Losartan-HCTZ 100/12.5 mg is a combination medication prescribed to manage high blood pressure (hypertension). The tablet contains 100 milligrams of Losartan potassium and 12.5 milligrams of Hydrochlorothiazide. This pairing is typically used when a single medication, or monotherapy, has not been sufficient to reach the desired blood pressure goals. Combining two different classes of blood pressure medication into one pill simplifies the treatment plan. The 100/12.5 mg dosage represents a full dose of Losartan combined with a low dose of the diuretic component.
How Losartan and HCTZ Work Together
The two components in this tablet work through distinct mechanisms to achieve a greater blood pressure reduction than either drug alone. Losartan is classified as an Angiotensin II Receptor Blocker (ARB). This drug acts by specifically blocking the Angiotensin II type 1 (AT1) receptors found on blood vessel walls.
Angiotensin II causes blood vessels to tighten and narrow, which increases blood pressure. By blocking the AT1 receptor, Losartan prevents this tightening, allowing the blood vessels to relax and widen. This action reduces the resistance against which the heart pumps, thereby lowering the pressure within the arteries.
Hydrochlorothiazide (HCTZ) is a thiazide diuretic. Its function is to help the kidneys remove excess salt and water from the body. By promoting the excretion of sodium and chloride, HCTZ decreases the overall volume of fluid circulating in the bloodstream.
This reduction in fluid volume decreases the strain on the cardiovascular system, contributing to lower blood pressure. The combination is effective because the diuretic component can sometimes stimulate the body to produce more Angiotensin II, which Losartan then counteracts. Using both medications targets two separate pathways involved in blood pressure regulation, leading to a more powerful and sustained effect.
Directions for Taking the 100/12.5 mg Tablet
The Losartan-HCTZ 100/12.5 mg tablet is prescribed to be taken once daily. Aim to take the medication at approximately the same time each day to maintain a steady drug level and continuous blood pressure control.
The tablet may be taken with or without a meal. The 100/12.5 mg strength is often a maintenance dose, used after lower strengths were not fully effective.
Swallow the tablet whole; do not split, crush, or chew it unless instructed by your doctor. If you forget a dose, take it as soon as you remember, unless it is close to the time for your next scheduled dose. If the next dose is almost due, skip the missed dose entirely. Never double up on the medication, as this could lead to a sudden drop in blood pressure.
The full antihypertensive effect may take three to four weeks after starting therapy to become fully apparent. This medication is for long-term management, so regular monitoring is essential. Your doctor will request periodic blood tests to check kidney function and electrolyte levels, such as potassium. Consistent home blood pressure checks are also recommended.
Potential Side Effects and When to Contact a Doctor
Losartan-HCTZ can cause side effects. Common mild effects include headache, fatigue, and dizziness. Dizziness is common when changing position too quickly, known as orthostatic hypotension. To reduce this, rise slowly before moving.
The diuretic component can affect the body’s electrolyte balance, leading to low potassium levels. Symptoms of an electrolyte imbalance include increased thirst, muscle pain, leg cramps, or irregular heartbeats. If you experience these symptoms, or have severe vomiting or diarrhea, contact your doctor, as these conditions can lead to dehydration and worsen the imbalance.
Angioedema involves swelling of the face, lips, tongue, or throat. This is a severe allergic reaction that can affect breathing and requires immediate medical attention. If you notice signs of swelling, difficulty breathing, or hives, seek emergency care.
Losartan-HCTZ must be discontinued immediately if pregnancy is detected, as it can cause injury or death to the developing fetus, particularly during the second and third trimesters. Other serious symptoms warranting an immediate call to your healthcare provider include changes in vision, eye pain, or signs of kidney problems such as little or no urination, rapid weight gain, or swelling in your hands, feet, or ankles.