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Triamterene and hydrochlorothiazide make up the drug marketed under the name Dyazide. It is a potassium sparing diuretic that is used with thiazide diuretics for edema and hypertension. Medically, it prevents absorption of too much salt and keeps your potassium levels from getting too low. The FDA approved the triamterene/hydrochlorothiazide combination in 1965. For bodybuilding, dyazide is second in popularity to lasix as a pre-contest diuretic.

dyazide chemical structure

Fig 1. Dyazide Chemical Structure

Table of Contents

What is a 'thiazide diuretic'?

Thiazide-like diuretics were first discovered by Merck and Co. in the 1950s, and they are the most affordable antihypertensive drugs available. They work very well at helping lower both systolic and diastolic blood pressure. Essentially, they reduce hypertension by causing diuresis, a fall in plasma volume and a reduction in cardiac output. Also, after chronic use, thiazides cause a reduction in blood pressure by lowering peripheral resistance.

Thiazides are also great for kidney stones. Thiazides lower urinary calcium excretion, making them useful in preventing calcium-containing kidney stones.

dyazide glaxosmithkline

Fig 2. Dyazide GlaxoSmithKline

Medical Uses in Humans and Edema

The two main purposes of dyazide use are hypertension (high blood pressure) and edema. Edema is Greek for "swelling", and is an abnormal accumulation of fluid in the interstitium, located beneath the skin and in the cavities of the body. The main cause of edema is salt retention, which holds excess fluid in the body. In certain liver and kidney diseases, low levels of albumin in the blood can contribute to fluid retention as well.

How it Works

Dyazide works by blocking sodium and water re-absorption in the kidneys; thereby, reducing sodium and water in the body. To make up for the rise in sodium and water in the tubules that will be lost as urine, the kidney tries to reabsorb more sodium and water. It does this by removing potassium from the blood and putting it into the tubules in exchange for sodium and water in the tubules. This causes blood potassium levels to fall.

Triamterene is a diuretic that prevents re-absorption of sodium in exchange for potassium, which reduces sodium and water in the body. It also prevents the depletion of potassium. For this reason, triamterene is called a potassium sparing diuretic. By combining hydrochlorothiazide with triamterene, which makes up the drug Dyazide, sodium and water are eliminated from the body without the loss of potassium.

Half Life

The half life of Dyazide is listed as only 1-2 hours and the active metabolite is 3 hours. However, it is important to remember that half life does not mean the amount of time the drug works in the body; thus, the effects will last up to 8 hours, with the peak effect being 3 hours.

Dosage for medical patients

Dyazide is available in oral only form.

For hypertension and edema patients, the treatment can range from once in the morning with food at 25mgs, up to 75mgs per day. It is not recommended to be taken later in the day, as it will cause the patient to have to wake up at night to urinate frequently.

Bodybuilders and Dosages

Dyazide is used by bodybuilders or physique competitors leading up to competitions or photo shoots, and sometimes up to two days beforehand. It is used to excrete excessive water, so that they appear hard, defined, and have a ripped physique.

Dyazide, like all diuretics, should be used carefully by bodybuilders or it can backfire and be counter productive or even dangerous. The simplest and most popular conservative approach is 12.5mg the night before and the morning of contest, with water sipped the day of competition. If Dyazide is overdosed or timed wrong, the muscles can become small and flat and vascularity will be lost. In addition, it is important to have easy access to a restroom to urinate out the water.

It is not recommended Dyazide be used unless the bodybuilder has at least a few shows under his/her belt to make sure they know how water shedding works naturally.

Side Effects

A powerful diuretic can be very dangerous and the side effects can be serious. The situation is exasperated by the fact that dyazide sticks around for many hours.

If these symptoms begin, medical care may be needed:

  • Dizziness
  • Cramps
  • Vomiting
  • Fainting
  • Circulatory disturbances

Drug Interactions

Cholesterol drugs should not be taken within 4 hours of Dyazide. If you are diabetic, this drug can effect your blood sugar levels.

Trade Names

  • Dyrenium
  • Dyazide
  • Maxzide
  • Triamterene


Want to read about Dyazide on our forums? check out these threads:

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Written by
Steve Smi (Also known as Steve Smith), has over 12 years of experience in the bodybuilding and fitness industry. He's the co-Host of the popular Evolutionary Radio Podcast - over 500,000 listens! He has been a personal trainer and writer for the last 10 years with over 1000 articles written. He's been a moderator on forums for over 10 years. Steve holds the following certifications and records: NASM Personal Trainer NASM Fitness Nutrition Specialist Florida Local Powerlifting champion Top writer for 2019 Fitness rated

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