How does this medication work? What will it do for me?

This combination product contains 2 medications: candesartan and hydrochlorothiazide. Candesartan belongs to a family of medications known as angiotensin II receptor blockers. Hydrochlorothiazide belongs to a family of medications known as diuretics (or "water pills"). This combination medication is used to lower high blood pressure.

Candesartan works by relaxing blood vessels. Angiotensin II is a chemical that the body releases to cause the constriction (tightening up) of blood vessels. Candesartan blocks the action of angiotensin II, resulting in the relaxation of the blood vessels. This relaxation causes the blood pressure to decrease. Hydrochlorothiazide works by causing the body to get rid of excess salt and water.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

16 mg/12.5 mg
Each oblong, biconvex, peach coloured tablet, with a score line on both sides and embossed on one side with "CH" to the left and "16" to the right of the score line, contains 16 mg of candesartan cilexetil and 12.5 mg of hydrochlorothiazide. Nonmedicinal ingredients: carrageenan, corn starch, croscarmellose sodium, ferric oxide red, ferric oxide yellow, lactose monohydrate, magnesium stearate, and povidone.

How should I use this medication?

The usual adult dose is one tablet taken once daily at approximately the same time each day.

Treatment is started separately with candesartan and hydrochlorothiazide. Once the best dose of each individual ingredient is found, the combination medication may then be used at the appropriate strength. Candesartan - hydrochlorothiazide should not be started until the best dose of each ingredient has been determined.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Candesartan - hydrochlorothiazide may be taken with or without food. To protect the medication from unnecessary exposure to moisture and light, leave the medication in the blister package until just before you take it.

To ensure you receive the maximum benefit from the medication, it is important to take this medication regularly and to follow your doctor's instructions regarding blood pressure monitoring.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose and remember within 12 hours, take it as soon as possible and continue with your regular schedule. If more than 12 hours have passed since your usual dose time, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take candesartan – hydrochlorothiazide if you:

  • are allergic to candesartan, hydrochlorothiazide, or any ingredients of this medication
  • are allergic to sulfonamide-containing medications
  • are or plan to become pregnant
  • are breastfeeding
  • are not passing urine
  • have gout
  • have severe kidney disease
  • have severe liver disease
  • have diabetes  or moderate to severe kidney disease and are taking the medication alikskiren
  • have galactose intolerance or glucose malabsorption (a rare hereditary disease)

Do not give this medication to children under 12 months of age.

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • back or leg pain
  • constipation
  • decreased appetite
  • decreased interest in sexual activity
  • diarrhea
  • dizziness or lightheadedness when rising from a lying or sitting position
  • drowsiness
  • headache
  • muscle cramps, pain
  • nausea
  • pins and needles feeling in your fingers
  • trouble sleeping
  • vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • changes in vision (blurred vision, increased eye pressure, eye pain)
  • increased heart rate
  • increased frequency of cold symptoms (ear, head, and nose congestion; sneezing; sore throat; fever)
  • signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
  • signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
  • signs of electrolyte changes (e.g., confusion, drowsiness, dry mouth, muscle fatigue, nausea, thirst, weakness)
  • signs of kidney problems (e.g., increased urination at night, decreased urine production, blood in the urine)
  • signs of kidney failure (e.g., decreased urine production, swelling, fatigue, abdominal pain)
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • swelling of the hands, feet, or ankles
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • unexplained muscle pain, tenderness, or weakness

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Cholesterol: Hydrochlorothiazide may increase cholesterol levels. At the doses used in candesartan – hydrochlorothiazide, this rarely causes problems. However, if you have high levels of cholesterol, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diabetes: Hydrochlorothiazide may make it more difficult to control diabetes. If you have diabetes your doctor may ask that you monitor your blood sugar carefully while taking this medication.

Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

An adjustment of your dose of antidiabetes medications, including insulin, may be needed.

Drowsiness/reduced alertness: Although candesartan - hydrochlorothiazide is unlikely to affect alertness, occasionally dizziness or weariness occurs when treating high blood pressure.

Do not drive, operate machinery, or perform other potentially hazardous tasks until you have determined how this medication affects you.

Fluid and electrolyte balance: As with other diuretics, levels of electrolytes such as potassium, sodium, magnesium, and chloride can be reduced by the use of hydrochlorothiazide. Your doctor will periodically check to see if your electrolytes remain in balance.

Warning signs or symptoms of fluid and electrolyte imbalance include:

  • confusion
  • drowsiness
  • dryness of mouth
  • lethargy
  • low blood pressure
  • muscle pains or cramps
  • muscular fatigue
  • nausea
  • racing heartbeat
  • restlessness
  • seizures
  • thirst
  • vomiting
  • weakness

Gout: Hydrochlorothiazide may increase the level of uric acid in the body, causing an attack of gout for people prone to this condition. If you have a history of gout or kidney stones, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you develop painful, warm, and swollen joints, contact your doctor as soon as possible.

Kidney function: Candesartan can cause changes to kidney function that may result in decreased kidney function, kidney failure, or possibly death. Certain people have experienced changes in kidney function (e.g., people with narrowed blood vessels in their kidneys, or those with severe congestive heart failure). The use of diuretics (water pills), nonsteroidal anti-inflammatory drugs (NSAIDs), or aliskiren may further increase risk of kidney problems for people already at risk for this problem. If you have reduced kidney function, renal artery stenosis (narrowing of blood vessels in the kidneys), or congestive heart failure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have reduced kidney function, you may require lower doses of this medication.

This medication should not be taken by people with severely decreased kidney function.

Liver function: Candesartan is removed from the body by the liver. Rarely, it may cause liver problems. If you have liver disease or decreased liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Candesartan – hydrochlorothiazide is not recommended for people with severely reduced liver function.

Low blood pressure: Occasionally, a larger-than-expected decrease in blood pressure occurs after taking candesartan. In some cases, this happens after the first dose. This is more likely to occur if you take diuretics (water pills) or the medication aliskiren, have a reduced salt intake, are on dialysis, or are experiencing diarrhea or vomiting.

Blood pressure should be monitored more often in these situations. If you have low blood pressure or are just starting to take this medication, you should move slowly from a reclining to an upright position to reduce the risk of dizziness.

Lupus: Hydrochlorothiazide may worsen the symptoms of systemic lupus erythematosus (SLE). If you have lupus, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Potassium levels: Increases in blood levels of potassium occur for approximately 2% of people who take this medication. This rarely causes problems, but your doctor will likely want to monitor your potassium levels through blood tests. Avoid using salt substitutes that contain potassium while you are taking candesartan - hydrochlorthiazide.

Vision changes: Hydrochlorothiazide occasionally causes vision changes including increased eye pressure and myopia (nearsightedness). If you experience any eye symptoms, such as pain or change in vision, contact your doctor as soon as possible.

Pregnancy: Candesartan may cause severe harm to an unborn fetus and should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Women taking candesartan - hydrochlorthiazide who are planning or trying to become pregnant should discuss other, more appropriate medications to control blood pressure with their doctor.

Breast-feeding: It is not known whether candesartan passes into breast milk. Hydrochlorothiazide passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children. It must not be given to children less than 1 year of age.

Seniors: Seniors may be more sensitive to the effects of this medication and may experience more side effects, even at normal adult doses.

What other drugs could interact with this medication?

There may be an interaction between candesartan - hydrochlorothiazide and any of the following:

  • aclidinium
  • alcohol
  • aldesleukin
  • aliskiren
  • allopurinol
  • alpha agonists (e.g., clonidine, methyldopa)
  • alpha blockers (e.g., alfuzosin, doxazosin, tamsulosin)
  • amifostine
  • amphetamines (e.g., dextroamphetamine, lisdexamphetamine)
  • angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
  • angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
  • antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • atropine
  • azelastine
  • barbiturates (e.g., secobarbital, phenobarbital)
  • belladonna
  • benztropine
  • beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
  • beta 2 agonists (e.g., salbutamol, formoterol, terbutaline)
  • brimonidine
  • calcitriol
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • calcium supplements
  • carbamazepine
  • cholestyramine
  • inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
  • oral corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • ciprofloxacin
  • cyclobenzaprine
  • cyclophosphamide
  • cyclosporine
  • diazoxide
  • digoxin
  • disopyramide
  • other diuretics (water pills; e.g., furosemide, triamterene)
  • diabetes medications (e.g., chlorpropamide, glipizide, glyburide, insulin, metformin, nateglinide, rosiglitazone)
  • dofetilide
  • duloxetine
  • eplerenone
  • flavoxate
  • glycopyrrolate
  • guanfacine
  • heparin
  • ipratropium
  • ketotifen
  • levodopa
  • lithium
  • low molecular weight heparins (e.g., dalteparin, enoxaparin, tinzaparin)
  • methylphenidate
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
  • multiple vitamins and minerals
  • narcotics (e.g., codeine, fentanyl, hydrocodone, morphine, oxycodone)
  • nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
  • nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., naproxen, ibuprofen)
  • orphenadrine
  • oxybutynin
  • pentoxifylline
  • phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
  • potassium supplements or medications that increase potassium in the blood
  • rituximab
  • scopolamine
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
  • sodium phosphates
  • tiotropium
  • tolterodine
  • tolvaptan
  • topiramate
  • tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • trimethoprim
  • vitamin D

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.