Download Drug interactions

Elimination:
The Urological System and Male
Hormones
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Physiology
• Hormones are natural or synthetic steroidal
compounds that produce the masculinizing and
tissue-building properties of testosterone, the main
male sex hormone.
• Penis has a dermal layer of smooth muscle, under
which is loose connective tissue.
– The parasympathetic system innervates the penile
arteries.
– Normal erection involves the release of nitric oxide,
secondary to sexual stimulation, in the erectile tissue
of the penis.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Physiology (cont.)
• Urethra and prostate: Passing through the penis
is the urethra, which in men transports both
urine and semen.
– The prostate gland is a small, muscular,
rounded organ that encircles the proximal
portion of the urethra as it leaves the urinary
bladder.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Male Urological and Reproductive
Anatomy
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Pathophysiology
• Hormonal problems: deficiency in endogenous sex
hormones causes abnormal sexual development.
• Erectile dysfunction: the inability to achieve or
maintain an erection in at least every three of four
attempts at intercourse
• Benign prostatic hypertrophy (BPH): occurs
spontaneously in men as they age, which results in
an enlargement of the prostate gland
• Prostate cancer: a malignant metastasizing cancer
and the second most common cause of cancer
death in men
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Male Sex Hormones (Androgens)
Prototype drug: Testosterone
Core Drug Knowledge
• Pharmacotherapeutics
– Replacement therapy
• Pharmacokinetics
– High first-pass effect; Highly protein bound
• Pharmacodynamics
– Effects of external testosterone in males are the
same as effects of endogenous testosterone.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Testosterone: Core Drug Knowledge
• Contraindications and precautions
– Serious cardiac, hepatic, or renal disease
• Side effects
– Excessive frequency and duration of penile erections,
and oligospermia (decrease in sperm)
• Adverse effects
– Gynecomastia
– Emotional reactions
• Drug interactions
– Anticoagulants
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Testosterone: Planning and
Interventions
• Maximizing therapeutic effects
– Administer the drug at regular intervals to
maintain therapeutic testosterone levels.
• Minimizing adverse effects
– When prepubescent boys undergo testosterone
therapy, radiographs should be taken every 6
months to assess bone age.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
Testosterone can be used in women with
advanced breast cancer to slow the progression
of the disease.
A. True
B. False
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
Testosterone can be used in women with
advanced breast cancer to slow the progression
of the disease.
A. True
B. False
A. True
Rationale: Testosterone in women slows the growth
of advanced breast cancers, which are estrogen
dependent.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Drugs Used to Treat Erectile Dysfunction
• Agents to treat erectile dysfunction work to
mimic the body’s natural methods of achieving
an erection.
• This drug class is considered the standard firstline therapy for erectile dysfunction.
Prototype drug: sildenafil (Viagra)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Sildenafil: Core Drug Knowledge
• Pharmacotherapeutics
– Used to treat erectile dysfunction
• Pharmacokinetics
– Administered: oral. Metabolism: liver.
Excreted: urine and feces.
• Pharmacodynamics
– This drug is a cGMP-specific
phosphodiesterase type 5 (PDE5) inhibitor.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Sildenafil: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Current use of nitrates (e.g. nitroglycerin)
• Adverse effects
– Facial flushing, headache, nasal congestion,
and heartburn
• Drug interactions
– Drugs metabolized by liver CYP3A4 and
CYP2C9 isoenzymes
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Sildenafil: Teaching, Assessment, and
Evaluation
• Patient and family education
– Drug is not effective without sexual stimulation.
– Administer PRN - 1 hour before sexual activity.
– Inform patients that sexual activity increases the risk
of cardiovascular problems.
• Ongoing assessment and evaluation
– Sildenafil therapy is considered effective if the
patient reports decreased problems with erectile
dysfunction.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
• Sildenafil is contraindicated for which of the
following patients?
A. 80-year-old male with diabetes mellitus
B. 54-year-old male with hypertension
C. 63-year-old male with hyperlipidemia
D. 73-year-old male with history of unstable angina
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
• Sildenafil is contraindicated for which of the
following patients?
D. 73-year-old male with history of unstable angina
Rationale: Sildenafil is contraindicated if the
patient is currently using nitrates because its
vasodilating effects potentiate the hypotensive
effects of nitrates.
This patient would be taking nitrates to treat his
symptoms of unstable angina.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Drugs to Treat Benign Prostatic
Hypertrophy
• Because the prostate gland depends on
dihydrotestosterone (DHT) for growth,
interference with this process is helpful in
reducing prostate size.
Prototype drug: tamsulosin (Flomax)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Tamsulosin: Core Drug Knowledge
• Pharmacotherapeutics
– Treat BPH and androgenetic alopecia (male pattern
baldness)
• Pharmacokinetics
– Administered: oral. Highly protein bound.
Metabolism: liver. Excreted: urine and feces.
• Pharmacodynamics
– Inhibits the steroid 5-alpha reductase and
consequently blocks the peripheral conversion of
testosterone to DHT
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Tamsulosin: Core Drug Knowledge
• Contraindications and precautions
– Women and children
• Side effects
– decreased libido, and decreased volume of
ejaculate
• Adverse effects
– Erectile dysfunction
• Drug interactions
– Decreases PSA levels even in prostate cancer
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
Tamsulosin (Flomax) is used to treat
A. BPH
B. Androgenetic alopecia
C. Pulmonary hypertension
D. Both A and B
E. All of the above
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
Tamsulosin (Flomax) is used to treat
A. BPH
B. Androgenetic alopecia
C. Pulmonary hypertension
D. Both A and B
E. All of the above
D. Both A and B
Rationale: Finasteride is used to treat BPH and
androgenetic alopecia (male pattern baldness).
The dose used for male hair loss is much smaller
than that used for BPH.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Drugs to Treat Male Pattern Baldness
Male pattern baldness may respond to drug therapy.
Prototype drug: minoxidil (Rogaine, Minoxidil)*
• Pharmacotherapeutics
– Used topically to treat androgenetic alopecia
• Pharmacokinetics
– Administered: topically
• Pharmacodynamics
– The exact mode of action for topical minoxidil is
unknown.
* Not on prototype drug list
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Minoxidil: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Hypersensitivity
• Adverse effects
– Irritant dermatitis and allergic contact dermatitis
• Drug interactions
– Topical minoxidil should not be used with other
topical agents.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Anticholinergic Agents
• Anticholinergic drugs affect bladder contraction
because acetylcholine (cholinergic) receptors are
found in the bladder.
• When the receptors are blocked, bladder
contraction cannot occur, and urinary output
decreases.
• Anticholinergics are used to treat overactive
bladder.
Prototype drug: oxybutynin (Ditropan) tolterodine
(Detrol)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Oxybutynin: Core Drug Knowledge
• Pharmacotherapeutics
– Used to treat overactive bladder and incontinence
• Pharmacokinetics
– Administered: oral. Protein bound. Excreted: urine
and stool
• Pharmacodynamics
– Competitive cholinergic muscarinic antagonist
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Oxybutynin : Core Drug Knowledge
(cont.)
• Contraindications and precautions
– Urinary retention, gastric retention, uncontrolled narrowangle glaucoma
• Side effects
– Dry mouth, constipation, abnormal vision, urinary
retention, and xerophthalmia (conjunctival dryness)
• Adverse effects
– Confusion (esp. in the elderly)
• Drug interactions
– Fluoxetine, erythromycin, clarithromycin, and antifungal
agents
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Oxybutynin : Teaching, Assessment, and
Evaluations
• Patient and family education
– Teach signs and symptoms to report.
• Ongoing assessment and evaluation
– Treatment is effective if urinary incontinence and
frequency are decreased and the patient does not
develop serious adverse effects.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
• Patients with renal impairment should receive
half a normally prescribed dose of tolterodine.
A. True
B. False
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Challenge Question
Patients with renal impairment should receive
half a normally prescribed dose of tolterodine.
A. True
B. False
A. True
Rationale: Tolterodine has anticholinergic effects
which can decrease the ability of the bladder to
contract.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Case Study
• Ryan Halstead is a 15-year-old who has been
diagnosed as having low levels of testosterone
with delayed onset of puberty. Six weeks ago, he
started treatment with testosterone (shortacting) at the outpatient center. He returns for his
third visit. Data from the nursing assessment
include the following:
• Vital signs: 124/68, HR-72, RR-16, T-98.4 F
• Height increased by one-half inch
• Beginning to show signs of facial hair growth
• Voice “cracking” occasionally
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Case Study
The patient is currently on testosterone, 50 mg
IM q 2 weeks.
1. Which of the findings from the nursing
assessment demonstrate the effectiveness of
drug therapy?
2. Which of the findings from the nursing
assessment would demonstrate side or
adverse effects from drug therapy?
3. What teaching is required for Ryan regarding
his drug therapy?
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins