BPH, Renal Failure, and Dialysis - Josh Corwin



BPH, Renal Failure, and Dialysis

BPH

BPH is associated with obstructed or irritated prostate. It is the most common benign tumor in men. Usually age-related. The prevalence of histological BPH in autopsy arises from 20% in men aged 41-50, 50% from 51-60, and 90% over 80 years old. As age increases, the prevalence increases. There is also possible genetic pre-disposition.

Overall Treatment Approaches

Watchful waiting should be done in patients with mild symptoms. If scoring is 0-7 on the AVA survey, it indicates mild symptoms

Drug Therapy

Alpha-1 Blockers

Alpha-1 blockers relax smooth muscle of the bladder neck and prostate. Helps treat urinary retention and other symptoms of BPH. Reduces obstruction of urine outflow. They improve urine flow rate, decrease urinary retention, and reduces the need to urinate at night. Used in the treatment of HTN and BPH.

There are varying degrees of 1st pass effect, therefore varying bioavailability. They are absorbed PO, highly protein bound, no CYP450 DDIs, and are excreted in bile, urine, and feces.

ADRs include CNS effects (dizziness and headache due to vasodilation), CVS effects (edema, reflex tachycardia, and orthostatic hypotension), and erectile dysfunction.

Drugs all end in “zosin”. Prazosin (Minipres) is the 1st selective alpha-1 blocker and has a shorter half-life. Along with Prazosin, Doxazosin (Cardura) and Terazosin (Hytrin) are used for BPH/HTN because they bind to alpha receptors in the vessels and prostate.

Tamsulosin (Flomax) is used for BPH only because they are specific for alpha receptors in the prostate. This drug causes the most erectile dysfunction of all alpha-1 blockers because it binds to alpha-1 receptors in the seminal vesicles (ejaculatory dysfunction). Alfuzosin (Uroxatral) is the newest drug and used for BPH only because it is very specific for alpha-1 in the prostate. Causes less sexual dysfunction.

5-Alpha Reductase Inhibitors

5-alpha reductase inhibitors are pregnancy category X. Pregnant women should not even touch the drug. They are testosterone derivatives that blocks 5-alpha reductase. This decreases DHT synthesis in the prostate gland, skin, and other target tissues. This helps reduce the size of the prostate and are best used with alpha-1 blockers. Used for BPH and male pattern baldness. They are absorbed PO and are metabolized by the liver.

ADRs include sexual dysfunction such as decreased libido, ED, and testicular pain. They are CYP450 substrates.

Drugs in this group have a “steride” ending. Finasteride (Proscar, Propecia) can be used for BPH and male pattern baldness. The dose for male pattern baldness is lower. Dutasteride (Avodart) is a newer drug that blocks type I and type II 5-alpha reductase. Not yet FDA-approved for male pattern baldness. It has better efficacy because it blocks to both types of 5-alpha reductase.

Herbal Therapy

Saw palmetto inhibits the 5-alpha reductase enzyme. Also have anti-inflammatory effects. Contraindicated in pregnancy and women of child bearing age because of hormonal effects. ADRs include headache, HTN, GI effects, and back pain. DDIs include anticoagulants, Antiplatelet drugs (increased bleeding risk), and oral contraceptives.

Others include pygeum africanum, Echinacea purpurea, hypoxis rooperi, pollen extract, and trembling poplar.

RENAL DISORDERS

Acute Renal Failure

Acute renal failure (ARF) occurs when clinical conditions are associated with rapid (days to weeks), steadily decreasing renal function (azotemia) with or without oliguria.

Causes:

1) Hemorrhage

2) Cardiomyopathy

3) Septicemia

4) Liver failure

5) Surgery

6) Malignant HTN

7) Glomerulonephritis

8) Bacterial Infections

9) Metabolic disorders – hypercalcemia, hyperuricemia

Drug-Induced Causes

1) NSAIDs

2) Antibiotics – aminoglycosides, vancomycin, beta-lactams, sulfonamides, and fluoroquinolones

3) Amphotericin

4) Foscavir

5) Digoxin

6) Cyclosporine

7) Methotrexate

8) Cisplatin

9) Radiocontrast dye

Prevention

1) With surgery – proper maintenance of normal fluid balance, blood volume, and BP

2) With burns – isotonic NaCl infusion

3) With hemorrhage – blood transfusion

4) With nephrotoxic drugs – hydration and proper monitoring

Treatment

1) Vasopressors include dopamine, which is used low dose for IV infusions. This improves renal blood flow and urine output. It is the adrenergic agonist of choice for ARG.

2) Diuretics include Furosemide and Mannitol. Mannitol is not used for HTN because it is an osmotic diuretic

3) Electrolytes help replace or maintain anything that is low.

4) Dialysis improves fluid and electrolyte balance. Must allow for adequate nutrition. Should be used in ARF that is uncomplicated ................
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