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

This combination product contains two active ingredients: quinapril and hydrochlorothiazide. It is used to treat high blood pressure. Quinapril belongs to a class of medications called angiotensin converting enzyme (ACE) inhibitors. It helps to lower blood pressure by relaxing blood vessels and reducing the workload of the heart. Hydrochlorothiazide is a diuretic or "water pill" that helps control blood pressure by getting rid of excess salt and water.

This combination medication is prescribed when your doctor feels it is appropriate for you to be taking both medications. You should already be taking each medication individually before starting this combination medication.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

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?

10 mg/12.5 mg
Each pink, scored, oval, biconvex, film-coated tablet, debossed with "D" on scored side and "18", on other side, contains 10 mg of quinapril as quinapril hydrochloride and 12.5 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, magnesium carbonate, crospovidone, povidone, and magnesium stearate; coating ingredients: hypromellose, hydroxypropyl cellulose, peg 400, titanium dioxide, red and yellow iron oxide.

20 mg/12.5 mg
Each pink, triangular, biconvex, film-coated tablet, debossed with "D" and "19" on either side of a score line on one side and plain on the other side, contains 20 mg of quinapril as quinapril hydrochloride, and 12.5 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, magnesium carbonate, crospovidone, povidone and magnesium stearate; coating ingredients: hypromellose, hydroxypropyl cellulose, peg 400, titanium dioxide, red and yellow iron oxide.

20 mg/25 mg
Each pink, round, biconvex, film-coated tablet, debossed with "D" on one side and "20" on other side, contains 20 mg of quinapril as quinapril hydrochloride and 25 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, magnesium carbonate, crospovidone, povidone, and magnesium stearate; coating ingredients: hypromellose, hydroxypropyl cellulose, peg 400, titanium dioxide, red and yellow iron oxide.

How should I use this medication?

This combination medication is used to make taking the medication more convenient for people who are already taking both of the active ingredients (quinapril and hydrochlorothiazide). It is intended to be used after your doctor has determined the most appropriate dose of the individual ingredients as separate medications.

The usual recommended dose of this medication is one tablet taken once a day, with or without food. The dose will depend on your response to the medication, and on your kidney and liver function. This medication should be taken at the same time each day, preferably in the morning.

Many things can affect the dose of 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.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, 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 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 quinapril - hydrochlorothiazide if you:

  • are allergic to quinapril, hydrochlorothiazide, or any ingredients of the medication
  • are allergic to sulfa (sulfonamide) medications (e.g., sulfamethoxazole)
  • are pregnant or plan to become pregnant
  • are breast-feeding
  • are unable to urinate
  • are taking aliskiren and have diabetes, reduced kidney function, congestive heart failure with low blood pressure, or elevated levels of potassium in your blood
  • are taking other ACE inhibitors or angiotensin receptor blockers (ARBs) and have congestive heart failure with low blood pressure, severe diabetes, reduced kidney function, or elevated levels of potassium in your blood
  • are intolerant of galactose or glucose-galactose
  • have had angioedema (a serious allergic reaction that causes the area around the throat and tongue to swell) after taking any ACE inhibitors (e.g., captopril, enalapril, fosinopril, lisinopril, ramipril)
  • are taking the medication sacubitril/valsartan

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.

  • abdominal pain
  • back pain
  • cold-like symptoms (stuffy or runny nose)
  • constipation
  • cough (dry, persistent)
  • decreased appetite
  • decreased interest in sexual activity
  • diarrhea
  • dizziness
  • drowsiness
  • fatigue or tiredness
  • headache
  • nausea
  • restlessness
  • sensitivity to sunlight
  • sore throat
  • trouble sleeping
  • upset stomach
  • vomiting
  • weakness

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

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

  • changes to the skin or moles (e.g., lump or discoloured patch on the skin that changes slowly; firm red/pink lump; flat scaly patch)
  • fever
  • itchiness
  • joint pain
  • muscle pain or cramps
  • numbness or tingling in fingers
  • rapid, irregular heartbeat
  • rash
  • signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
  • signs of bleeding (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
  • signs of electrolyte imbalance (e.g., muscle pain or cramps, weakness, irregular heartbeat)
  • signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • signs of kidney problems (e.g., decreased urination, nausea, vomiting, swelling of legs, hands, fatigue)
  • signs of liver problems such as abdominal pain, nausea or vomiting, itching of skin, yellow eyes or skin
  • signs of low blood pressure such as dizziness, lightheadedness, or fainting
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • swelling of hands, ankles, or feet
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • symptoms of increased pressure in the eyes (e.g., decreased or blurred vision, eye pain, red eye, swelling of the eye)

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

  • chest pain
  • signs of heart attack (e.g., sudden chest pain or pain radiating to back, down arm, to jaw; sensation of fullness of the chest; nausea; vomiting; sweating; anxiety)
  • signs of nitrogen buildup in the body (e.g., fast heart rate, high blood pressure, confusion, dizziness, poor urine production)
  • 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
  • symptoms of lung inflammation (e.g., shortness of breath, weakness, fever, confusion, and severe difficulty breathing)
  • symptoms of a serious allergic reaction, including angioedema (e.g., hives; swelling of the face, mouth, hands, or feet; and difficulty breathing)
  • vomiting blood

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 using 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.


January 31, 2019

Health Canada has issued new restrictions concerning the use of hydrochlorothiazide. To read the full Health Canada Advisory, visit Health Canada's web site at

Allergic reaction: Some people who are allergic to sulfonamide medications also experience allergic reactions to hydrochlorothiazide. Before you take this medication, inform your doctor about any previous adverse reactions you have had to medications, especially to sulfonamide antibiotics or diabetes medications. Contact your doctor at once if you experience signs of an allergic reaction, such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Angioedema: Angioedema (a serious allergic reaction which causes the area around the throat and tongue to swell) may occur with quinapril, although it is not common. If swelling of the face, tongue, or glottis occurs, stop the medication at once and seek immediate medical attention. If you experience angioedema with quinapril, you should not take any of the other ACE inhibitors, such as enalapril, lisinopril, or perindopril.

People who have had angioedema caused by other substances may be at increased risk of angioedema while taking an ACE inhibitor such as quinapril.

Blood disorders: In rare cases, a low white blood cell count has been reported by people taking this medication. Your doctor may occasionally monitor your level of white blood cells by performing blood tests. Low white blood cell levels may increase your risk for infection. If you notice any signs of infection (e.g., fever, sore throat), contact your doctor as soon as possible.

Breathing: Rarely, people taking hydrochlorothiazide-containing medications experience sudden difficulty breathing, caused by swelling in the lungs. This is called acute respiratory distress syndrome (ARDS) and usually occurs soon after taking the medication. If you experience shortness of breath, worsening difficulty breathing, fever, lightheadedness or dizziness, seek immediate medical attention, as this condition can become life-threatening.

Cholesterol: An increase in cholesterol and triglycerides levels may occur when taking hydrochlorothiazide. Your doctor will monitor you for these changes while you are taking this medication.

Cough: People taking quinapril may develop a dry, persistent cough that usually disappears only after stopping or lowering the quinapril dose of this medication. Inform your doctor of any cough that does not seem to be related to a usual cause.

Diabetes: This medication may make it more difficult for people who have diabetes to control their blood sugar. If you have diabetes, 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 to doses of antidiabetic medications may be required.

Electrolytes: The use of hydrochlorothiazide can reduce the levels of electrolytes such as potassium, sodium, magnesium, and chloride and increase the levels of calcium. Quinapril may cause increases in the amount of potassium in your body. Your doctor will periodically check to see if these levels are in balance, and a potassium supplement may be recommended. 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 and vomiting
  • racing heartbeat
  • restlessness
  • seizures
  • thirst
  • weakness

Gout: Hydrochlorothiazide may increase the level of uric acid in the body. If you have a history of gout, 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.

Glaucoma: Rarely, hydrochlorothiazide can cause an increase in the pressure in the eyes (glaucoma). If you experience decreased sharpness of vision or eye pain shortly after starting to take this medication, contact your doctor immediately. This may be more likely to happen to people who have previously had sulfonamide or penicillin allergies.

Kidney function: Changes in kidney function have been seen in certain people who take this medication. The use of aliskiren may further increase risk of kidney problems for those at risk for this problem. If you have kidney disease, 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.

Let your doctor know if you notice any decrease in urine output or increased swelling of the lower limbs, which suggests an accumulation of fluid due to decreased urination.

Lactose intolerance: This medication contains lactose. If you have galactose intolerance (galactosemia, glucose-galactose malabsorption, or Lapp lactase deficiency) you should not take this medication.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. This medication can also worsen liver function. If you have liver problems, 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. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

If you notice any signs of liver problems (e.g., abdominal pain, itching of skin, or yellow eyes or skin, loss of appetite, vomiting), contact your doctor immediately.

Low blood pressure: Occasionally, blood pressure drops too low after taking this medication. This usually happens after the first or second dose or when the dose is increased. This is more likely to occur for people who are also taking aliskiren or other diuretics (water pills), have a dietary salt restriction, receive dialysis, or are experiencing diarrhea or vomiting. These individuals should be monitored closely by their doctor for the first weeks of treatment and whenever the dose of the medication is increased. To reduce the risk of dizziness, get up slowly from a lying down or sitting position. If low blood pressure causes you to faint or feel lightheaded, contact your doctor.

Excessive sweating and lack of fluid intake may lead to an excessive fall in blood pressure because of reduced fluid in your blood vessels. Vomiting or diarrhea may also lead to a fall in blood pressure. Consult your doctor if you feel your blood pressure is too low.

Lupus: Hydrochlorothiazide can cause the symptoms of systemic lupus erythematosus (SLE) to worsen. If you have SLE, 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. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Psoriasis: Taking quinapril or other ACE inhibitors can cause or worsen psoriasis. Consult your doctor if you’re noticing symptoms of psoriasis, such as itchy, scaly patches on the knees, elbows, trunk, and scalp, or if your psoriasis symptoms are getting worse.

Sensitivity to sunlight: This medication may increase the sensitivity of the skin to sunlight, increasing the risk of sunburn. Avoid exposure to sunlight for long periods of time, particularly between the hours of 10 am and 2 pm, while you are taking this medication and for 7 days after completing treatment. Wear a broad-spectrum sunscreen and lip balm with an SPF of 30 or greater. If you notice any unusual skin rash or peeling, contact your doctor immediately.

Skin cancer: Recent reviews have connected long-term use of hydrochlorothiazide with an increased risk of developing non-melanoma skin cancer. Report any skin changes to your doctor, including firm lumps, patches of discoloured skin, and flat scaly patches of skin. Talk to your doctor about any concerns you may have.

Surgery: It is important that your physician and anesthesiologist know that you are taking this medication before you undergo any surgical procedures requiring general anesthesia.

Pregnancy: ACE inhibitors such as quinapril may cause harm or death to a developing baby if taken during pregnancy. This medication should not be used during pregnancy. If you become pregnant while taking this medication, stop taking it immediately and contact your doctor.

Breast-feeding: These medications pass into breast milk. If you are breast-feeding and taking quinapril and hydrochlorothiazide, 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. Its use by this age group is not recommended.

Seniors: Because of reduced kidney function, seniors have an increased risk of experiencing side effects when taking quinapril - hydrochlorothiazide. Lower doses may be necessary.

What other drugs could interact with this medication?

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

  • acetylsalicylic acid (ASA)
  • aclidinium
  • alcohol
  • aldesleukin
  • aliskiren
  • allopurinol
  • alpha-blockers (e.g., alfuzosin, prazosin, silodosin, tamsulosin, terazosin)
  • amiodarone
  • amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
  • angiotensin receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
  • other angiotensin converting enzyme inhibitors (ACEIs; e.g., captopril, lisinopril, ramipril)
  • antihistamines (e.g., bilastine, cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine, rupatadine)
  • antipsychotics (e.g., aripiprazole, cariprazine, chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • apomorphine
  • atropine
  • azathioprine
  • barbiturates (e.g., butalbital, phenobarbital)
  • benztropine
  • beta-2 agonists (e.g., formoterol, salmeterol, terbutaline)
  • bismuth subsalicylate
  • brigatinib
  • brimonidine
  • bromocriptine
  • buprenorphine
  • butorphanol
  • calcium supplements
  • cholestyramine
  • clidinium
  • colesevelam
  • colestipol
  • inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
  • cyclophosphamide
  • darifenacin
  • desmopressin
  • diabetes medications (e.g., acarbose, canagliflozin, chlorpropamide, glyburide, insulin, lixisenatide, metformin, rosiglitazone)
  • diazoxide
  • digoxin
  • dimenhydrinate
  • disopyramide
  • diuretics (water pills; e.g., furosemide, amiloride, spironolactone, triamterene)
  • duloxetine
  • eplerenone
  • everolimus
  • fesoterodine
  • finerenone
  • flunarizine
  • general anesthetics (medications used to put people to sleep before surgery)
  • glycopyrrolate
  • gold salts
  • grass pollen extract
  • heparin
  • ipratropium
  • iron dextran
  • iron supplements
  • ivabradine
  • ketotifen
  • lanthanum
  • levodopa
  • licorice
  • lithium
  • low-molecular-weight heparins (e.g., dalteparin, enoxaparin, tinzaparin)
  • medications that increase blood levels of potassium (e.g., potassium chloride, salt substitutes containing potassium)
  • methotrexate
  • methylphenidate
  • multivitamins/minerals with ADE
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
  • muscle relaxants (e.g., cyclobenzaprine, orphenadrine)
  • nabilone
  • narcotic medications (e.g., morphine, codeine, hydrocodone, oxycodone, tapentadol, tramadol)
  • nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
  • nonsteroidal anti-inflammatory medications (NSAIDs; e.g., celecoxib, diclofenac, ibuprofen, indomethacin, ketorolac, naproxen)
  • obinutuzumab
  • oral corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • oxybutynin
  • paclitaxel
  • pentoxifylline
  • phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
  • pizotifen
  • polyethylene glycol solution
  • pramipexole
  • pregabalin
  • primidone
  • ranolazine
  • riociguat
  • ropinirole
  • rotigotine
  • sacubitril
  • scopolamine
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline, vortioxetine)
  • sirolimus
  • sodium phosphates
  • sotalol
  • tacrolimus
  • temsirolimus
  • tetracyclines (e.g., doxycycline, minocycline, tetracycline)
  • tiotropium
  • tizanidine
  • tolterodine
  • tolvaptan
  • topiramate
  • tretinoin
  • tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • trimethoprim
  • trospium
  • umeclidinium
  • vilazodone
  • vitamin D analogues (e.g., alfacalcidol, calcitriol, cholecalciferol)
  • yohimbine

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 the ones listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that 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.

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