This is a combination product that contains 2 medications: olmesartan and hydrochlorothiazide. It is used to lower high blood pressure.

Olmesartan belongs to the class of medications called angiotensin II receptor blockers and helps to lower blood pressure by blocking the action of a chemical (angiotensin II) that causes blood vessels to constrict or tighten, thereby relaxing blood vessels. Hydrochlorothiazide belongs to the class of medications called diuretics or "water pills" and helps control blood pressure by getting rid of excess salt and water.

This combination medication is used to treat mild to moderate high blood pressure for people who require treatment with both olmesartan and hydrochlorothiazide. This medication is most often used when a person has taken olmesartan and hydrochlorothiazide as separate medications without any problems.

When blood pressure is allowed to remain high for a long time, the blood vessels of the heart, kidneys, and brain may become damaged. This puts a person at increased risk for heart attack and stroke as well as kidney failure and blindness. Keeping blood pressure in the normal range can reduce the risk for these conditions.

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.

This combination medication is used to make dosing more convenient for people who are already taking both of these medications (olmesartan and hydrochlorothiazide) separately. Once the dose of each medication has been established, the combination tablet can be started.

The recommended dose is 1 tablet once daily. The usual adult dose of olmesartan ranges from 20 mg to 40 mg once daily, while the usual adult dose of hydrochlorothiazide ranges from 12.5 mg to 25 mg once daily.

This medication may be taken with or without food, but should be taken in the same manner each day.

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 to take this medication exactly as prescribed by your doctor. If you miss a 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, protect it from light and moisture, and keep it out of the reach of children.

20 mg/12.5 mg
Each reddish-yellow, round, biconvex, film-coated tablet, debossed with "12" on one side and "20" on the other side, contains 20 mg of olmesartan medoxomil and 12.5 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, cellulose microcrystalline, hydroxy propyl cellulose, low substituted hydroxypropyl cellulose, magnesium stearate, hypromellose, titanium dioxide, talc, iron oxide yellow, and iron oxide red.

40 mg/12.5 mg
Each reddish-yellow, oval, biconvex, film-coated tablet, debossed with "12" on one side and "40" on the other side, contains 40 mg of olmesartan medoxomil and 12.5 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, cellulose microcrystalline, hydroxy propyl cellulose, low substituted hydroxypropyl cellulose, magnesium stearate, hypromellose, titanium dioxide, talc, iron oxide yellow, and iron oxide red.

40 mg/25 mg
Each pink, oval, biconvex, film-coated tablet, debossed with "25" on one side and "40" on the other side, contains 40 mg of olmesartan medoxomil and 25 mg of hydrochlorothiazide. Nonmedicinal ingredients: lactose monohydrate, cellulose microcrystalline, hydroxy propyl cellulose, low substituted hydroxypropyl cellulose, magnesium stearate, hypromellose, titanium dioxide, talc, iron oxide yellow, and iron oxide red.

Do not use olmesartan - hydrochlorothiazide if you:

• are allergic to olmesartan, hydrochlorothiazide, or any ingredients of the medication
• are allergic to other sulfonamide-derived (sulfa) medications (e.g., sulfamethoxazole)
• are breast-feeding
• are pregnant or may become pregnant
• have anuria (inability to pass urine)
• have diabetes or kidney disease and are taking aliskiren
• have galactose intolerance (a rare hereditary condition)

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
• diarrhea
• dizziness
• drowsiness
• fatigue
• headache
• increased sensitivity to sun
• muscle restlessness
• nausea
• rash
• red, itchy patches on skin
• spinning sensation
• upper respiratory tract infection (such as colds or sinus infections)
• 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 check with your doctor or seek medical attention.

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

• blood in the urine
• dizziness or light-headedness when rising from a lying or sitting position
• irregular or pounding, rapid heartbeat
• non-melanoma skin cancer (e.g., slowly changing discoloured patch on the skin; red, pink lumps on the skin; flat, scaly patches)
• severe long-lasting diarrhea with weight loss
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of gout (e.g., joint pain, swelling and warmth of joints)
• signs of infections (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 the feet and ankles)
• signs of liver damage (yellowing of skin or whites of eyes, abdominal pain, loss of appetite, brown urine, light-coloured stools, tiredness, or weakness)
• signs of muscle damage (e.g., unexplained muscle pain, tenderness or weakness, or brown or discoloured urine)
• signs of electrolyte imbalance (e.g., muscle pain or cramps, weakness, irregular heartbeat, lack of coordination, thirst, confusion, muscle fatigue, weakness, nausea)
• swelling legs, ankles, or hands
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, dry skin, headache, blurred vision, fatigue)
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)
• vision changes

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

• chest pain
• severe skin rash, including skin blistering and peeling (possibly with headache, fever, coughing, or aching before the rash begins)
• signs of a serious allergic reaction (swelling of face, lips, tongue, or throat; hives; difficulty breathing)
• sudden development of kidney problems (e.g., no urine production, swelling legs and feet)
• symptoms of increased pressure in the eyes (e.g., decreased or blurred vision, eye pain, red eye, swelling of the eye)

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.

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.

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.

Cholesterol: Cholesterol and triglyceride levels may increase when taking hydrochlorothiazide. Your doctor may want you to have regular blood tests to monitor your cholesterol levels while you are taking this medication. If you have increased cholesterol or triglyceride levels, 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 for people with diabetes to control their blood sugar levels. A dose adjustment of diabetes medication, including insulin, may be required. Your doctor may ask you to test your blood sugar levels more frequently when you are taking this medication.

Drowsiness/reduced alertness: Blood pressure medications may cause drowsiness or dizziness. Avoid driving or operating machinery until you know whether the medication affects you in this way.

Fluid and electrolyte balance: Your levels of electrolytes such as potassium, sodium, magnesium, chloride, and calcium may change due to the hydrochlorothiazide in this medication. If you experience symptoms of fluid and electrolyte imbalance such as muscle pains or cramps; dry mouth; numb hands, feet, or lips; or racing heartbeat, contact your doctor as soon as possible. Your doctor may want you to have regular blood tests to monitor these levels while you are taking this medication.

Gout: This medication may cause high levels of uric acid in the blood or cause gout. Symptoms of an acute gout attack include sudden pain, swelling, and stiffness in the affected joint, often the big toe. You may also experience a fever. If this is your first attack, seek medical attention as soon as possible. If you have 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.

Kidney function: Olmesartan - hydrochlorothiazide can cause changes to the kidneys 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. This medication should not be taken by people with severely impaired kidney function.

Liver function: People with reduced liver function may need a lower-than-usual dose of olmesartan; therefore, it may be necessary to use the components of the combination product separately. If you have reduced 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. This medication is not recommended for people with severe liver impairment.

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.

Low blood pressure: Occasionally, a greater-than-expected drop in blood pressure occurs after taking this medication. It is more likely to occur if you are taking additional diuretics (water pills), or aliskiren, have reduced salt intake, are on dialysis, have diarrhea, or are vomiting. Blood pressure should be monitored more often in these situations. To reduce the risk of dizziness, people with low blood pressure or those just starting to take this medication should stand or sit up slowly when getting up from a lying down or sitting position. If low blood pressure causes you to faint or feel lightheaded, contact your doctor.

Lupus: Some people taking hydrochlorothiazide have experienced worsening or activation of lupus. 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.

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 of hydrochlorothiazide have connected long-term use of the medication with an increased risk of developing non-melanoma skin cancer. This risk increases with longer use (more than 3 years) and higher doses. Check your skin regularly for any new skin lesions. Talk to your doctor about any concerns you may have.

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: Olmesartan should not be taken by people who are or may become pregnant. It can cause severe harm or death to an unborn baby if the medication is taken during pregnancy. If you become pregnant while taking this medication, stop taking the medication and contact your doctor immediately.

Breast-feeding: It is not known if olmesartan passes into breast milk. Hydrochlorothiazide does pass into breast milk. If you are breast-feeding and taking olmesartan - hydrochlorothiazide, it may affect your baby. Do not breast-feed while you are taking this medication.

Children: The safety and effectiveness of using this medication have not been established for children. This medication is not recommended for children.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other 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.

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.