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Pharmacology · chapter 26 · Hypothalamus, Pituitary, and Adrenal Disorder Drugs

Antidiuretic Hormones

The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.

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Key points

  1. How ADH reduces urine output

    When ADH is released, it causes the kidneys to retain water, which leads to an increase in blood volume and a decrease in urine output.

  2. Too little ADH: diabetes insipidus

    In conditions where there is a deficiency or dysfunction of ADH, such as diabetes insipidus, excessive urine output can occur, leading to dehydration, electrolyte imbalances, and manifestations of polydipsia and hypotonic polyuria (Christ-Crain Gaisl, 2021).

  3. Too much ADH: SIADH

    Conversely, an excess of ADH production can cause water retention and low sodium levels as with syndrome of inappropriate antidiuretic hormone (SIADH). Excess ADH can result in manifestations of symptomatic hyponatremia, such as muscle cramps, nausea, and vomiting (Mentrasti et al., 2020; Yasir Mechanic, 2023).

  4. Uses of desmopressin

    Desmopressin is commonly used to treat diabetes insipidus, nocturnal enuresis (bed wetting), and bleeding disorders such as hemophilia A.

  5. Desmopressin adverse effects and contraindications

    Adverse effects include headache, nausea, and low sodium levels. It is contraindicated in clients with severe renal impairment, a history of hyponatremia, or hypersensitivity.

  6. Vasopressin raises blood pressure

    Vasopressin also has vasoconstrictor effects, causing narrowing of blood vessels and an increase in blood pressure, making it useful as a drug to treat conditions such as shock or cardiac arrest.

  7. Demeclocycline for SIADH

    This drug interferes with vasopressin and is used to treat SIADH. It helps to regulate water balance, leading to an increase in urine output and a reduction in the amount of water in the body.

  8. Start tolvaptan in hospital

    Tolvaptan should be initiated and re-initiated in a hospital setting where serum sodium levels can be monitored closely. A too rapid correction of hyponatremia can cause osmotic demyelination, resulting in seizures, coma, and death.

  9. Common ADH drug adverse effects

    Typical adverse effects of ADH drug classification include fluid retention and hyponatremia—by reducing urine output, which can lead to fluid retention and low sodium levels—headache, and gastrointestinal symptoms such as abdominal cramps, nausea, and vomiting.

  10. Risk in cardiovascular disease

    With cardiovascular disease, ADH drugs can cause vasoconstriction, which can worsen angina, elevate blood pressure, and promote fluid retention that can exacerbate heart failure and lead to fluid volume overload.

  11. Intake, output and sodium

    Monitor client fluid intake and urine output closely. Monitor electrolytes, especially sodium, as well as urine specific gravity.

  12. Nasal route check

    Monitor nasal passages for ulceration if administering via nasal route.

  13. Improvement can take weeks

    Keep a journal of their symptoms. It may take several weeks for them to notice improved symptoms.

  14. Black box warnings

    Desmopressin acetate may precipitate hyponatremia, which may be life-threatening if severe. Tolvaptan can cause serious and potentially fatal liver injury.

Terms to know

Desmopressin acetate
Desmopressin acetate is a synthetic ADH that regulates water balance and blood pressure by promoting water retention in the kidneys and reducing the amount of urine produced.
Demeclocycline
Demeclocycline is a tetracycline antibiotic that is rarely used for its antibiotic properties.
Tolvaptan
Tolvaptan is used to treat a condition called hyponatremia (low serum sodium levels).

Practice questions

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  1. A client with diabetes insipidus is started on desmopressin. Which finding shows the drug is working?

    1. Thirst increases
    2. Serum sodium falls sharply
    3. Urine output decreases
    4. Urine output increases

    Answer: Urine output decreases

    Desmopressin is a synthetic ADH that promotes water retention and reduces urine produced, correcting the excessive urine of diabetes insipidus. Rising output or thirst means it is not working, and a sharp sodium drop is an adverse effect.

  2. A client on desmopressin develops headache, nausea, muscle cramps, and new confusion. What should the nurse suspect?

    1. Hypoglycemia
    2. Water intoxication with low sodium
    3. An expected response to the first dose
    4. Dehydration from undertreatment

    Answer: Water intoxication with low sodium

    ADH drugs reduce urine output and can cause fluid retention and hyponatremia; nausea, headache, mental status changes, and muscle cramps are signs of water intoxication. Dehydration would bring extreme thirst and dry mouth.

  3. A client with SIADH and severe hyponatremia has an order to start tolvaptan. Where should the drug be started?

    1. Anywhere, because sodium correction speed does not matter
    2. At an outpatient pharmacy
    3. In the hospital, where serum sodium can be monitored closely
    4. At home with weekly lab checks

    Answer: In the hospital, where serum sodium can be monitored closely

    Tolvaptan should be started in a hospital where serum sodium can be monitored closely, because too rapid correction of hyponatremia can cause osmotic demyelination. The other settings lack close monitoring.

  4. A nurse is caring for a client receiving an ADH drug. Which actions are appropriate? Select all that apply.

    1. Check urine specific gravity.
    2. Inspect the nasal passages for ulceration if given intranasally.
    3. Monitor serum sodium.
    4. Monitor fluid intake and urine output closely.
    5. Encourage unlimited fluid intake.

    Answer: Check urine specific gravity., Inspect the nasal passages for ulceration if given intranasally., Monitor serum sodium., Monitor fluid intake and urine output closely.

    The nurse monitors intake and output, sodium, and urine specific gravity, and checks the nose for ulceration with nasal dosing. Because ADH drugs cause water retention, unlimited fluids risk water intoxication.

  5. Which client conditions are contraindications or major concerns for ADH drugs? Select all that apply.

    1. Angina
    2. Kidney disease
    3. Diabetes insipidus
    4. Hyponatremia
    5. Heart failure

    Answer: Angina, Kidney disease, Hyponatremia, Heart failure

    ADH drugs can worsen hyponatremia, cause vasoconstriction that worsens angina and fluid retention that worsens heart failure, and further impair renal function. Diabetes insipidus is what these drugs treat.

  6. A client with SIADH is prescribed demeclocycline. Which effect should the nurse expect?

    1. Increased urine output
    2. Increased blood clotting
    3. Decreased urine output
    4. Higher blood pressure from vasoconstriction

    Answer: Increased urine output

    Demeclocycline interferes with vasopressin, increasing urine output and reducing body water in SIADH. Decreased output, clotting, and vasoconstriction describe ADH drugs such as desmopressin and vasopressin.

Where every quote comes from

Section 26.3 Antidiuretic Hormones of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.

The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.