Valsartan and Hydrochlorothiazide

Valsartan and hydrochlorothiazide is a combination oral tablet approved to treat high blood pressure (hypertension) in adults. It is used in three main situations:

• As add-on therapy when a single blood pressure medication (valsartan alone or HCTZ alone) isn't controlling blood pressure well enough
• As replacement therapy for patients already taking both valsartan and hydrochlorothiazide as separate pills who are tolerating them well
• As initial combination therapy for patients whose blood pressure is high enough that one drug is unlikely to be sufficient — both Diovan HCT and generic valsartan and hydrochlorothiazide tablets are approved for this use, though this approach is not recommended if you are dehydrated or low on body fluids

Lowering blood pressure with this medication reduces the risk of stroke and heart attack. It is not a cure for hypertension and works best as part of a broader plan that may include diet, exercise, limiting sodium, and managing other risk factors.

Valsartan and hydrochlorothiazide tackles high blood pressure from two directions at once. Valsartan is an angiotensin II receptor blocker (ARB): it blocks a hormone called angiotensin II from binding to receptors in blood vessel walls and the adrenal glands. Normally, angiotensin II causes blood vessels to tighten and tells the body to hold on to sodium — both of which raise blood pressure. By blocking those signals, valsartan helps blood vessels relax and blood pressure fall. Hydrochlorothiazide (HCTZ) is a thiazide diuretic that acts on the kidneys, prompting them to excrete more sodium and water. Less fluid in circulation means less pressure on vessel walls. Because valsartan counteracts some of the potassium loss that HCTZ tends to cause, the two ingredients complement each other well.

Valsartan and hydrochlorothiazide tablets are taken by mouth once a day and can be taken with or without food. Your prescriber will start you at an appropriate dose and may adjust it after 1 to 2 weeks depending on how your blood pressure responds; full effects after a dose change are usually seen within 2 to 4 weeks. Always follow your prescriber's specific instructions — do not adjust your dose on your own.

• Can be taken with or without a meal
• Dosed once daily
• May be used alongside other blood pressure medications if your doctor recommends it
• If you miss a dose, follow your pharmacist's or prescriber's guidance — do not double up

Most people tolerate valsartan and hydrochlorothiazide well, but some side effects can occur:

• Dizziness or lightheadedness (especially when standing up quickly)
• Headache
• Nasopharyngitis — stuffy or runny nose and sore throat
• Nausea, upset stomach, or diarrhea
• Fatigue or weakness
• Back pain or muscle aches
• Cough
• Rapid or irregular heartbeat (palpitations)

More serious reactions — like a sharp drop in blood pressure, significant changes in kidney function, dangerously high or low potassium, sudden eye pain with vision changes, or signs of a severe allergic reaction — require prompt medical attention. Contact your doctor or seek emergency care right away if any of these occur.

• Pregnancy: This medication can cause serious injury or death to a developing baby. Stop it immediately and call your doctor if you become pregnant.
• Low blood pressure (hypotension): Most likely to occur if you are dehydrated, on a low-salt diet, or taking high-dose diuretics. Lie down and seek help if you feel faint.
• Kidney function: This medication can affect the kidneys, especially in people who already have kidney disease, renal artery narrowing, severe heart failure, or low fluid volume. Your doctor should check kidney function periodically.
• Potassium imbalance: HCTZ can lower potassium (hypokalemia); valsartan can raise it (hyperkalemia). Both extremes can affect heart rhythm. Your electrolytes will need monitoring.
• Acute angle-closure glaucoma: HCTZ can rarely cause a sudden eye pressure spike with eye pain and blurred vision — a medical emergency. Seek care immediately if this happens.
• Metabolic effects: HCTZ can raise blood sugar, uric acid (worsening gout), cholesterol, and calcium levels, and can activate or worsen lupus in susceptible people.
• Lithium toxicity: This combination can significantly raise lithium blood levels. If you take lithium, your levels must be monitored closely.

Several medications, supplements, and substances can interact with valsartan and hydrochlorothiazide:

• Lithium — blood levels can rise to toxic amounts; close monitoring required
• NSAIDs and COX-2 inhibitors (ibuprofen, naproxen, celecoxib) — can blunt blood pressure control and raise the risk of kidney damage, especially in older adults or those on diuretics
• Potassium-raising agents (potassium supplements, potassium-sparing diuretics like spironolactone, salt substitutes, heparin) — can push potassium to dangerous levels when combined with valsartan
• Aliskiren — must not be combined in patients with diabetes; avoid in patients with significant kidney impairment
• Other ACE inhibitors or ARBs — dual blockade of the renin-angiotensin system increases risk of low blood pressure, high potassium, and acute kidney failure
• Diabetes medications (insulin, oral agents) — HCTZ can raise blood sugar, so dose adjustments may be needed
• Cholestyramine or colestipol — can greatly reduce HCTZ absorption; take HCTZ at least 4 hours before or 4–6 hours after these resins
• Alcohol, sedatives, narcotics, or barbiturates — can worsen dizziness upon standing (orthostatic hypotension)
• Digoxin — low potassium or magnesium caused by HCTZ can increase the risk of digoxin toxicity
• Cyclosporine — may increase risk of high uric acid and gout when combined with HCTZ; may also increase valsartan exposure

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Pregnancy: Do not use this medication if you are pregnant or planning to become pregnant — it can seriously harm the baby
• Breastfeeding: Breastfeeding is not recommended while taking this medication
• Children: Safety and effectiveness have not been established in pediatric patients
• Older adults: May be more sensitive to blood pressure drops and electrolyte changes; no dose adjustment is required but closer monitoring may be appropriate
• Kidney impairment: Use in severe kidney impairment (creatinine clearance at or below 30 mL/min) has not been established; mild-to-moderate impairment generally does not require dose adjustment
• Liver impairment: Valsartan dose adjustment is not needed for mild-to-moderate liver disease; no dosing recommendation exists for severe liver disease. HCTZ can trigger hepatic coma in those with serious liver disease
• Allergy to sulfonamide drugs or penicillin: You may have a higher risk of the rare acute angle-closure glaucoma reaction from HCTZ
• Diabetes: HCTZ can affect blood sugar control; also, aliskiren must not be combined with this medication if you have diabetes
• Gout or high uric acid: HCTZ can raise uric acid and trigger gout flares
• Lupus: HCTZ may activate or worsen systemic lupus erythematosus
• Dehydration or low sodium/fluid status: Correct before starting, as blood pressure may drop too low

Taking too much valsartan and hydrochlorothiazide is most likely to cause a significant drop in blood pressure (hypotension) and a fast heart rate (tachycardia); a very slow heart rate (bradycardia) is also possible. Electrolyte problems — particularly low potassium, low sodium, and low chloride — and dehydration from excessive fluid loss are the other main concerns with HCTZ overdose. If overdose is suspected, seek emergency medical care immediately; supportive treatment is the main approach, as valsartan is not removed by dialysis.

Valsartan measurably blocks the blood pressure-raising effects of angiotensin II. After the HCTZ component is absorbed, its diuretic (urine-producing) effect begins within about 2 hours, peaks around 4 hours, and lasts roughly 6 to 12 hours. HCTZ can lower potassium and magnesium levels in the blood, while valsartan has very little effect on potassium by itself — and tends to counteract the potassium loss caused by HCTZ when the two are combined. Alcohol, sedatives, and narcotic pain medications can amplify the blood pressure-lowering effect of this combination, increasing the risk of dizziness upon standing.

Valsartan reaches peak blood levels about 2 to 4 hours after a dose and has an elimination half-life of roughly 6 hours; it is mostly cleared through the stool. Food does not meaningfully affect HCTZ absorption, but it can reduce how much valsartan the body absorbs — so taking the tablet consistently (with or without food each day) is more important than timing it around meals. HCTZ is absorbed within 2 to 5 hours, has an elimination half-life of about 10 hours, and is excreted largely unchanged in the urine. In older adults, valsartan exposure is notably higher and its half-life longer than in younger people, and HCTZ clearance is also reduced — so older patients may need careful monitoring.

Store at 25ºC (77ºF); excursions permitted to 15-30ºC (59-86ºF). Protect from moisture. Dispense in tight container (USP).