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35.5 Phosphodiesterase 5 Inhibitors

2 min read•june 18, 2024

are game-changers for managing and . These meds work by relaxing smooth muscles in the prostate and bladder, making it easier to pee and improving sexual function. They're like a magic wand for your plumbing!

While PDE5 inhibitors can be super helpful, they come with some potential side effects. Headaches, flushing, and indigestion are common. It's crucial to avoid taking them with nitrates, as this combo can cause dangerously low blood pressure. Always chat with your doc about any concerns!

Mechanism of Action and Indications

PDE5 inhibitors for BPH

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Top images from around the web for PDE5 inhibitors for BPH

  • Frontiers | Androgen Deficiency and Phosphodiesterase Type 5 Expression Changes in Aging Male ... View original

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  • Frontiers | New Approaches in Oncology for Repositioning Drugs: The Case of PDE5 Inhibitor ... View original

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  • Frontiers | Androgen Deficiency and Phosphodiesterase Type 5 Expression Changes in Aging Male ... View original

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PDE5 inhibitors block PDE5 enzyme which normally breaks down in smooth muscle cells, leading to cGMP accumulation and in the prostate, urethra, and bladder, improving urine flow and reducing BPH symptoms (difficulty urinating, frequent urination, weak urine stream)

PDE5 inhibitor indications, side effects, contraindications

Indications include erectile dysfunction, BPH, and pulmonary hypertension Common side effects are headache, flushing, (indigestion), nasal congestion, back pain, and visual disturbances (blue tinge to vision, increased light sensitivity)
Contraindicated with nitrates (nitroglycerin) due to risk of severe , severe hepatic impairment, recent or stroke within last 6 months, hypotension (BP < 90/50 mmHg), and known hereditary degenerative retinal disorders

Nursing Considerations and Patient Education

Nursing considerations for PDE5 inhibitors

Assess for contraindications before administering by obtaining complete medication history including OTC drugs and herbal supplements Monitor BP before and after administration, withholding medication if BP < 90/50 mmHg Advise patient to take medication as directed with sildenafil and vardenafil on an empty stomach for optimal absorption and with or without food Inform patient of potential side effects and when to seek medical attention Educate patient on proper storage of medication at room temperature away from moisture and heat

Patient education for PDE5 inhibitors

Inform patient of expected onset and duration of action: sildenafil and vardenafil onset 30-60 minutes, duration 4-5 hours; tadalafil onset 30-45 minutes, duration 24-36 hours Advise patient to avoid grapefruit and grapefruit juice while taking PDE5 inhibitors as it can increase drug levels and risk of side effects Instruct patient to seek immediate medical attention for prolonged erection lasting > 4 hours (priapism) Educate patient on lifestyle modifications to manage BPH symptoms such as limiting fluid intake before bedtime, double voiding before bedtime, avoiding caffeine and alcohol, and practicing pelvic floor exercises to improve bladder control Emphasize importance of regular follow-up with healthcare provider to monitor therapy effectiveness and adjust dosage as needed

Key Terms to Review (27)

Amyl Nitrite: Amyl nitrite is a vasodilator medication that works by relaxing and widening blood vessels, which increases blood flow and lowers blood pressure. It is primarily used in the context of phosphodiesterase 5 (PDE5) inhibitors, a class of drugs that treat conditions like erectile dysfunction and pulmonary hypertension.
Benign Prostatic Hyperplasia: Benign prostatic hyperplasia (BPH) is a noncancerous enlargement of the prostate gland, a common condition in older men that can lead to urinary symptoms. This term is relevant in the context of understanding drugs that treat nervous system disorders, antihistamines and decongestants, phosphodiesterase 5 inhibitors, the male reproductive system, and alpha blockers and 5-alpha-reductase inhibitors.
Benign prostatic hyperplasia (BPH): Benign prostatic hyperplasia (BPH) is a non-cancerous enlargement of the prostate gland that commonly affects older men. It can lead to urinary symptoms such as difficulty starting urination and weak urine flow.
BPH: BPH, or Benign Prostatic Hyperplasia, is a noncancerous enlargement of the prostate gland that commonly occurs in older men. This condition can lead to urinary symptoms and is closely related to the topic of Phosphodiesterase 5 Inhibitors, as they are a class of medications used to manage the symptoms associated with BPH.
CGMP: cGMP, or cyclic guanosine monophosphate, is a crucial second messenger molecule that plays a central role in various physiological processes, including the regulation of smooth muscle relaxation, neurotransmission, and cell growth. It is particularly relevant in the context of understanding phosphodiesterase 5 (PDE5) inhibitors, which are a class of drugs that target the cGMP signaling pathway.
Child-Pugh class C: Child-Pugh class C is the most severe classification of liver dysfunction, indicating end-stage liver disease with a high risk of complications and mortality. It is primarily used to assess the prognosis and guide treatment decisions for patients with cirrhosis or other chronic liver conditions.
Cialis: Cialis is a medication used to treat erectile dysfunction (ED) and symptoms of benign prostatic hyperplasia (BPH). It works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), increasing blood flow to certain areas of the body.
Cirrhosis: Cirrhosis is a chronic liver condition characterized by the replacement of healthy liver tissue with scarred, non-functioning tissue. This progressive disease can lead to a variety of complications and is an important consideration in the context of both potassium-sparing diuretics and phosphodiesterase 5 inhibitors.
Creatinine Clearance: Creatinine clearance is a measure of the kidneys' ability to filter and remove creatinine, a waste product generated from the breakdown of muscle tissue, from the blood. It is a widely used indicator of glomerular filtration rate (GFR), which reflects the overall kidney function.
Cyclic guanosine monophosphate: Cyclic guanosine monophosphate (cGMP) is a signaling molecule that plays a crucial role in various physiological processes, including vasodilation, smooth muscle relaxation, and regulation of cellular functions. It is closely associated with the mechanisms of action of nitrates, medications used in heart failure, and phosphodiesterase 5 (PDE5) inhibitors.
Dyspepsia: Dyspepsia, commonly known as indigestion, is a term used to describe a group of symptoms related to the upper digestive tract. It is characterized by discomfort or pain in the upper abdomen, often associated with eating, and can include feelings of fullness, bloating, nausea, and belching.
ED: ED, or erectile dysfunction, is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is a common condition that can have various underlying causes, both physical and psychological, and is an important consideration in the context of phosphodiesterase 5 (PDE5) inhibitors, a class of medications used to treat ED.
Erectile Dysfunction: Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is a common condition that can have physical, psychological, and social implications for men. This term is particularly relevant in the context of topics related to the male reproductive system, phosphodiesterase 5 inhibitors, and the use of androgens, antiandrogens, and anabolic steroids.
Hypotension: Hypotension is a medical condition characterized by an abnormally low blood pressure, where the systolic blood pressure falls below 90 mmHg and the diastolic blood pressure falls below 60 mmHg. This can have significant implications on the body's ability to circulate blood and deliver oxygen and nutrients to vital organs.
Myocardial Infarction: Myocardial infarction, commonly known as a heart attack, is a condition where the blood supply to a part of the heart muscle is suddenly blocked, typically due to a blood clot. This disruption in blood flow can cause damage or death to the affected heart tissue, impairing the heart's ability to pump blood effectively.
Nitric Oxide: Nitric oxide (NO) is a colorless gas that acts as a signaling molecule in the body, playing a crucial role in various physiological processes, including the regulation of blood pressure, cardiac function, and neurotransmission. This versatile molecule has implications in several topics related to cardiovascular and respiratory health.
PAH: PAH, or pulmonary arterial hypertension, is a rare and progressive condition characterized by increased blood pressure in the arteries that carry blood from the heart to the lungs. This elevated pressure can lead to strain on the right side of the heart, ultimately resulting in heart failure if left untreated.
PDE5 inhibitors: PDE5 inhibitors are a class of medications that work by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which is responsible for the breakdown of cyclic guanosine monophosphate (cGMP) in the body. This mechanism of action allows for the accumulation of cGMP, leading to various physiological effects, particularly in the context of erectile dysfunction and pulmonary hypertension.
Penile Erection: Penile erection is a physiological response characterized by the expansion and hardening of the penis, typically due to increased blood flow to the organ. This process is an integral part of the male sexual response cycle and is essential for sexual function and intercourse.
Phosphodiesterase 5 (PDE5) inhibitors: Phosphodiesterase 5 (PDE5) inhibitors are a class of drugs that block the enzyme PDE5, leading to increased blood flow in certain tissues. They are commonly used to treat erectile dysfunction and pulmonary arterial hypertension.
Phosphodiesterase 5 Inhibitors: Phosphodiesterase 5 (PDE5) inhibitors are a class of medications that work by blocking the action of the PDE5 enzyme, which is responsible for the breakdown of cyclic guanosine monophosphate (cGMP) in the body. This mechanism of action allows for the accumulation of cGMP, leading to various physiological effects.
Protein Kinase G: Protein kinase G (PKG) is an enzyme that plays a crucial role in various physiological processes by catalyzing the phosphorylation of specific target proteins. It is a key mediator in the signaling pathways involving the second messenger cyclic guanosine monophosphate (cGMP), which is important for the regulation of smooth muscle relaxation, neurotransmission, and other cellular functions.
Pulmonary Arterial Hypertension: Pulmonary arterial hypertension (PAH) is a chronic and progressive condition characterized by elevated blood pressure in the pulmonary arteries, the blood vessels that carry blood from the heart to the lungs. This increase in pressure can lead to right ventricular hypertrophy, heart failure, and other serious complications if left untreated.
Retinitis Pigmentosa: Retinitis pigmentosa is a group of inherited eye disorders that cause progressive damage to the retina, the light-sensitive tissue at the back of the eye. This damage leads to vision loss, often starting with decreased night vision and peripheral vision, and eventually resulting in tunnel vision and, in some cases, complete blindness.
Smooth Muscle Relaxation: Smooth muscle relaxation refers to the process by which the involuntary, non-striated muscles that line various organs and blood vessels in the body, such as the gastrointestinal tract, urinary bladder, and blood vessels, become less tense or contracted, allowing for improved function and blood flow.
Tadalafil: Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. It increases blood flow by relaxing blood vessels in specific areas of the body.
Vasodilation: Vasodilation refers to the widening or dilation of blood vessels, particularly the arteries and arterioles. This process leads to increased blood flow and reduced vascular resistance, which can have significant implications in various physiological and pharmacological contexts.
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