziac and Pregnancy).
  • Ziac passes through breast milk in humans. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Ziac and Breastfeeding).
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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