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Flashcards in MSK Drugs Deck (36)
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1
Q

Two main pathways for arachidonic acid metabolism

A
  1. Lipoxygenase –> Leukotrienes

2. COX pathways (COX-1, COX-2) –> Prostaglandins, Thromboxane

2
Q

LBT4

A

Attracts neutrophils

3
Q

LTC4, LTD4, LTE4

A

Function in bronchoconstriction, vasoconstriction, contraction of smooth muscle and increase in vascular permeability

  • Target of anti-leukitriene medications in asthma
4
Q

PGI2

A

Inhibits platelet aggregation and promotes vasodilation

PGI = “Platelet Gathering Inhibitor”

5
Q

Prostaglandins (PGE2, PGF2)

A
  • Increase uterine tone
  • Decrease vascular tone
  • Decrease bronchial tone

** Aspirin causes wheezing because these prostaglandins are blocked due to COX inhibiton so only bronchoconstriction causing leukotrienes are left

6
Q

Thromboxane

A
  • Increase platelet aggregation
  • Increase vascular tone
  • Increase bronchial tone
7
Q

Aspirin: Mechanism

A

IRREVERSIBLY inhibits COX-1 and COX-2 by acetylation which decreases thromboxane and prostaglandins

  • Increase bleeding time
  • No effect on PTT, PT
8
Q

Aspirin: Clinical Use

A

Low dose (< 300 mg/day): decreased platelet aggregation

Intermediate dose (300 - 2400 mg/day): antipyretic and analgesic

High dose (2000 - 4000 mg/day): anti-inflammatory

9
Q

Aspirin: Toxicity

A

Gastric ulceration (due to COX-1 inhibition which maintains GI mucosa)

  • Tinnitus
  • Chronic use can lead to renal failure, interstitial nephritis and upper GI bleeding
  • Reye’s syndrome when used in children for tx of viral infection
  • Aspirin- induced asthma, Hyperventilation (respiratory alkalosis)
10
Q

NSAIDS

A

Ibuprofen, Naproxen, Indomethacin, Ketorolac, Diclofenac

11
Q

NSAIDs: Mechanism

A

REVERSIBLY inhibit cyclooxyenase (both COX-1 and COX-2). Block prostaglandin synthesis

12
Q

NSAIDs: Clinical Use

A

Antipyretic, analgesic, anti-inflammatory

13
Q

Tx for PDA closure

A

Indomethacin

14
Q

NSAIDs: Toxicity

A

Interstitial nephritis
Gastric ulcer
Renal ischemia (PG vasodilate afferent arteriole

15
Q

COX-2 inhibitors

A

Celecoxib

16
Q

COX-2 Inhibitors (Celecoxib) : Mechanism

A

Reversibly inhibit COX-2, which is found in inflammatory cells and vascular endothelium and mediates inflammation and pain

  • Spares GI lining (normally maintained by COX-1
  • Spares platelet function as platelet normally associated with COX-1
17
Q

Celecoxib (COX-2 inhibitor): Toxicity

A

Increased risk of thrombosis (can lead to acute MI). Sulfa allergy

18
Q

Acetaminophen

A

Reversibly inhibits COX, mostly in CNS. Inactivated peripherally

19
Q

Acetaminophen: Clinical use

A

Antipyretic, Analgesic, but not anti-inflammatory. Used instead of aspirin to avoid Reye’s syndrome in children with viral infection

20
Q

Acetaminophen: Toxicity

A

Overode produces hepatic necrosis as acetaminophen depletes glutathione (which protects against free radicals) and form toxic liver tissue.

21
Q

Tx for acetaminophen overdose

A

N-acetylcysteine - regenerates glutathione depleted with acetaminophen use

22
Q

Bisphosphonates

A

ends in -dronates

Alendronate

23
Q

Bisphosphonate: Mechanism

A
  • Pyrophosphate analog (critical component of hydroxyapatite in bone)
  • Bind hydroxyapatite in bone
  • Inhibits osteoclast activity
24
Q

Bisphosphonate: Clinical Use

A

Osteoporosis
Hypercalcemia
Paget’s disease of bone

25
Q

Bisphosphonate: Toxcity

A
Corrosive esophagitis (advise patients to sit up when taking)
- Osteonecrosis of jaw (contraindicated during dental work)
26
Q

Chronic gout drugs

A

Allopurinol, Febuxostat, Probenecid, Colchicine

27
Q

Allopurinol

A

Inhibits xanthine oxidase which decreases conversion of xanthine to uric aic

  • Used in lymphoma and leukemia to prevent tumor lysis - associated with urate nephropathy
  • Increase concentrations of azathioprine and 6-MP (both normally metabolized by xanthine oxidase)
28
Q

Discuss salicylates and drug use

A

Don’t give salicylates. All but high doses suppress uric acid clearance.

29
Q

Febuxosate

A

Inhibit xanthine oxidase

30
Q

Probenecid

A

Inhibits reabsorption of uric acid in PCT (also inhibits secretion penicillin)

31
Q

Colchicine

A

Binds and stabilizes tubulin to inhibit polymerixation, impairing leukocyte chemotaxis and degranulation

** GI side effects, especially if given orally

32
Q

Acute gout drugs

A

NSAIDs, Glucocorticoids (can be given orally or intraarticular)

33
Q

TNF-alpha inhibitors

A

Etanercept, Infliximab, Adalimumab

34
Q

Discuss TNF-alpha inhibitors and Infection

A

Can predispose to infection including reactivation of latent TB since TNF blockage prevents activation of macrophages and destruction of phagocytosed microbes

35
Q

Etanercept

A

Fusion protein (receptor for TNF-alpha + IG1Fc) produced by recombinant DNA

  • Is a decoy TNF receptor
  • used for Rheum Arthritis, Psoriasis, Ankylosing Spondylitis
36
Q

Infliximab, Adalimumab

A

Anti-TNF-alpha monoclonal antibody

  • Used for Crohn’s, Rheum Arthritis, Ankylosing Spondyltis, Psoriasis