Direct Vasodilators

Question 1

MOA for hydralazine?

Answer 1

• Direct vasodilation of arterioles (little effect on vns)
• Exact mech unk, possibly d/t prostaglandins

Question 2

Effects of hydralazine?

Answer 2

↓ systemic resistance

Question 3

CAs of hydralazine?

Answer 3

• HFrEF (intol to ACEI or ARB)
• HFrEF NYHA class III-IV (African American pts)
• Hypertensive emergency in pregnancy
• Postop HTN

Question 4

PKs of hydralazine?

Answer 4

• Oral or IV
• Hepatically acetylated w/ extensive first pass
• Urine excretion
• half-life 2-8 hrs, ↑ with ↓GFR

Question 5

Toxities of hydralazine?

Answer 5

• CV: angina pectoris, flushing, orhto hypotension, palps, paradoxical HTN, periph edema, tachy, vasc collapse
• CNS: Anxiety, chills, depression, disorientation, dizzy, fever, HA, ↑ ICP, psychotic rxn
• Derm: pruritis, rash, urticaria
• GU: dysuria, impotence
• GI: anorexia, constipation, NVD, paralytic ileus
• Heme: angranulocytosis, eosinophilia, erythrocyte count ↓, ↓ Hb, hemolytic anemia, leukopenia
• Neuromusc & Sk: muscle cramps, periph neuritis, RA, tremor, weakness
• Ocular: conjunctivits, lacrimation
• Resp: dyspnea, nasal congestion
• Misc - diaphoresis, drug-induced lupus-like syndrome

Question 6

MOA or nitroprusside?

Answer 6

• Causes peripheral vasodilation by direct axn on venous & arteriolar sm m

Question 7

Effx of nitroprusside?

Answer 7

• ↓ peripheral resistance
• ↑ CO by ↓ afterload

Question 8

CAs of Nitroprusside?

Answer 8

• HTN crisis
• ADHF
• Controlled hypotension to ↓ bleeding during surgery
• Off-label: HTN during ischemic stroke

Question 9

Pks of nitroprusside?

Answer 9

• IV
• half life = ~ 2min
• Eliminated in urine as thiocycanate

Question 10

Toxicities of nitroprusside?

Answer 10

• CV: flushing, hypotension, palps, substernal distress, tachy
• CNS: apprehension, dizzy, HA, ↑ ICP, restlessness
• Derm: rash
• Endocrine & metabolic: metabolic acidosis d/t cyanide; hypothyroidism
• GI: abd pain, ileus, NV, retching
• Heme: methemoglobinemia, PLT aggregation ↓
• NM & Sk, ocular: muscle twitching & miosis d/t thiocyantate
• Otic: tinnitus d/t thiocyanate toxicity
• Resp: hyperoxemia d/t cyanide toxicity

Question 11

MOA of Minoxidil?

Answer 11

• Vasodilation by directly relaxing arteriolar sm m, w/ little effect on vns; may be mediated by cAMP
• Stimulation of hair growth is secondary to vasodilation, ↑ cutaneous BF and stimulation of resting hair follicles

Question 12

Effects of minoxidil?

Answer 12

Lowers arteriolar vascular resistance

Question 13

CAs of minoxidil?

Answer 13

• HTN that is symptomatic or assoc w/ target organ damage, and is not managed w/ max doses of diuretic plus 2 other anti-htn
• Not recommended for milder HTN

Question 14

Pks of minoxidil?

Answer 14

• ~90% metab by glucuronidation
• half life ~4 hrs
• Excreted in urine

Question 15

Minoxidil toxicities?

Answer 15

• CV: ECG changes (T wave), edema, pericardial effusion (occassionally with tamponade), angina, CF, pericarditis, tachy
• Derm: hypertrichosis
• Endo & Metab: Na+ retention, water retention, wt gain
• GI: NV
• Heme & Onc: transient ↓ in hematocrit d/t hemodilution
• Hepatic: ascites, ↑serum alk phos
• Resp: pulm edema