What is the drug EP 155?: Unveiling Hydrochlorothiazide

October 5, 2025 •

3 min read

According to the U.S. Food and Drug Administration (FDA), the imprint code 'EP 155' identifies a specific tablet of the generic medication hydrochlorothiazide. This medication, commonly referred to as a 'water pill,' is a thiazide diuretic prescribed to treat high blood pressure and edema.

Quick Summary

The tablet marked EP 155 contains hydrochlorothiazide, a diuretic used to treat high blood pressure and fluid retention associated with various medical conditions. This prescription-only medication functions by helping the kidneys eliminate excess water and salt from the body.

Key Points

Identification: The imprint 'EP 155' denotes a tablet containing the generic medication hydrochlorothiazide.
Mechanism: Hydrochlorothiazide works as a diuretic, increasing the excretion of sodium and water from the kidneys to reduce fluid volume.
Medical Uses: It is prescribed to treat high blood pressure (hypertension), fluid retention (edema) from various conditions, and can be used for diabetes insipidus.
Common Side Effects: Frequent urination, dizziness, headache, and weakness are among the most common side effects.
Precautions: Patients should be monitored for electrolyte imbalances and increased sun sensitivity while taking this medication.
Drug Class: It is a thiazide diuretic, distinct from other diuretics like loop diuretics (e.g., Furosemide) in its potency and primary site of action.

Decoding the EP 155 Imprint

The imprint "EP 155" is not a drug name but an identifier found on a peach, round tablet containing hydrochlorothiazide. Pharmaceuticals often have unique alphanumeric codes, or imprints, to help with identification and prevent mix-ups. The "EP" on this pill signifies a specific manufacturer, Leading Pharma, LLC, and the "155" corresponds to details about the tablet.

Hydrochlorothiazide, the active ingredient in the EP 155 tablet, belongs to a class of drugs known as thiazide diuretics. It is a prescription-only medication used for several medical conditions, primarily related to fluid retention and blood pressure control.

How Hydrochlorothiazide (EP 155) Works

Hydrochlorothiazide, the drug identified by the EP 155 imprint, works by acting on the kidneys to increase the excretion of sodium and chloride, and subsequently, water. The mechanism of action occurs in the distal convoluted tubule of the nephron, the functional unit of the kidney. By inhibiting the sodium-chloride symporter in this area, the drug prevents the reabsorption of salt and water back into the bloodstream.

As the body rids itself of excess fluid, several therapeutic effects can be achieved:

Lowering blood pressure: Reduced fluid volume in the blood vessels decreases pressure on the arterial walls, helping to control hypertension.
Reducing edema: The removal of excess fluid from the body's tissues helps alleviate swelling, or edema, in conditions like congestive heart failure, liver disease, and kidney disease.
Treating other conditions: It can also be prescribed to manage other issues, such as nephrocalcinosis and diabetes insipidus, by affecting fluid and electrolyte balance.

Medical Uses for Hydrochlorothiazide (EP 155)

The EP 155 tablet is prescribed to address a variety of medical issues. These include:

High Blood Pressure (Hypertension): Often used alone or in combination with other antihypertensive drugs, hydrochlorothiazide is a foundational medication for managing high blood pressure.
Edema (Fluid Retention): It is effective in treating swelling caused by conditions such as congestive heart failure, severe liver disease (cirrhosis), and kidney dysfunction.
Diabetes Insipidus: In some cases, it can be used to treat this rare condition, which causes the body to produce large amounts of urine.
Kidney Stones: Hydrochlorothiazide can also be used to prevent kidney stones in patients with high levels of calcium in their blood by decreasing the amount of calcium excreted in the urine.

Potential Side Effects and Precautions

Like all medications, hydrochlorothiazide (EP 155) comes with potential side effects. The most common side effects include frequent urination, dizziness, headache, and weakness. However, more serious side effects can occur, and patients should discuss any concerns with a healthcare provider.

Less common but more severe side effects can involve significant changes in electrolyte levels (e.g., low potassium or sodium) and, in rare instances, vision problems or an increased risk of skin cancer from sun exposure. Due to its effect on potassium levels, some patients may need potassium supplements or a modified diet.

Hydrochlorothiazide vs. Furosemide


Feature	Hydrochlorothiazide (EP 155)	Furosemide (Lasix)
Drug Class	Thiazide diuretic	Loop diuretic
Primary Site of Action	Distal convoluted tubule of the kidney	Loop of Henle in the kidney
Onset of Action	Generally takes several hours to reach peak effect	Starts working within a couple of hours and is more rapid-acting
Potency	Considered less potent for diuresis than loop diuretics.	Considered a very potent diuretic for quickly removing excess fluid.
Effect on Blood Pressure	Primary use often includes management of long-term hypertension.	Can treat high blood pressure but is primarily known for treating severe edema.

Conclusion

In summary, the imprint EP 155 identifies a tablet containing hydrochlorothiazide, a diuretic medication used for high blood pressure and fluid retention. While a common and effective prescription, its use requires careful medical supervision, as it can affect electrolyte levels and interact with other drugs. Patients should always consult their doctor or pharmacist to confirm the identity and purpose of any medication based on its imprint code and to understand all potential side effects and precautions. Identifying the correct medication is a critical step in ensuring safe and effective treatment.

For more information on drug identification, the U.S. National Library of Medicine offers a comprehensive resource, DailyMed, which provides official labeling and dosage details for all marketed medications.

Frequently Asked Questions

The tablet with the imprint 'EP 155' is hydrochlorothiazide, which is primarily used to treat high blood pressure and fluid retention, also known as edema.

Hydrochlorothiazide is usually taken orally. To prevent nighttime urination, it's often recommended to take it earlier in the day. Always follow your doctor's instructions and the directions on your prescription label.

Yes, as a diuretic, hydrochlorothiazide can cause a loss of electrolytes such as potassium, magnesium, and sodium. Regular blood tests are often necessary to monitor these levels.

Before taking any other prescription or over-the-counter medications, including NSAIDs, cholesterol-lowering resins, or diabetes medications, you should consult your doctor or pharmacist. Hydrochlorothiazide can have interactions with many other drugs.

Yes, hydrochlorothiazide, identified by the imprint EP 155, is a type of diuretic commonly referred to as a 'water pill' because it helps the body eliminate excess water and salt.

Common side effects include frequent urination, dizziness, headache, and loss of appetite. Less common but serious side effects can involve electrolyte imbalance, vision changes, or increased skin sensitivity to sunlight.

EP 155 (hydrochlorothiazide) is a thiazide diuretic that works in a specific part of the kidney's tubule. It is generally less potent than loop diuretics, such as Furosemide, and is more commonly used for long-term blood pressure management.