Pharmacologic Therapy PDF

10/19/23, 3:39 AM Realizeit for Student Pharmacologic Therapy Pharmacologic therapy works best when used as an adjunct to behavioral interventions. The particular antibiotic used will be dependent on the type of incontinence diagnosed (AUA, 2019a). Anticholinergic agents inhibit bladder contractio...

10/19/23, 3:39 AM Realizeit for Student Pharmacologic Therapy Pharmacologic therapy works best when used as an adjunct to behavioral interventions. The particular antibiotic used will be dependent on the type of incontinence diagnosed (AUA, 2019a). Anticholinergic agents inhibit bladder contraction and are considered first-line medications for urge incontinence (AUA, 2019a; Wooldridge, 2017). Mirabegron, a beta-3 adrenergic agonist, may be used for urge incontinence and overactive bladder but should be used with caution in patients with hypertension as it can cause increased blood pressure (Wooldridge, 2017). A tricyclic antidepressant medication (e.g., amitriptyline) can also decrease bladder contractions as well as increase bladder neck resistance (Wooldridge, 2017). Pseudoephedrine sulfate, which acts on alpha-adrenergic receptors, causing urinary retention, may be used to treat stress incontinence; it needs to be used with caution in men with prostatic hyperplasia and in patients with hypertension. Urinary Antispasmodics Anticholinergic drugs are the drugs of choice for their antispasmodic effects on smooth muscle to relieve the symptoms of urinary incontinence and frequency that accompany an overactive bladder. In infections, such as cystitis, urethritis, and prostatitis, the drugs decrease the frequency and pain of urination. The drugs are also given to increase bladder capacity in enuresis, paraplegia, and neurogenic bladder. Oxybutynin (Ditropan XL, Gelnique, Oxytrol), the prototype, is a urinary antispasmodic that is available in oral and transdermal forms. Pharmacokinetics The oral preparation of oxybutynin has an onset of action 30 to 60 minutes, a peak of 3 to 6 hours, and a duration of 6 to 10 hours. The transdermal preparation has an onset of action of 24 to 48 hours, a variable peak, and a duration of action of 96 hours. The medication is metabolized in the liver and is excreted in the urine. It crosses the placenta and may enter the breast milk. Action Oxybutynin acts directly to relax the smooth muscle and inhibits the effects of acetylcholine at muscarinic receptors. A less potent anticholinergic than atropine, oxybutynin is more potent as an antispasmodic and devoid of antinicotinic activity at the skeletal neuromuscular junctions or https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IcdpKuauTn1W0lrWmCsonBYnaQIwEDgwdbmVgOEy99af… 1/4 10/19/23, 3:39 AM Realizeit for Student autonomic ganglia. Use Oxybutynin is administered for the relief of bladder instability associated with voiding in patients with uninhibited neurogenic and reflex neurogenic bladder. The extended-release tablets decrease the symptoms of overactive bladder, incontinence, urgency, and frequency. Use in Older Adults In older adults, the dosage of oxybutynin should not exceed 2.5 mg PO two to three times per day. Use in Patients With Renal Impairment The use of oxybutynin in the presence of renal impairment requires caution because of its elimination in the urine. Use in Patients With Hepatic Impairment The use of oxybutynin in the presence of hepatic impairment requires caution because it is metabolized by the liver. Adverse Effects The adverse effects of oxybutynin are consistent with the previous anticholinergic agents discussed in this module. The most commonly reported CNS adverse effects include drowsiness, dizziness, and blurred vision. Other adverse effects are dry mouth, nausea, urinary hesitancy, and decreased sweating. Contraindications Contraindications to oxybutynin are hypersensitivity to the medication, pyloric or duodenal ulcer, obstructive intestinal lesions, intestinal atony, megacolon, colitis, obstructive uropathies, glaucoma, myasthenia gravis, cardiovascular instability, and urinary retention. Nursing Implications Preventing Interactions Use of oxybutynin in combination with phenothiazines results in increased anticholinergic effects. The phenothiazines inhibit the cytochrome 450 enzyme CYP3A4 in the liver. This enzyme is required in the metabolism of oxybutynin. The inhibition of the enzyme results in a greater amount of oxybutynin that has not undergone first-pass metabolism contributing to oxybutynin toxicity. This same effect occurs if haloperidol is administered with oxybutynin. Also, https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IcdpKuauTn1W0lrWmCsonBYnaQIwEDgwdbmVgOEy99af… 2/4 10/19/23, 3:39 AM Realizeit for Student use of oxybutynin together with haloperidol reduces the effect of the haloperidol and results in the development of tardive dyskinesia. Administration of oxybutynin with amantadine or nitrofurantoin leads to increased toxicity of oxybutynin. Administering the Medication It is important that the extended-release medication is not cut, crushed, or chewed. Assessing for Therapeutic Effects The nurse assesses for patient reports of decreased urinary incontinence, urgency, and frequency. Assessing for Adverse Effects The nurse assesses for CNS depression. He or she also assesses for urinary hesitancy and retention as well as for impotence. In addition, it is necessary to assess for allergic reactions to the medication such as urticarial reactions. Other Drugs in the Class Darifenacin (Enablex) is a competitive, antimuscarinic, anticholinergic agent with selective affinity for M3 receptors involved in the contraction of the urinary bladder. Darifenacin is indicated for the treatment of overactive bladder, reducing symptoms of urge incontinence, urgency, and frequency. After oral administration, darifenacin is 98% protein bound and extensively metabolized in the liver by enzymes CYP3A4 and CYP2D6. A small group of people (~7% Caucasian and 2% African American) are poor metabolizers of the drug and may require reduced dosages to avoid adverse effects. Dosage should also be reduced in people with moderate hepatic dysfunction and avoided in those with severe hepatic impairment. Flavoxate was developed specifically to counteract spasm in smooth muscle tissue of the urinary tract. It has anticholinergic, local anesthetic, and analgesic effects. Thus, the drug relieves dysuria, urgency, frequency, and pain with genitourinary infections, such as cystitis and prostatitis. Solifenacin (Vesicare) is a competitive, antimuscarinic, anticholinergic agent indicated for the treatment of overactive bladder with symptoms of urgency, urge incontinence, and frequency. Solifenacin is well absorbed after oral administration, 98% bound to plasma proteins, and extensively metabolized in the liver by CYP3A4 enzymes. Dosages should be reduced in people with moderate renal or hepatic impairment, and solifenacin is not recommended for those with severe hepatic impairment. Solifenacin may prolong QT intervals, especially at higher dosages, potentially resulting in dysrhythmias. https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IcdpKuauTn1W0lrWmCsonBYnaQIwEDgwdbmVgOEy99af… 3/4 10/19/23, 3:39 AM Realizeit for Student Tolterodine (Detrol, Detrol LA) is a competitive antimuscarinic, anticholinergic agent that inhibits bladder contraction, decreases detrusor muscle pressure, and delays the urge to void. It is used to treat urinary frequency, urgency, and urge incontinence. Tolterodine is more selective for muscarinic receptors in the urinary bladder than in other areas of the body, such as the salivary glands, and therefore, anticholinergic adverse effects are less marked. Reduced doses (1 mg) are recommended for patients with hepatic dysfunction. Tolterodine is also available in an extended-release form. Trospium chloride is an antimuscarinic, anticholinergic drug for treatment of urgency, urge incontinence, and urinary frequency associated with overactive bladder. Trospium reduces the tone of smooth muscle in the bladder, exerting an antispasmodic effect. Because of its quaternary structure, less than 10% of an orally administered dose is absorbed, and food further delays absorption. Therefore, it is recommended that the medication be taken at least 1 hour before meals or on an empty stomach. Absorbed trospium is eliminated by a combination of glomerular filtration and active tubular secretion. Trospium has the potential for interaction with other drugs that are eliminated by active tubular secretion (e.g., digoxin, procainamide, pancuronium, morphine, vancomycin, metformin, tenofovir), resulting in increased serum concentration of either trospium or the coadministered drug because of competition for the urinary tubular pump. Reduced dosages of trospium are recommended for patients with renal insufficiency and those older than 75 years of age who may be less able to tolerate the adverse effects of anticholinergic drugs. https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IcdpKuauTn1W0lrWmCsonBYnaQIwEDgwdbmVgOEy99af… 4/4