Pharmacology

Sexual Dysfunction-Erectile Dysfunction

Case Study

Patient Profile

Name: Alexander

Age: 55 years old

Gender: male

Current Medications

Lisinopril, atorvastatin

History of Present Illness

Alexander is a 55-year-old man with a history of hypertension on angiotensin converting enzyme inhibitor and hypercholesterolemia for which he is currently on statin therapy. He is presenting for quarterly routine follow-up. Today he expresses concern about his inability to perform sexually which has been going on for some time now. He has finally decided he needs to ask for help. He notes that his ability to achieve an erection sufficient for intercourse just isn’t there any longer. He is feeling a bit down about this.

Relevant Assessment

Denies history of myocardial infarction, heart failure, or stroke.

Social History: Previous smoker; quit five years ago. Drinks “socially;” occasionally has one or two beers.

Physical Examination: Blood pressure is at goal; body mass index is 30 kg/m2.

No other expanded review of system (subjective data) or examination (objective data) has an impact on the diagnosis reviewed in this case.

Differentials

Vascular erectile dysfunction, neurogenic erectile dysfunction, hormonal erectile dysfunction, psychogenic erectile dysfunction, medication induced erectile dysfunction, lifestyle induced erectile dysfunction (smoking, alcohol, obesity), erectile dysfunction secondary to medical conditions (diabetes, hypertension, renal disease)

Diagnosis

Vascular erectile dysfunction

Diagnostic Testing

Lipid panel

Referrals

None at this time

Patient/Provider Collaborative Goals

Alexander will experience improvement in sexual function and ability to achieve and maintain sufficient erection for sexual intercourse as desired by time of planned follow-up.

Therapeutic Interventions

  1. Describe a first-line pharmacologic treatment: Include drug name, dose and formulation, frequency, and length of treatment at this dose.
    Answer:

    One option is sildenafil (Viagra) 50 mg tablet once daily as needed one hour before sexual activity; may be taken up to four hours before sexual activity.

    • Drug Mechanism of Action:
      Answer:

      Sildenafil (Viagra) is a phosphodiesterase type 5 (PDE-5) inhibitor. By inhibiting PDE-5, there is breakdown of cyclic guanosine monophosphate (cGMP) in the corpus cavernosum augmenting the effect of nitrous oxide released with sexual stimulation increasing smooth muscle relaxation and influx of blood to the area supporting erection.

    • Contraindications if applicable:
      Answer:

      Hypersensitivity to sildenafil or any of the formulation’s components. Concurrent use of nitrates, including nitroglycerin, routinely or intermittently. Additionally, concurrent use of riociguat, a guanylate cyclase stimulator used for pulmonary artery hypertension, is a contraindication to sildenafil (Viagra).

  1. Therapeutic advisement and monitoring: (include any specific instructions that apply, such as when to take the medication, if there are foods to avoid, storage issues, etc; include what laboratory/other (i.e., EKG) test monitoring to expect and how often and monitoring for adverse effects both common and serious)
    Answer:

    Specific Instructions: Instruct the patient to take sildenafil (Viagra) one hour prior to sexual activity. Inform patients that it is extremely dangerous to take nitrates with sildenafil (Viagra). If a patient is having chest pain after having taken sildenafil (Viagra) and EMS is called, patients or family members should notify EMS immediately of the last time and dose the sildenafil (Viagra) was taken. EMS will not administer the nitrate for at least 24 hours from the sildenafil (Viagra) ingestion. If the patient has been treated with nitrates, they must delay sildenafil (Viagra) use by at least 24 hours. Educate patients to avoid other medications or substances that may reduce blood pressure, including THC or alcohol. Instruct patients to inform all health care providers that sildenafil (Viagra) is one of their medications to avoid potential drug-drug interactions. For example, alpha blockers used for prostate conditions combined with sildenafil (Viagra) may lead to unsafe lowering of blood pressure. Advise patients with some preexisting retinal conditions that sildenafil (Viagra) is contraindicated. Instruct patients to avoid the consumption of grapefruit juice.

    Patients should also be advised to report any serious adverse effects listed below.

    • Therapeutic Monitoring: The nurse practitioner should monitor blood pressure and heart rate when sildenafil (Viagra) is used concurrently with medications that may lower blood pressure. Additionally, the NP should maintain an index of suspicion for pulmonary edema being alert to symptoms or signs such as dyspnea, shortness of breath, coughing up frothy, pink or blood-tinged sputum, and wheezing, anxiety, restlessness, cold and clammy skin, and tachycardia, irregular heartbeat.
    • Monitor Side/Adverse Effects: The most common side/adverse effects are facial flushing, diarrhea, dyspepsia, headache, myalgia, visual disturbances, and epistaxis.
    • Serious Adverse Effects:
      • Hearing Loss: Sudden onset of hearing impairment or loss associated with or without tinnitus or dizziness has been noted with the use of sildenafil (Viagra).
      • Hypotension: Decrease in systolic blood pressure up to 10 mmHg and decrease in diastolic blood pressure up to 7 mmHg have been observed; these effects dissipate within about six hours. Patients should be made aware of this change in case they are symptomatic with lightheadedness or dizziness and instructed to sit or lay down to avoid injuries related to falls.
      • Priapism: If the patient experiences priapism of four hours or longer, they should be instructed to go to the emergency department immediately for evaluation and treatment to avoid permanent damage to penile tissue.
      • Visual Disturbances: Changes in color vision, blue/green lack of discrimination, photophobia, and blurry vision. These conditions may resolve as the medication effects wear off. Emergency ocular conditions requiring immediate ophthalmologic evaluation include anterior ischemic optic neuropathy, anterior uveitis, macular edema, and retinal artery occlusion.
  1. Planned follow-up should consider adverse effect monitoring, dose adjustment considerations, and decisions about continuing versus discontinuing. In this case, planned follow-up would be:
    Answer:

    Follow-up office visit in one month to evaluate efficacy of treatment and presence or absence of side/adverse effects.

Review Questions

Click the arrow to expand the section and view the correct answers.

  1. Which medication class is LEAST likely to cause erectile dysfunction?
    1. Beta blocker
    2. Angiotensin converting enzyme inhibitor
    3. Selective serotonin reuptake inhibitor
    4. Antipsychotics
Answer:

B. Angiotensin converting enzyme inhibitor

Feedback: The following drug classes are known to cause sexual/erectile dysfunction: Cardia glycosides, central alpha-adrenergic agonists, beta blockers, thiazide diuretics, aldosterone antagonists, selective serotonin reuptake inhibitors (SSRI), monoamine oxidase inhibitors, tricyclic antidepressants, antipsychotics, mood stabilizers, alcohol, and 5-alpha-reductase inhibitors. Of the SSRIs, paroxetine (Paxil) is said to have the highest risk of causing erectile dysfunction.

  1. Alcohol use can improve erectile dysfunction, and moderate drinking should be encouraged to help patients with erectile dysfunction. (True or False)
    1. True
    2. False
Answer:

B. False

Feedback: Alcohol use can be the cause of erectile dysfunction; decreasing alcohol consumption can help patients with erectile dysfunction.

  1. Which statement about the treatment of erectile dysfunction is accurate?
    1. Per the American Urological Association (2018), sildenafil is the only first-line treatment for erectile dysfunction.
    2. Per the American Urological Association (2018), flibanserin is the only first-line treatment for erectile dysfunction.
    3. Per the American Urological Association (2018), bremelanotide is the only first-line treatment for erectile dysfunction.
    4. Per the American Urological Association (2018), invasive/surgical and medication treatment are both acceptable as first-line treatment for erectile dysfunction.
Answer:

D. Per the American Urological Association (2018), invasive/surgical and medication treatment are both acceptable as first-line treatment for erectile dysfunction.

Feedback: Per the American Urological Association (2018), invasive/surgical and medication treatment are both acceptable as first-line treatment for erectile dysfunction. The choice of treatment is based upon a thorough review of the risks and benefits of each option. Remember that good prescribing/safe prescribing means knowing when it is appropriate as well as not appropriate to prescribe medication therapy.

  1. Which class of oral medication is used to treat erectile dysfunction?
    1. Phosphodiesterase (PDE)-5 inhibitors
    2. 5-hydroxytryptophan (5-HTP)
    3. Cytochrome P450 (CYP) 3A4 inhibitors
    4. Cytochrome P450 (CYP) 2D6 inhibitors
Answer:

A. Phosphodiesterase (PDE)-5 inhibitors

Feedback: Medication treatment options include Phosphodiesterase (PDE)-5 inhibitors. Examples include: Avanafil (Stendra), sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra). There are medications that are administered via the intracavernosal root; these medications include prostaglandin E1 drugs. Examples of prostaglandin E1 are alprostadil (Caver jet) and alprostadil intraurethral (Muse).

  1. Which patient are phosphodiesterase (PDE)-5 inhibitors contraindicated for?
    1. A 40-year-old male with a history of hyperlipidemia on statin therapy.
    2. A 35-year-old male with a history of hypertension on hydrochlorothiazide.
    3. A 65-year-old male with a history of myocardial infarction and angina who uses nitroglycerine sublingually.
    4. A 42-year-old diabetic with a hemoglobin A1c of less than 7.0 millimoles per mole.
Answer:

C. A 65-year-old male with a history of myocardial infarction and angina who uses nitroglycerine sublingually.

Feedback: Concurrent use of nitrates (nitroglycerine) and phosphodiesterase five inhibitors (PDE-5 inhibitors) is contraindicated due to risk of dangerously lowering blood pressure. Nitroglycerine must be separated from nitrates by a minimum of 24 hours. It is important to ask patients that you may be considering treating chest pain or unstable angina with nitrates if they use any of the PDE-5 inhibitors and ask when they last used them before administering nitrates.

  1. An adverse effect of phosphodiesterase five inhibitors therapy is priapism. Priapism lasting more than ___ hour(s) requires emergency evaluation and intervention?
    1. One
    2. Two
    3. Three
    4. Four
Answer:

D. Four

Feedback: A potentially dangerous adverse effect of phosphodiesterase five inhibitors (PDE-5 inhibitors) is priapism. Priapism is a painful erection that lasts greater than four hours and requires emergency evaluation and intervention to avoid permanent damage to penile tissues. If the priapism exceeds 24 hours, the patient may not ever regain sexual function. The corpus cavernosum must be drained, irrigated, then injected with a vasoconstricting medication.

  1. Drugs used to treat female sexual interest-arousal disorder include which of the following?
    1. Phosphodiesterase five inhibitors (PDE-5 inhibitors)
    2. 5-hydroxytryptophan (5-HTP)
    3. Mixed 5-HT agonist/5-HT2A antagonists
    4. HT2A antagonists
Answer:

C. Mixed 5-HT agonist/5-HT2A antagonists

Feedback: Medication used to treat female sexual interest-arousal disorder include the mixed 5-HT agonist/5-HT2A antagonist, flibanserin (Addyi), and the melanocortin receptor agonist bremelanotide (Vyleesi).

  1. Flibanserin (Addyi) is used for female sexual interest-arousal disorder. This medication does not have any Food and Drug Administration warnings; therefore, it is safe for everyone. (True or False)
    1. True
    2. False
Answer:

B. False

Feedback: Flibanserin (Addyi) is Food and Drug Administration (FDA)-approved for female sexual interest-arousal disorder and is not FDA-approved for use by men. This medication has a FDA warning that as little as one or two alcoholic beverages can lead to significant and dangerous hypotension and syncope. Flibanserin (Addyi) is absolutely contraindicated if three or more alcoholic beverages have been ingested.

References

Burnett, A. L., Nehra, A., Breau, R. H., Culkin, D. J., Faraday, M. M., Hakim, L. S., Heidelbaugh, J., Khera, M., McVary, K. T., Miner, M. M., Nelson, C. J., Sadeghi-Nejad, H., Seftel, A. D., & Shindel, A. W. (2018). Erectile dysfunction: AUA guideline. Journal of Urology, 200(3), 633–641. https://doi.org/10.1016/j.juro.2018.05.004

Condina Leik, M. T. (2025). Male reproductive system review. In FNP Certification Intensive Review (pp. 161–194). Springer Publishing.

Khera, M. (2025). Treatment of male sexual dysfunction. Up To Date®. Retrieved June 12, 2025 from https://www.uptodate.com/contents/treatment-of-male-sexual-dysfunction

Rosenthal, L. D., & Burchum, J. R. (2026). Drugs for sexual dysfunction. In Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (3rd ed., pp. 457–465). Elsevier.

Up To Date. (2025). Sildenafil: Drug information. Lexidrug. Retrieved June 12, 2025 from https://www.uptodate.com/contents/sildenafil-drug-information

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Be Prepared for Your Nurse Practitioner Clinical Readiness Exam Copyright © 2026 by Elizabeth Heavey, Renee Biedlingmaier, Colleen Burgoyne and Carnel C. Jackson is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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