Preeclampsia high BP

Last Updated December 20th, 2021

Therapeutic Indications

Hydrochlorothiazide is a thiazide diuretic. A diuretic is a prescription pill that seeks to improve the number of fluids and salt ejected from the body as urine. Hydrochlorothiazide is available both in generic form as well as under the brand-name, Microzide.

This medicine can be used in isolation or also as a combination along with other drugs to effectively control hypertension. The drug is manufactured as a tablet, solution and capsule form. It effectively combats fluid retention in the body that may arise due to cirrhosis, kidney problems or heart disease. Use of corticosteroids can also cause fluid retention in the body which this drug efficiently seeks to treat.

This class of drugs called thiazide diuretic focuses on removing excess salt and water from the body by enhancing the flow of urine. This reduces the load on the heart (in the presence of excess salt, the heart has to work harder to pump blood)and helps keep blood pressure levels in check. The drug offsets the risk of inflammation. Symptoms such as shortness of breath and swelling in the feet and ankles also reduce with this drug.

Do I Need A Prescription?

Hydrochlorothiazide is a prescription-only medicine.


Dosage for hydrochlorothiazide is dependent on the medical condition, severity, and response to the drug. The dose is also fixed after considering the presence of other medical conditions as well as medicines being consumed. Age and health condition of the patient are also key factors that help the healthcare professional decide on dosage. Special care is to be taken for pediatrics and geriatrics while fixing the dosage.

It is also good to have regular follow-ups while on this medication as the healthcare professional can evaluate if the drug is working well or if the dose needs to be altered

Forms and strengths

  • Both generic Hydrochlorothiazide and Microzide oral tablets are available in strengths of 12.5 mg, 25 mg, and 50 mg.
  • The drug is best when stored at room temperature in a closed container away from moisture, light, and heat.

Dosage for high blood pressure


Adult dosage (ages 18 to 64 years) and child dosage (ages 12 to 17 years)

The dosage for adults begins with 25 mg taken orally once a day. The dose could be increased to 50 mg per day in case there is no improvement after the initial dose.

Child dosage (ages 3 to 11 years)

The dosage for children this age group begins with 0.5 to 1 mg per pound per day, which can be administered as a single dose or two doses. Care should be taken that the dosage per day should not be more than 100 mg.

Child dosage (ages 6 months to 2 years)

The dosage for this age group of children begins with 0.5 to 1 mg per pound per day and can be consumed as one single dose or two doses. 37.5 mg is the maximum dose permitted for this age group of children.

Child dosage (ages 0 to 6 months)

For babies, the dosage is fixed at 1.5 mg per pound per day, taken orally and administered as two divided doses.

Senior dosage (ages 65 years and older)

Dosage for senior adults is much lesser than that of younger adults. This is because senior adults process this drug much slower, therefore the dosage is fixed at a lower strength and a different schedule.

Dosage for edema

Adult dosage (ages 18 to 64 years) and child dosage (ages 12 to 17 years)

A dosage of 25mg to 100 mg of hydrochlorothiazide is prescribed each day as a single or divided dose. It is crucial to keep the electrolyte level in check, so specialists recommend taking the drug three to five days a week.

Child dosage (ages 3 to 11 years)

The dose is fixed at 0.5 to 1 mg per pound per day to be consumed as a single dose or two divided doses. The dosage per day should not exceed 100 mg.

Child dosage (ages 6 months to 2 years)

The dosage is fixed at 0.5 to 1 mg per pound per day, taken as a single dose or two divided doses without crossing the limit of 37.5 mg per day. For children between 0 to 6 months of age, the dosage is up to 1.5 mg per pound per day consumed as two divided doses.

Senior dosage (ages 65 years and older): Healthcare providers fix the dose on  a case to case basis keeping in mind the age factor and that older adults tend to process the drugs slowly.


It is imperative to take hydrochlorothiazide as prescribed. The drug is used in the long term and the risks are high if treatment schedules and dosages are not followed. The risk of high blood pressure and complications of heart attack and stroke loom large in the absence of not taking the drug. Taking it on schedule and as per the prescription is vital for the efficacy of the drug.

Chemical composition

Hydrochlorothiazide appears as a white crystalline powder and contains colloidal silicon dioxide, magnesium stearate, pregelatinized starch, gelatin, titanium dioxide, sodium lauryl sulfate, microcrystalline cellulose, and black iron oxide.

Mechanism of action

Preeclampsia high BPHydrochlorothiazide works on high blood pressure and reduces the swelling caused by liver damage, or heart failure. Intake of certain medications like estrogens and corticosteroids can cause swelling of the ankles and limbs.

Used alone or in combination with other drugs, hydrochlorothiazide is a diuretic. Also known as a water pill, this drug focuses on ejecting excess salt from the body. It helps the heart pump blood without struggle and lowers blood pressure as well as a collection of fluid in the body. The drug improves urine output by mainly impeding salt and disallowing fluid reabsorption.


Drug interactions are a reality, therefore, before starting these drugs it is crucial to be aware of how hydrochlorothiazide may interact with other medicines or influence the presence of medical disease/conditions.

Pediatric: Dosage for children needs to be handled very carefully as the drug can have long term side effects. The safety and efficacy of this drug for pediatric populations need more research and study.

Presence of allergies: Discuss with your health care provider about the presence of allergies. This information is crucial so that the specialist is in a position to advise correctly.

Geriatric: Senior adults may portray age-associated kidney, liver and heart problems which may necessitate the adjustment of dosage of hydrochlorothiazide.  Caution needs to be exercised while prescribing this drug for the senior lot.

Pregnancy: Experiments on animals have shown that the drug hydrochlorothiazide may not adversely affect the fetus. There is a need for more research in this area on humans to be absolutely sure of the safety of this drug during pregnancy.

Breastfeeding: Breastfeeding women on the drug can convey substantial amounts of the drug through the breast milk to the baby which can lead to side effects. It is better to talk to the healthcare provider and the weigh the risks and benefits of taking this medicine.

Facts on hydrochlorothiazide

  • High blood pressure is a silent killer. This is because, untreated blood pressure damages the blood vessels of the kidney, brain, and heart, which can lead to complications such as kidney failure, heart attack, and stroke.
  • A  senior research chemist with Ciba Pharmaceutical discovered two diuretics, hydrochlorothiazide, and Cyclopenthiazide in 1955.
  • Hydrochlorothiazide is unsurprisingly the most popularly recommended diuretic to treat high blood pressure.
  • Since 1958, Ciba-Geigy has been distributing hydrochlorothiazide with the brand name Esidrix.

Drug Interactions

The possibility of interaction of Hydrochlorothiazide with other medications is a reality and needs to be weighed consciously. Talk to the yourhealthcare provider and gauge the risks before taking this medication. Caution is needed regarding interaction with beta-blockers. The following drugs interact with hydrochlorothiazide.

  • Bisoprolol
  • Metoprolol
  • Atenolol

Hydrochlorothiazide, when taken along with diabetes drugs, can lead to elevated blood sugar levels. For this reason, the specialist increases the dosage of diabetic medications. Those on insulin and oral tablets such as pioglitazone, exenatide, metformin, glimepiride, and sitagliptin must be aware of the interactions with hydrochlorothiazide.

Do not take hydrochlorothiazide along with other blood pressure medications. This could make the blood pressure drop to very low levels putting you at a major health risk. The other blood pressure medications with the potential to interact with hydrochlorothiazide are:

  • Candesartan
  • Enalapril
  • Fosinopril
  • Lisinopril
  • Valsartan
  • Losartan
  • Primidone
  • Phenobarbital
  • Pentobarbital

Cholesterol drugs could render hydrochlorothiazide ineffective. Some of the drugs that interact with hydrochlorothiazide are:

  • Cholestyramine
  • Colestipol

Narcotics and hydrochlorothiazide combo can abnormally lower blood sugar levels. Therefore, drugs such as codeine and morphine interact with this medicine.

Drug interactions with Corticosteroids such as methylprednisolone and prednisone can reduce electrolyte levels in the body and cause huge problems.

Further, painkillers and Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the effectiveness of hydrochlorothiazide.

Hydrochlorothiazide can trigger an acute allergic reaction. Allergic symptoms such as inflammation of throat or tongue, hives or any trouble breathing should not be ignored as it could be a reaction to this drug. The warning is indicated for those allergic to sulphonamide. Such people should completely avoid hydrochlorothiazide as the side effects could be life-threatening.

Alcohol consumption while taking hydrochlorothiazide can cause blood pressure to drop too low. This could manifest as symptoms of dizziness.

Caution in the presence of following health conditions

  • Victims of kidney problems should exercise caution while taking this drug. Poor kidney function causes drug accumulation in the body as the kidney is unable to throw out excessive salt from the body. When kidneys do not work properly, it could cause a build-up of the drugs in the body, resulting in side-effects.
  • The warning is also indicated for those with poor liver function. Hydrochlorothiazide can trigger an imbalance in electrolytes and fluids which can cause the liver to get worse, this is why doctors must keep a track of fluid and electrolytes.
  • Symptoms of electrolyte imbalance could show up as weakness, fatigue, dry mouth, thirst, agitation, restlessness, and mental confusion. In extreme cases, seizures can also occur.
  • Those with lupus may experience an increase in symptoms with Hydrochlorothiazide

Side effects

Those taking hydrochlorothiazide may experience the following symptoms. The following symptoms occur commonly and are not worrisome if it goes away in a few days or weeks.

  • Weakness
  • Headache
  • Dizziness
  • Low BP especially when standing up or sitting down
  • Tingling in the limbs
  • Erectile dysfunction

Serious side effects

The following serious side effects merit an emergency consultation with the medical specialist.

  • Kidney failure
  • Abnormal heart rate
  • Extreme fatigue
  • Skin rash that turns painful
  • Mouth sores
  • Breathlessness
  • Chest pain
  • Reduced urine output
  • Swelling in the feet and ankles
  • Blurred vision
  • Mental confusion

What to do if you skip a dose

Skipping a dose is no worry as long as you do not make a habit of it. Take the dose as soon as it comes to your mind. In case it is very close to the next dose, then take only one dose at that time. It is not good to take two doses close to each other. The side effects could prove costly.


An overdose of hydrochlorothiazide can cause the blood pressure to drop to abysmal levels which might make you feel dizzy and faint. In case of severe symptoms, it is best to contact emergency medical assistance.

Substitutes for the drug

Hydrochlorothiazide has the following substitute drugs

  • Lasix
  • Thalitone
  • Aldactone
  • Edecrin

Generic Brand Names of Hydrochlorothiazide

Hydrochlorothiazide is the generic form. The brand name of this drug is Microzide. Hydrochlorothiazide is available as a generic drug and also under different brand names. Some of the brand names of this drug are Microzide, HydroDIURIL, Esidrix, Oretic.

Different Brands and Manufacturing Companies of the drug

Generic Hydrochlorothiazide is manufactured by 5 companies. Some of the brand names of this medicine are listed below

  • Klorzide (25mg) – Zydus Cadila Healthcare Ltd
  • Bpzide – Stadmed Pvt. Ltd.
  • Xenia (12.5mg) US Vitamins Limited
  • Hydride Micro Labs Ltd (Cardicare)
  • Aquazide Sun Pharmaceuticals Industries Ltd.


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