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Marpres (Generic Hydrochlorothiazide)

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Why is this medication prescribed?

Hydrochlorothiazide is a medication that belongs to the class of diuretics, specifically thiazide diuretics. It is prescribed for the treatment of various medical conditions due to its ability to increase urine production and reduce fluid retention in the body. Here are some common reasons why Hydrochlorothiazide may be prescribed:

  • Hypertension (High Blood Pressure): Hydrochlorothiazide is often used to treat hypertension, as it helps reduce the volume of blood by promoting the excretion of sodium and water through the kidneys. This, in turn, lowers the overall blood pressure.
  • Edema: Edema is the swelling caused by excess fluid retention in the body’s tissues. Hydrochlorothiazide can be prescribed to help reduce edema by increasing the elimination of excess fluid and sodium through urine.
  • Congestive Heart Failure: In some cases of heart failure, where the heart is unable to pump blood effectively, fluid can accumulate in the lungs and other parts of the body. Hydrochlorothiazide may be used to alleviate fluid retention and reduce the workload on the heart.
  • Nephrolithiasis (Kidney Stones): The medication can help reduce the risk of forming certain types of kidney stones by decreasing the concentration of calcium in the urine.
  • Diabetes Insipidus: Hydrochlorothiazide may be used in the treatment of diabetes insipidus, a condition characterized by excessive thirst and dilute urine, by reducing urine volume.
  • Osteoporosis: In some cases, Hydrochlorothiazide is prescribed to reduce calcium excretion, which may help in the prevention of osteoporosis.

How should this medicine be used?

Hydrochlorothiazide should be used exactly as prescribed by a healthcare professional. It is typically taken orally in the form of tablets or capsules. Here are some general guidelines on how to use Hydrochlorothiazide:

  • Dosage: The dosage and frequency of Hydrochlorothiazide will be determined by your doctor based on your medical condition, response to treatment, and other factors. Always follow the prescribed dosage instructions and do not change the dose without consulting your doctor.
  • Timing: Hydrochlorothiazide is usually taken once daily in the morning, as it increases urine production, and taking it later in the day may cause increased nighttime urination, which could disrupt sleep.
  • Swallow Whole: Take the tablet or capsule whole with a glass of water. Do not crush or chew the medication unless specifically instructed by your doctor.
  • Food Interaction: Hydrochlorothiazide can be taken with or without food. However, taking it with food may help reduce stomach upset.
  • Consistency: Try to take Hydrochlorothiazide at the same time each day to maintain a consistent level of the medication in your system.
  • Stay Hydrated: While taking Hydrochlorothiazide, it is essential to stay adequately hydrated. Drink plenty of water to prevent dehydration, especially if you experience increased urination.
  • Duration of Treatment: Follow the prescribed duration of treatment. Do not stop taking Hydrochlorothiazide abruptly unless advised by your doctor, even if you start feeling better. Stopping suddenly can lead to a rebound increase in blood pressure or other health issues.
  • Missed Dose: If you forget to take a dose, take it as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and resume your regular dosing schedule. Do not take a double dose to make up for a missed one.
  • Precautions: Inform your healthcare provider about any other medications, supplements, or medical conditions you have, as there can be potential interactions or contraindications.
  • Regular Check-ups: Regularly visit your doctor for follow-up appointments to monitor your response to Hydrochlorothiazide and make any necessary adjustments to your treatment plan.

Always consult your doctor or pharmacist if you have any questions or concerns about how to use Hydrochlorothiazide properly. Proper usage and adherence to the prescribed regimen are essential for the medication to be effective and safe.

Other uses for this medicine

Apart from the primary uses mentioned earlier, Hydrochlorothiazide is sometimes used off-label for certain medical conditions. Off-label uses of Hydrochlorothiazide may include certain kidney disorders and fluid retention conditions not mentioned in the official prescribing information. However, it’s important to remember that off-label use should only be done under the supervision and prescription of a qualified healthcare professional who has carefully assessed the risks and benefits for the individual patient.

What special precautions should I follow?

Now, let’s discuss some special precautions you should follow when taking Hydrochlorothiazide:

  • Allergies: Inform your doctor if you are allergic to Hydrochlorothiazide or any other medications. Allergic reactions to this drug can be severe and may include rash, itching, swelling, severe dizziness, or difficulty breathing.
  • Medical History: Share your complete medical history with your doctor, especially if you have a history of kidney problems, liver disease, diabetes, gout, asthma or other respiratory disorders, allergies, lupus, or a history of electrolyte imbalances.
  • Pregnancy and Breastfeeding: Hydrochlorothiazide is generally not recommended during pregnancy, especially during the second and third trimesters, as it may harm the developing fetus. It is also excreted in breast milk, so it is not advisable while breastfeeding. Consult your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Interactions: Inform your doctor about all the medications you are currently taking, including prescription drugs, over-the-counter medicines, supplements, and herbal products. Some drugs may interact with Hydrochlorothiazide and cause adverse effects or reduce its effectiveness.
  • Electrolyte Imbalance: Hydrochlorothiazide can cause changes in electrolyte levels, such as low potassium (hypokalemia), low sodium (hyponatremia), and high calcium levels. Your doctor may monitor your electrolyte levels periodically.
  • Dehydration: Make sure to stay well-hydrated while taking Hydrochlorothiazide, especially if you experience increased urination. Dehydration can lead to serious complications.
  • Blood Pressure Monitoring: Regularly check your blood pressure as directed by your doctor. This will help monitor the effectiveness of the medication in managing your hypertension.
  • Diabetes: Hydrochlorothiazide can affect blood sugar levels, so if you have diabetes, monitor your blood glucose regularly and inform your doctor if you notice any significant changes.
  • Surgery: If you are scheduled for surgery, inform your healthcare provider that you are taking Hydrochlorothiazide, as the medication may interact with anesthesia or other medications used during the procedure.
  • Alcohol and Heat: Avoid excessive alcohol consumption and be cautious in hot weather, as Hydrochlorothiazide can increase sensitivity to alcohol and increase the risk of dehydration.

Always follow your doctor’s instructions, and if you experience any concerning side effects or changes in your health while taking Hydrochlorothiazide, contact your healthcare provider promptly.

What special dietary instructions should I follow?

Special Dietary Instructions:

  • Potassium-rich Foods: Hydrochlorothiazide can cause potassium levels to decrease. To counteract this effect, include potassium-rich foods in your diet, such as bananas, oranges, spinach, potatoes, and tomatoes.
  • Sodium Intake: Limit your sodium intake, as hydrochlorothiazide is used to reduce fluid retention and lower blood pressure, and excessive sodium can counteract its effects.
  • Alcohol: Avoid excessive alcohol consumption while on hydrochlorothiazide, as it can increase the risk of dehydration and low blood pressure.

What should I do if I forget a dose?

  • Missed Dose: If you forget to take a dose, take it as soon as you remember, unless it is close to the time for your next dose. In that case, skip the missed dose and resume your regular dosing schedule.
  • Double Dose: Do not take a double dose to make up for a missed one. Taking too much hydrochlorothiazide can lead to adverse effects.

What side effects can this medication cause?

Hydrochlorothiazide, like all medications, can cause side effects in some individuals. Not everyone will experience these side effects, and their severity can vary. Common side effects of Hydrochlorothiazide include:

  • Frequent Urination: Hydrochlorothiazide is a diuretic, and increased urination is a common side effect. This is the desired effect of the medication in treating conditions like hypertension and edema.
  • Dehydration: The increased urination caused by Hydrochlorothiazide can lead to dehydration if adequate fluid intake is not maintained.
  • Electrolyte Imbalance: Hydrochlorothiazide can cause imbalances in electrolytes, such as low potassium (hypokalemia), low sodium (hyponatremia), and high calcium levels.
  • Dizziness or Lightheadedness: Some people may experience dizziness or lightheadedness, especially when standing up quickly from a sitting or lying position.
  • Weakness or Fatigue: Hydrochlorothiazide can cause weakness or fatigue, particularly in cases of significant fluid loss.
  • Headache: Headaches are among the possible side effects of the medication.
  • Nausea or Upset Stomach: Some individuals may experience gastrointestinal symptoms such as nausea or upset stomach.
  • Increased Blood Sugar Levels: Hydrochlorothiazide can, in some cases, raise blood sugar levels, potentially affecting people with diabetes.
  • Skin Reactions: Rarely, Hydrochlorothiazide can cause skin reactions such as rash or photosensitivity (increased sensitivity to sunlight).
  • Gout Flares: In susceptible individuals, Hydrochlorothiazide can trigger or worsen gout attacks.
  • Erectile Dysfunction: Some men may experience difficulties with erection while on Hydrochlorothiazide.
  • Pancreatitis: Although rare, Hydrochlorothiazide has been associated with cases of pancreatitis.

It’s important to note that most people tolerate Hydrochlorothiazide well, and the occurrence of severe side effects is relatively uncommon. If you experience any concerning or persistent side effects while taking the medication, it’s crucial to contact your healthcare provider promptly.

Additionally, some people may be at a higher risk of experiencing certain side effects, especially those with a history of certain medical conditions or taking other medications that may interact with Hydrochlorothiazide. Always inform your doctor about any existing health issues, medications, supplements, or herbal products you are using to ensure safe and effective treatment.

What should I know about storage and disposal of this medication?

Storage and Disposal of Hydrochlorothiazide:


  • Store Hydrochlorothiazide at room temperature, away from direct sunlight and moisture.
  • Keep the medication in its original container with the lid tightly closed.
  • Avoid storing Hydrochlorothiazide in the bathroom, as moisture can degrade the medication.
  • Keep the medication out of reach of children and pets to prevent accidental ingestion.


  • Do not keep expired or unused Hydrochlorothiazide at home. Check the expiration date and discard any outdated medication.
  • Do not flush Hydrochlorothiazide down the toilet or pour it down the drain unless specifically instructed to do so by the local waste management authorities.
  • The best way to dispose of unused medication is through drug take-back programs or community medication disposal sites. You can inquire about these options at your local pharmacy or healthcare facility.

In case of emergency/overdose

  • If you suspect an overdose or experience severe adverse reactions after taking Hydrochlorothiazide, immediately seek medical attention or call your local emergency helpline (e.g., 911 in the United States).
  • Overdosing on Hydrochlorothiazide can lead to dehydration, electrolyte imbalances, and low blood pressure, among other symptoms. It’s essential to receive prompt medical evaluation and management in such situations.

What other information should I know

  • Inform all healthcare providers (doctors, dentists, etc.) about your current use of Hydrochlorothiazide, as it may interact with other medications or medical procedures.
  • Attend regular follow-up appointments with your doctor to monitor your response to the medication and check for any potential side effects or complications.
  • Carry a medical alert card or wear a medical alert bracelet indicating that you are taking Hydrochlorothiazide, especially if you have a medical condition that requires urgent attention (e.g., diabetes).
  • If you are going to have surgery, inform the surgeon and anesthesia provider about your Hydrochlorothiazide use, as it may interact with certain anesthetic drugs.
  • Avoid alcohol while taking Hydrochlorothiazide, as it can exacerbate certain side effects and may interfere with the medication’s effectiveness.

As with any medication, it’s crucial to take Hydrochlorothiazide exactly as prescribed by your healthcare provider. Do not adjust the dosage or stop taking the medication without consulting your doctor, even if you feel better. If you have any questions or concerns about the medication or its use, don’t hesitate to discuss them with your healthcare provider or pharmacist. They can provide you with personalized advice and support to ensure safe and effective treatment.

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