Syndrome of Inappropriate Antidiuretic Hormone Secretion

Medically reviewed by Drugs.com. Last updated on Apr 6, 2025.

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The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition that causes your body to make too much antidiuretic hormone (ADH). ADH is a chemical that helps keep the right balance of fluids in your body. Increased ADH may cause too much water to remain inside your body. Chemicals in your blood, such as salt, may decrease. This may prevent your organs from working properly.

WHILE YOU ARE HERE:

Informed consent

is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.

An IV

is a small tube placed in your vein that is used to give you medicine or liquids.

Intake and output:

Healthcare providers may want to keep track of how much you drink and urinate. They may limit how much you can drink. Ask healthcare providers if they need to measure or collect your urine.

Drugs used to treat this and similar conditions

Medicines:

• ADH antagonists work against the action of ADH to help your body get rid of extra fluids.
• Diuretics help your body get rid of extra fluid through your urine. They are often called water pills.

Tests:

• Blood and urine tests will show levels of salt and other chemicals in your body, and organ function.
• A central venous pressure (CVP) line is an IV inserted into a large blood vessel near your collarbone, neck, or groin. The CVP line is hooked to a monitor. Pressure readings are taken so your healthcare provider can check the amount of fluid in your body.
• A CT , or CAT scan, is a type of x-ray that is taken of your head. The pictures may show the cause of your SIADH. You may be given a dye before the pictures are taken to help healthcare providers see the pictures better. Tell the healthcare provider if you have ever had an allergic reaction to contrast dye.
• A liquid challenge test is used to check how much liquid stays in your body or comes out as urine. You will receive a certain amount of liquid through an IV tube for 24 to 48 hours.

Treatment:

• Salt solutions given slowly through an IV increase the amount of salt in your blood. This corrects the balance of salt in your body and decreases your symptoms.
• You may need to limit the amount of water and other liquids you drink. Your healthcare provider will tell you how much liquid you are allowed to have.

Treatment options

The following list of medications are related to or used in the treatment of this condition.

• demeclocycline
• Vaprisol
• conivaptan

RISKS:

Your brain may swell if the amount of salt in your body is replaced too fast. This may lead to brain damage and cause seizures. Without treatment, you may develop other problems, such as diabetes. Your body may lose too much salt, and brain damage may occur. Life-threatening conditions may develop, such as respiratory arrest or a coma.

CARE AGREEMENT:

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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