Hyzaar 50 mg / 12.5 mg Tablets

Brand Name

This medication is marketed under the trade name Hyzaar, a name widely known among healthcare providers for its cardiovascular benefits.

International Nonproprietary Name (INN)

The active ingredients are recognized globally as losartan potassium and hydrochlorothiazide, ensuring consistent identification across medical systems.

Form of Release

The drug is available as film-coated tablets, designed for oral use with fixed combinations of its active components in various strengths. This tablet form offers ease of use and stability under typical conditions.

Composition

Losartan potassium and hydrochlorothiazide form the primary active substances, working together to manage blood pressure and fluid levels. Supporting ingredients include microcrystalline cellulose, lactose monohydrate, magnesium stearate, and pregelatinized starch, which maintain tablet structure and aid dissolution. The film coating, often hydroxypropyl cellulose, hypromellose, and titanium dioxide, improves swallowability and protects the active components. These elements optimize the combined effects of losartan and hydrochlorothiazide.

Pharmacologic Properties

Pharmacodynamics

This medication combines losartan’s angiotensin II receptor-blocking action with hydrochlorothiazide’s diuretic effects for a dual approach. Losartan blocks the AT1 receptor, preventing vasoconstriction and aldosterone release, relaxing blood vessels and reducing sodium retention. Hydrochlorothiazide boosts this by blocking sodium reabsorption in the distal tubule, increasing urine output and lowering blood volume. Together, they reduce blood pressure effectively, suiting hypertension management. Effects start within hours, peaking over weeks with regular use. This blend balances vascular relaxation and fluid reduction for thorough control.

Pharmacokinetics

After oral intake, the drug’s components absorb differently from the digestive tract. Losartan has about 33% bioavailability, peaking in plasma within an hour, with its active metabolite, EXP3174, peaking at three to four hours after liver metabolism via cytochrome P450 enzymes. Hydrochlorothiazide reaches 60% to 80% bioavailability, peaking within one to two hours, unaffected by meals. Losartan binds 98% to plasma proteins and spreads widely, while hydrochlorothiazide binds 40% to 68% and stays mostly intravascular. Losartan exits 35% in urine and 60% in feces, with half-lives of two hours for the parent and six to nine hours for its metabolite. Hydrochlorothiazide is excreted unchanged in urine, with a half-life of five to 15 hours. Kidney or liver issues may alter these, needing oversight.

Indications for Use

The medication addresses conditions needing strong blood pressure management. It’s mainly used for hypertension, especially when combination therapy is required to hit target levels, cutting cardiovascular risk. It also helps where single-agent treatment falls short, using its dual action for effective pressure control. In some cases, it supports heart failure or fluid retention patients when extra pressure reduction is useful. Its combined approach makes it valuable for enhanced control beyond solo therapy, often part of broader heart care plans.

Contraindications

Certain conditions bar the use of this drug to protect patient health. Hypersensitivity to losartan, hydrochlorothiazide, sulfonamide-derived drugs, or tablet components rules it out, as reactions might range from rashes to anaphylaxis. Severe kidney impairment, like anuria or clearance below 30 mL/min, contraindicates it, given hydrochlorothiazide’s kidney reliance. It’s avoided in severe liver impairment due to losartan’s metabolism and buildup risks. Pregnancy, particularly in later trimesters, prohibits it due to fetal harm risks. Using it with aliskiren in diabetics or those with notable kidney dysfunction is also forbidden, as this raises hypotension and kidney injury odds.

Method of Administration and Dosage

How to Take

Tablets are taken orally, with or without food, offering daily routine flexibility. Swallowing them whole with water ensures proper stomach delivery. Consistent timing maintains steady levels.

Dosage for Adults and Children

Adults with hypertension typically start with one tablet of 50 mg losartan/12.5 mg hydrochlorothiazide daily, adjustable to 100 mg losartan/25 mg hydrochlorothiazide daily based on response, with a max of one 100/25 mg tablet daily. Those switching from losartan alone may begin the combination if more control is needed. Pediatric use lacks firm guidelines, but when prescribed, dosing starts at 0.7 mg per kilogram of losartan and 0.1 mg per kilogram of hydrochlorothiazide daily, adjusted under expert care. Pressure checks guide increments for efficacy and safety.

Dose Adjustment in Specific Conditions

Kidney impairment needs caution; the medication is often avoided if clearance drops below 30 mL/min, though milder cases may use lower doses with hyperkalemia or fluid monitoring. Liver dysfunction suggests starting with 50/12.5 mg daily, as losartan metabolism slows, risking buildup. Elderly or volume-depleted patients may also begin lower to avoid steep pressure drops or dehydration. Regular checks ensure dosing fits individual needs.

Side Effects

The medication may trigger various unintended effects, mostly mild and temporary. Dizziness or lightheadedness, tied to pressure drops, is common, especially at start or dose rises. Fatigue, headaches, or muscle cramps might occur, usually fading with time. Electrolyte shifts, like hypokalemia from hydrochlorothiazide or hyperkalemia from losartan, can cause weakness or heart rhythm changes, notably in at-risk groups. Respiratory issues or cough are less common but noted. Rare severe reactions, like angioedema—swelling of the face or throat—or notable kidney issues, need urgent care. Routine evaluations spot and manage these early.

Overdose

Symptoms of Overdose

Taking too much can lead to severe hypotension, showing as dizziness, fainting, or circulatory collapse from excessive vessel relaxation and fluid loss. Tachycardia might occur to compensate, though bradycardia is possible in extreme cases. Electrolyte issues, like hypokalemia or hyperkalemia, could bring cramps, arrhythmias, or confusion, risking harm if ignored. Symptoms emerge within hours and worsen without action, reflecting the potent dual effects.

First Aid Measures

Stop the drug immediately in an overdose and seek prompt medical help. Recent ingestion may call for activated charcoal under supervision to curb uptake. IV fluids restore pressure and hydration, while electrolyte replacement fixes imbalances like potassium or sodium. Heart and kidney monitoring stabilizes the patient until recovery, aiming to reverse overdose effects fast. Dialysis is rarely useful but may aid extreme cases.

Drug Interactions

Effects on Other Medications

This drug can alter other medications’ effects when combined. It may boost antihypertensive actions, risking sharp pressure drops, needing dose tweaks. NSAIDs might lessen its impact and stress kidneys, especially over time. Potassium-sparing diuretics or supplements raise hyperkalemia odds with losartan, while lithium levels could climb due to reduced clearance, needing plasma checks. Hydrochlorothiazide may heighten antidiabetic effects, risking low glucose, so monitoring is wise.

Compatibility with Alcohol and Food

Alcohol might worsen hypotension or dehydration with the medication, raising dizziness risks, so moderation is advised. Food doesn’t notably affect uptake, though high-sodium intake could counter fluid reduction, suggesting balance. Potassium-rich foods like bananas need care to avoid excess potassium from losartan.

Special Precautions

Use During Pregnancy and Breastfeeding

The drug is barred in pregnancy beyond the first trimester, risking fetal kidney damage or death, per extensive data. Both components appear in breast milk minimally, so nursing mothers should consult their doctor, possibly opting for alternatives to limit infant exposure.

Impact on Driving and Machinery Operation

Dizziness or fatigue, especially at start or dose shifts, may hinder driving or machinery use. Patients should gauge their response before such tasks, ensuring safety.

Considerations for Elderly and Pediatric Populations

Older adults may need lower initial doses due to kidney or volume changes, with monitoring for pressure or dehydration. In children, use is rare and specialist-guided, with weight-based dosing adjusted carefully to avoid overeffects. Tailored care optimizes results.