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Pharmacology · chapter 35 · Urinary and Bladder Disorder Drugs

Phosphodiesterase 5 Inhibitors

The 13 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. Uses of PDE5 inhibitors

    Phosphodiesterase 5 (PDE5) inhibitors are a class of medications primarily used to treat erectile dysfunction and, in some cases, pulmonary hypertension and benign prostatic hyperplasia (BPH).

  2. Tadalafil approvals

    Tadalafil Tadalafil (Cialis) is the PDE5 inhibitor that has been approved by regulatory agencies to treat both erectile dysfunction and lower urinary tract symptoms associated with BPH.

  3. How tadalafil helps urine flow

    Tadalafil works by relaxing the smooth muscles in the prostate and bladder, which can help improve urine flow and reduce the urinary symptoms caused by prostate enlargement.

  4. Common adverse effects

    Adverse Effects and Contraindications Common adverse effects include headache, dyspepsia, back pain, myalgia, nasal congestion, pain in limbs, flushing, cough, and UTI.

  5. Nitrates are a contraindication

    The drug is contraindicated in clients who are taking nitrates or guanylate cyclase stimulants or who are hypersensitive to the drug or any of its components (DailyMed, Tadalafil, 2023).

  6. Ask about nitrate use

    Before administering the drug, determine the client’s regular or intermittent use of organic nitrates.

  7. Nitrates plus tadalafil

    Concomitant use of these with tadalafil can cause a sudden drop in blood pressure to an unsafe level, resulting in dizziness, syncope, or myocardial infarction (DailyMed, Tadalafil tablet, 2023).

  8. Prolonged erection and priapism

    Monitor for erections lasting longer than 4 hours and for priapism (painful erections lasting longer than 6 hours).

  9. Sudden vision or hearing loss

    Monitor closely for sudden vision or hearing loss because this can be a serious adverse effect of tadalafil.

  10. When to call the provider

    Notify their health care provider if sudden symptoms of vision or hearing loss occur or if they have an erection lasting longer than 4 hours or a painful erection lasting longer than 6 hours.

  11. Get up slowly

    Avoid getting up too fast from a sitting or lying position because this drug may cause a vasomotor response that includes dizziness.

  12. Drugs not to combine

    From the book’s list of what the client should not do:

    Take tadalafil with nitrates, antihypertensives, alpha blockers, or CYP3A4 inhibitors because concomitant use may cause serious adverse effects, such as an unsafe drop in blood pressure, dizziness, and syncope.

  13. Limit alcohol

    From the book’s list of what the client should not do:

    Consume substantial amounts of alcohol with tadalafil due to hypotensive effects.

Terms to know

Priapism
Monitor for erections lasting longer than 4 hours and for priapism (painful erections lasting longer than 6 hours).

Practice questions

Stuck on select-all-that-apply? How to take them one option at a time.

The graded version needs JavaScript. Every question is below anyway, with the answer and why.

Every question here, with the answer

  1. A client with benign prostatic hyperplasia is prescribed tadalafil. Which medication in his history is the priority concern?

    1. Sublingual nitroglycerin as needed for chest pain
    2. Daily multivitamin
    3. A stool softener
    4. Acetaminophen for back pain

    Answer: Sublingual nitroglycerin as needed for chest pain

    Tadalafil is contraindicated with nitrates, including intermittent use, because together they can cause an unsafe drop in blood pressure, syncope or myocardial infarction. The other medications are not listed interactions.

  2. A client taking tadalafil reports sudden loss of vision in one eye. What should the nurse do?

    1. Reassure him that this is a common, harmless effect.
    2. Tell him to take the next dose with food.
    3. Advise him to rest his eyes and recheck next week.
    4. Notify the health care provider promptly.

    Answer: Notify the health care provider promptly.

    Sudden vision or hearing loss can be a serious adverse effect of tadalafil and must be reported. It is not a harmless effect, and waiting delays care.

  3. A nurse is teaching a client who is starting tadalafil for BPH. Which instructions should be included? Select all that apply.

    1. Avoid drinking substantial amounts of alcohol.
    2. Get up slowly from sitting or lying down.
    3. Take it with an alpha blocker to boost the effect.
    4. Do not take it with nitrates.
    5. Report an erection lasting longer than 4 hours.

    Answer: Avoid drinking substantial amounts of alcohol., Get up slowly from sitting or lying down., Do not take it with nitrates., Report an erection lasting longer than 4 hours.

    Clients report erections over 4 hours, limit alcohol because of hypotension, rise slowly, and avoid nitrates. Alpha blockers are also on the list not to combine because of an unsafe drop in blood pressure.

  4. How does tadalafil improve urinary symptoms in a client with BPH?

    1. It increases bladder contractions.
    2. It shrinks the prostate by lowering hormone levels.
    3. It kills bacteria in the urinary tract.
    4. It relaxes smooth muscle in the prostate and bladder.

    Answer: It relaxes smooth muscle in the prostate and bladder.

    Tadalafil relaxes the smooth muscles in the prostate and bladder, improving urine flow. The section does not describe hormone, contraction-boosting or antibacterial effects.

  5. Which findings in a client taking tadalafil should be reported to the provider? Select all that apply.

    1. Sudden hearing loss
    2. Mild nasal congestion
    3. Painful erection lasting longer than 6 hours
    4. Fainting after taking a nitrate
    5. Occasional mild headache

    Answer: Sudden hearing loss, Painful erection lasting longer than 6 hours, Fainting after taking a nitrate

    Priapism, sudden hearing loss and syncope from the nitrate interaction are serious. Nasal congestion and headache are listed as common adverse effects.

  6. A client on tadalafil feels dizzy after standing up quickly. Which explanation should the nurse give?

    1. Dizziness means the dose is too low.
    2. Dizziness only occurs if the drug is taken with food.
    3. Dizziness is caused by a urinary tract infection.
    4. The drug may cause a vasomotor response with dizziness; rise slowly.

    Answer: The drug may cause a vasomotor response with dizziness; rise slowly.

    Tadalafil may cause a vasomotor response that includes dizziness, so clients avoid getting up too fast. The other explanations are not supported.

Where every quote comes from

Section 35.5 Phosphodiesterase 5 Inhibitors 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.