ED Pharmacology Flashcards
What is BPH
prostate enlargement can cause symptomatic obstruction of the male urethra, causing the sensation of not fully emptying the bladder, increased frequency in urination, unintended interruptions in stream while urinating, and urinary straining.
May be caused by too much DHT or too many androgen. receptors
How do alpha 1 antagonists work
Alpha-1 Antagonists act to improve urine flow by means of partial reversal of smooth muscle contraction within the enlarged prostate
What are the main alpha 1 inhibitors
doxazosin, terazosin and tamsulosin
Impact of Alpha 1 antagonists on blood pressure
Can cause hypotension and reflexive tachycardia, can be good if patient has BPH and hypertension
Which alpha 1 antagonist has the least impact on bp
Tamsulosin is different from other alpha-1 antagonists because it targets one particular subtype of receptor
Other side effects of a1 antagonists besides impacts on bp
Can negatively effect ejaculation
Floppy iris syndrome
Most common 5 a reductase inhibitors for BPH
FInasteride and dutasteride
Common side effects of 5 a reductase inhibitors
sexual dysfunction and depression
Which is frist-line treatment for BPH
Alpha-1-adrenergic antagonists provide immediate therapeutic benefits and are usually considered first line treatment for BPH. 5-alpha-reductase inhibitors require long-term treatment for efficacy, taking 6-12 months before causing a “symptom-relieving” decrease in prostate size.
What two things are needed for erection
parasympathetic innervation and nitric oxide
How does NO cause erection
Nitric oxide activates guanylyl cyclase, thus increasing the concentration of cGMP, leading to second messenger activation, dephosphorylation of myosin light chains and finally relaxation of smooth muscle
How do most medications for ED work
Work to increase cGMP
How do Phosphodiesterase 5-Inhibitors work
act to increase cGMP by inhibition of its metabolism by phosphodiesterase isoform 5 (PDE-5), allowing prolonged effect of smooth muscle relaxation. Remember, increased cGMP is initiated by nitric oxide release from cholinergic motor input. Thus, in order for this drug to work, there has to be an intact nervous system with stimulating signals.
Most common Phosphodiesterase-5 inhibitors
tadalafil, sidenafil, and vardenafil
Side effects of PDE-5 inhibitors
PDE-5 inhibitors as a whole have vasodilatory effects and can potentiate the actions of nitrates (potent vasodilators used to treat chest pain, more on this in future lectures). Severe hypotension can occur, which may lead to myocardial infarction as the heart is unable to be adequately perfused. It is recommended that at least 6 hours pass between usage of these drugs together.
Lastly, Sildenafil is known to potentially effect color vision, particularly in blue-green discrimination. This effect is easily remembered if you recognize that sildenafil’s brand name is Viagra (“the little blue pill”).
What are the causes for ED (acronym and words)
