Prostaglandins / Leukotrienes

Question 1

Alprostadil

Answer 1

• PGE1 Analog
• Maintain patency of Ductus Arteriosus [congenital heart disease]
• Vasodilation corpus cavernosum [erectile dysfunction pts on nitrates]
• IV infusion (labile) or SC, topical
• Aka: Prostin VR, Topiglan

Question 2

Epoprostenol

Answer 2

• PGI₂ Analog, $$$$
• Vasodilator and inhibitor of platelet aggregation [1° pulmonary hypertension]
• G_s activation
• Cont. IV infusion, plasma t1/2 ~ 6 min
• Aka: Flolan

Question 3

Treprostinil

Answer 3

• Prototype to replace Epoprostenol
• Longer t1/2 - Infused SC or IV
• Aka: Remodulin

Question 4

Latanaprost

Answer 4

• PGF_2a Analog
• Inc. uveoscleral outflow [open angle glaucoma]
• Topical (eye drops)
• Can alter iris/lash pigmentation (permanent)
• Aka: Xalantan

Question 5

Misoprosol

Answer 5

• PGE₁ Analog
• Inhibit cAMP (decrease membrane insertion of H⁺/K⁺ ATPase) inc. mucin and bicarb [peptic ulcer]
• Expel blastocyst post methotrexate/RU-486 [uterine contraction]
• PO
• Aka: Arthrotec, Ctytotec

Question 6

Dinoprostone

Answer 6

• PGE₂ Analog
• Induces contraction of preg uterus [abortion, postpartum hemorrhage] & cervical ripening
• Vaginal suppository
• Aka: Cervidil, Prostin E2

Question 7

Carboprost

Answer 7

• 15-methyl PGF_2a Analog
• Induces contraction of preg uterus [abortion/postpartum hemorrhage]
• IM
• Inc. incidence arrythmias (used less)
• Aka: Hemabate

Question 8

Zafirlukast

Answer 8

• LT Inhibitor / Comp antagonist of CysLTR₁
• Antagonizes smooth muscle contraction [asthma]
• PO BID, rapid absorb, peak conc. 3-4 hrs, t1/2 10hrs (3 d to start working), hepatic p450 metabolism
• AEs: GI complaints, headache, inc aminotransferase levels. Rare Churg-Strauss Syndrome (allergic granulomatosis, vasculitis)
• Drug Interaction: Warfarin/fentanyl
• Aka: Accolate

Question 9

Montelukast

Answer 9

• LT Inhibitor / Comp antagonist of CysLTR₁
• Antagonizes smooth muscle contraction [asthma]
• PO, rapid absorb, peak conc. 3-4 hr, t1/2 2.7-5.5 hrs (d to start working, wk max effect), hepatic p450 metabolism, excreted in bile
• AEs: few ? Rare Churg-Strauss Sydrome (allergic granulomatosis)
• OK in children > 12 mo
• Aka: Singulair

Question 10

Zileuton

Answer 10

• LT Inhibitor / 5-Lipox inhibitor
• Antagonizes smooth musc. contraction [asthma], maybe helpful in [RA, IBDs]
• PO QID, eff in few hrs, rapid absorb, peak conc. 1-3 hrs, p450 metabolism, renal excretion
• AEs: hepatitis
• Drug interaction: Warfarin/fentanyl, theophylline
• Aka: Zyflo