Module 8: Unit B Thyroid, T, ED, BPH

Question 1

Indication for levothyroxine (T4) (Synthroid)

Answer 1

hypothyroidism (all forms)

Question 2

MOA levothyroxine

Answer 2

Synthetic T4 is converted to active T3

Question 3

D2D Levothyroxine

Answer 3

Absorption is reduced by food, antacids, multivitamins, chelating agents, H2B, PPI, Fe, Mg. Some medications like phenytoin, rifampin, sertraline, and carbamazepine can increase the metabolism of levothyroxine.

Levothyroxine ↑ effects of warfarin and ↑ cardiac sensitivity to catecholamines

Question 4

What can OD of levothyroxine cause?

Answer 4

Thyrotoxicosis: tachycardia, tremor, nervousness, angina, insomnia, hyperthermia, heat intolerance, and sweating.

Question 5

What can overuse of levothyroxine cause?

Answer 5

Chronic overuse can accelerate bone loss and ↑ risk of AFIB

Question 6

BBW levothyroxine

Answer 6

should not be used for the treatment of obesity or for weight loss.

Question 7

Pt teaching and monitoring with levothyroxine

Answer 7

Levothyroxine should be given in the morning, by itself, with water and at least 30 (preferably 60) minutes before meals.

Long half-life (7 days). Check TSH 6-8 weeks after initiating med or changing dose. (Consider checking T4 if TSH remains high).

Maintain patient on the same brand when possible; if a change is necessary, check TSH and/or T4 in 6-8 weeks

Question 8

T replacement examples

Answer 8

topical testosterone gels, solutions, and patches (Androgel, Adroderm, Axiron)
Nasal testosterone gel (Natesto)
Parenteral testosterone:
T. cypionate (Depo-testosterone)
T. enthanthate (Delatestyrl)

Question 9

Indications for testosterone therapy

Answer 9

Male hypogonadism (<300)
Replacement therapy
Delayed puberty
Cachexia (wasting syndrome)

Question 10

Safety with T

Answer 10

Causes virilization in women, girls, and young boys (coarse body hair, deepening voice, clitoral/penile enlargement, increased libido).
Premature epiphyseal closure.
Hepatotoxicity.
↑ LDL, ↓ HDL
Accelerates prostate CA (after it occurs; not causative but proliferative)
Edema from retention of Na and H20
↑ risk of thromboembolic events (↑ H&H = hypercoagulable state)
ABUSE POTENTIAL
Rash-patches
Topicals can be transferred to others by skin-to-skin contact

Question 11

BBWs testosterone

Answer 11

​Blood pressure increases (oral testosterone undecanoate; subQ testosterone enanthate)
​
Secondary exposure (transdermal gel, transdermal solution):
​
Pulmonary oil microembolism (intramuscular testosterone undecanoate):

Question 12

What schedule is testosterone?

Answer 12

Scheulde III

Question 13

Monitoring with testosterone

Answer 13

Measure testosterone 2-3 weeks after initiating treatment and then every 3-6 months. Include CBC, CBP, and lipid profile at least every six months

Question 14

Examples of PDE 5 inhibitors

Answer 14

-NAFIL
sildenafil (Viagra)
tadalafil (Cialis)
vardenafil (Levitra)
avanafil (Stendra)

Question 15

Uses for: sildenafil (Viagra)
tadalafil (Cialis)
vardenafil (Levitra)
avanafil (Stendra)

Answer 15

Erectile dysfunction

Question 16

MOA PDE-5 Inhibitors (Viagria, etc.)

Answer 16

Selective inhibition of PDE-5 leading to ↑ cGMP in the penis, causing local artery dilation, ↓ venous outflow, and subsequent engorgement of the corpus cavernosum.

Question 17

Safety and D2D with PDE-5 Inhibitors

Answer 17

Hypersensitivity
Concurrent use (regularly/intermittently) of organic nitrates in any form (e.g., nitroglycerin, isosorbide dinitrate);
concomitant use of riociguat (Adempas)(a guanylate cyclase stimulator)

Question 18

Side effects PDE-5 Inhibitors

Answer 18

Hypotension, priapism, nonarteritic ischemic optic neuropathy, sudden hearing loss, HA, visual changes, flushing, dyspepsia.
May exacerbate OSA

Question 19

D2D PDE5-I

Answer 19

CYP3A4 inhibitors can ↑ levels (grapefruit, erythromycin, ketoazonole)

alpha-adrenergic blockers with PDE-5 inhibitors can lower BP and cause postural hypotension

NO NITRATES

Question 20

Considerations/counseling with PDE-5-I

Answer 20

Consider de-prescribing or changing medications known to cause sexual/erectile dysfunction: SSRIs (fluoxetine and paroxetine), mood stabilizers, TCAs, MAOIs, spironolactone, HCTZ, beta-blockers, clonidine, digoxin, and finasteride. Also, advise avoiding alcohol.

Counsel patients with CVD to NOT use PDE-5s with hypotension (<90/50 mm Hg); uncontrolled hypertension (>170/110 mm Hg); recent arrhythmias, stroke or MI (< six months), history of CAD with unstable angina; aortic stenosis,

Question 21

5-𝝰-reductase inhibitors

Answer 21

-ASTERIDE
finasteride (Proscar)
dutasteride (Avodart)

Question 22

Indications for:
finasteride (Proscar)
dutasteride (Avodart)

Answer 22

BPH
(generally best when treating men with large prostates and mechanical obstruction)

Question 23

MOA
finasteride (Proscar)
dutasteride (Avodart)

Answer 23

Reduces the size of the prostate (over time) by inhibiting 5-𝝰-reductase, which ↓ conversion of testosterone to dihydrotestosterone (DHT). As DHT ↓, prostate tissue shrinks (over 6-12 months)

dutasteride MOA is similar but has more complete inhibition 5-𝝰-reductase and has a long half-life of 5 week

Question 24

Safety considerations for finasteride (Proscar) and dutasteride (Avodart)

Answer 24

Teratogenic, pregnant women should not handle medication.
Patients should not donate blood while taking medication (and up to 6 months after stopping)
Can ↓ libido and ejaculate volume.
Gynecomastia
NOT intended to prevent cancer

Question 25

Monitoring with finasteride (Proscar) and dutasteride (Avodart)

Answer 25

Causes PSA to ↓; Repeat the PSA at six months. If PSA does not decrease, investigate for prostate CA

Question 26

Examples of 𝛼1-adrenergic antagonists

Answer 26

-SIN
tamsulosin (Flomax)
silodosin (Rapaflo)
doxazosin (Cardura)
terazosin (Hytrin)
alfuzosin (Uroxatral)

Question 27

indication:
tamsulosin (Flomax)
silodosin (Rapaflo)
doxazosin (Cardura)
terazosin (Hytrin)
alfuzosin (Uroxatral)

Answer 27

BPH
(generally best for treating men with smaller prostates and dynamic obstruction

Question 28

MOA
tamsulosin (Flomax)
silodosin (Rapaflo)
doxazosin (Cardura)
terazosin (Hytrin)
alfuzosin (Uroxatral)

Answer 28

𝛼1-adrenergic receptor blockade causes smooth muscle relaxation in the bladder neck, prostate capsule, & prostatic urethra, which ↑ urinary flow. Does NOT reduce prostate size.

Question 29

Safety/D2D with:
tamsulosin (Flomax)
silodosin (Rapaflo)
doxazosin (Cardura)
terazosin (Hytrin)
alfuzosin (Uroxatral)

Answer 29

nonselective agents (doxazosin, terazosin, alfuzosin) can ↓BP and cause dizziness, fainting, somnolence, and nasal congestion.

Use cautiously with antihypertensive medications, nitrates, PDE-5

tamsulosin and silodosin can cause abnormal ejaculation (failure, retrograde, reduced volume)
Does NOT lower PSA
CYP3A4 inhibitors can ↑levels of silodosin and alfuzosin