Antiplatelet Drugs


- Works on Cyclo-oxygenase (AA -> thromboxane)

- Low dose (80-160 mg/day) irreversibly inhibits plt COX, and they can’t make new COX b/c they have no nucleus

- Some inhibition of endothelial COX but not much, therefore prostacyclin (anti-coag) synthesis isn’t  affected much
- Benefit is greater after thrombolysis

- SE is bleeding

- Prophylaxis for MI or TIA (80mg/day), higher doses for post-MI/TIA (160-325mg/day)

- Contraindications (bleeding risk):  Vit. K def., Hemophilia, Hypoprothombinemia, pregnancy & childbirth


- ADP antagonist

- Competes with ADP for P2Y receptor (prevents lowering of cAMP)

- Less incidence of neutropenia/thrombocytopenia

- Used in combo with ASA


- ADP antagonist, prodrug

- Often used in combo with ASA (synergistic)

- May cause severe neutropenia (1%)



- phosphodiesterase inhibitor (prevents cAMP breakdown)


GpIIb-IIIa inhibitors

-  Eptifibatide, Abciximab, Tirofiban

-  Block the receptor for fibrinogen blocking plt Aggregation


Heparin (& derivatives)

- Stimulates natural anticoags (antithrombin)


- Monitor using aPTT (add negative charges)

- Negatively charged, therefore cannot cross membranes (given IM, IV, parentally)

- Good for pregnancy

- Eliminated by RES & macrophages

- Potentiates AT III (in the plasma) – inhibits IIa, Xa, IXa and VIIa

- Toxicity – hemorrhage

- Antidote – protamine sulfate (1mg for every 100 units of heparin)

Heparin-Induced Thrombocytopenia (HIT) – occurs 5-10 days after, stop heparin immediately;  use alternatives lepirudin/danaparoid

- Good for PE and DVT and during pregnancy


LMWH – better bioavailability, can be given subcut. w/o lab monitoring as outpatient, less risk of bleeding

- More expensive, not good in renal failure, not for pregnancy

- DOES NOT inhibit IIa (but inhibit Xa)

- Good for DVT, PE and UA

Danaparoid – promotes inhibition of Xa by AT (for HIT)

Lepirudin – direct thrombin inhibitor (for HIT)


Coumarin (Oral) anticoags


- Monitored using PT (add tissue factor)

- Inhibit Vit. K Epoxide reductase in liver

-Prevents carboxylation of Vit.K dependent factors

-Takes 4-5 days to get effective (carboxylated fx’s in plasma need to be cleared before inactive ones take over)

-Small volume of distribution, steep dose-response curve (small therapeutic window)


- For DVT and PE, prosthetic heart valves or Afib, MI

-Metabolized by CYP1A and CYP2C9

-Efficacy measured by INR, pt’s PT time divided by PT time in pooled plasma

- INR = (PTpt/PTref)^ISI (target is 2.0 – 3.0)

- Warfarin overdose

- Give Excess Vit.K, goes through a diff  enzyme that isn’t inhibited by warfarin  (Diaphorase)

Fibrinolytics (lyse formed thrombi)

Streptokinase – turns plasminogen -> plasmin

-Plasmin breaks down fibrin (lysis of formed clot) Dissolves clots post-MI/DVT/PE

- SE – bleeding (systemic plasminogen activation), allergy, hTN, fever

- Streptokinase has an additive effect with ASA

Tissue plasminogen activator (tPA) – acts on fibrin and circulating plasminogen -> plasmin

- Less systemic plasmin

- Same indications as streptokinase

- More expensive

Alport’s Sd (most cases): "hereditary nephritis", type IV collagen deficit, mutation of COL4A5 ("colaas" - alpha-5 chain, type 4 collagen), hearing loss, ocular abnormalities (lens & cornea), hematuria since childhood (gross, micro)

Charcot Marie Tooth: loss of motor & sensory innervation, distal weakness & sensory loss, wasting in the legs, decreased deep tendon reflexes, tremor, foot deformity with a high arch is common (pes cavus), legs look like inverted champagne bottles. Most accurate test: electromyography. No tx.

Focal Dermal Hypoplasia: skin abnormalities and a wide variety of defects in eyes; teeth; and skeletal, urinary, gastrointestinal, cardiovascular, and central nervous systems.

Fragile X Syndrome: CGG trinucleotid repeat, FMR 1 gene mutation, mental retardation, large ears and jaw, post-pubertal macro-orchidism (males), attention deficit disorder (females)

Hypophosphatemic rickets: infants may show growth retardation, widened joint spaces and flaring at the knees at age 1 (> boys), bowing of the weight-bearing long bones, young children-dentition absent or delayed, older children-multiple dental abscesses.

Incontinentia pigmenti: skin abnormalities (blister--> warts--> hyperpigmentation--> hypopigmentation), alopecia, hypodontia, cerebral atrophy, slow motor development, mental retardation, seizures, skeletal & structural anomalies. Letal >males.

Orofaciodigital Sd: OFD1 gene mutation, malformations of face, oral cavity, digits with polycystic kidney disease and variable involvement of the central nervous system.

RETT’s Sd: sporadic mutation of MECP2 gene, onset 2yo, acquired microcephaly, stopped development, motor & speech regression, autism-like behavior, self-mutilating behavior, inconsolable crying/screaming fits, emotional inversion, hypotonia, dystonia, chorea, bruxism, scholiosis, long QT

Alport’s Sd: "hereditary nephritis", type IV collagen deficiency, alternating thickening & thinning of GBM, COL4A5 mutation, hearing loss, ocular abnormalities (lens & cornea), hematuria (gross or micro) since childhood.

Bruton’s Agammaglobulinemia: btk gene defect, no mature B cells or plasma cells, low lymphoid tissue, hepatitis, enterovirus infxs, first 6 months protected by maternal ab (no symptoms)

Becker’s Muscular Dystrophy: altered dystrophin gene, later onset than Duchene's, slow progression, relatively normal life span, less severe, rare cardiac involvement.

Chronic Granulomatose Disease (CGD): NAPDH oxidase deficiency, recurrent catalase (+) infxs, nitroblue tetrazolium test negative (yellow)

Congenital Aqueductus Stenosis: MCC of congenital obstructive hydrocephalus.

Color blindness (red-green): can't distinguish shades of red and green (usually blue-green)

Duchene’s muscular Dystrophy: dystrophin gene mutation (Xp21), absent dystrophyn protein, MC & severe of muscular dystrophies, normal until 5yo, short life span (<30yo), progressive muscle weakness, calf pseudohypertrophy, <3 failure, arrythmias, respiratory insufficiency and infxs (decreased mucociliary clearence). Pneumonias CC of death.

Fabry’s Disease: alpha Galactosidase A, Ceramide trihexose accumulation, angiokeratomas, renal failure, peripheral neuropathy.

Glucose 6-P Dehydrogenase (G6PD) Deficiency: chronic hemolytic anemia, MCC of enzymatic deficiency HA, Heinz bodies, bite cells. Triggers are infections, drugs (antimalarial), fava beans

Hemophilia A & B: factor VIII & IX deficiency respectively. PTT prolongation.

Hunter Disease: iduronate sulfatase deficiency, heparan sulfate accumulation, no corneal clouding, aggressive behaviour.

Inherited Nephrogenic Diabetes Insipidus: V2 receptors in collecting duct don't respond to ADH.

Lesch-Nyhan Sd: HGPRT1 deficiency, spastic cerebral palsy, self-mutilation, hyperuricemia, oral crystals in diapers, early death.

Menkes Disease: ATP7A gene mutation (copper efflux protein), Cu+ is lysil oxidase cofactor, Cu+ accumulates in intestine & kidneys; deficient in other tissues = deficient collagen cross linking; steely 'kinky' hair, MR, arterial tortuosity, hypotonia.

Ornithine Transcarbamoylase Deficiency: urea cycle, orotic aciduria + hyperammonemia (no megaloblastic anemia), orotic acid accumulation, increased glutamine . Cerebral edema, lethargy, vomiting, hyperventilation, convulsions, coma, death.

SCID: IL-receptor, Gamma chain deficiency

Wiskott Aldrich Sd: combined partial B & T immunodeficiency, IgM deficiency, thrombocytopenia, eczema.

 Abetalipoproteinemia: decrease ApoB-48, Apo B-100; pigmentary degeneration of retina, acanthocytes, steatorrhea, cerebellar ataxia.
 Acute Fatty Liver of Pregnancy: microvesicular steatosis in the liver, mitochondrial dysfunction in the oxidation of fatty acids leading to an accumulation in hepatocytes
  Alkaptonuria: homogentisate oxidase deficiency, increase homogenistic acid, ochronosis, dark blue urine.
  AcylCoA Dehydrogenase deficiency (MCAD): fasting hypoglycemia, no ketone bodies, dicarboxilic acidemia.
  Bernard Soulier Sd: gp1b deficiency, prolonged bleeding time
  Bloom Sd: chromosome 15, Ashkenazi Jews, BLM gene.
  Carpenter Sd: craniosynostosis, acrocephaly, craniofacial asymmetry, increased ICP, cutaneous syndactyly, polydactily, mild-profound MR.
  Chediak Higashi Sd: Lyst gene mutation, microtubule polymerization defect, no phagolysosome formation, albinism.
  Chondrodystrophy: normal-sized trunk and abnormally short limbs and extremities (dwarfism)
  Congenital Adrenal Hyperplasia: 17alpha or 21beta or 11 beta hydroxylase deficiency; enlargemente od adrenal glands due to increase ACTH
  Congenital Hepatic Fibrosis: hepatic (periporta) fibrosis, irregularly shaped proliferating bile duct, portal hypertension, renal cystic disease.
  Cystic Fibrosis: CFTR gene, Phe508, defective Chloride channel, chromosome 7.
  Dubin-Johnson Sd: direct hyperBbnemia, cMOAT deficiency, black liver
  Endocardial Fibroelastosis: restrictive/infiltrative cardiomyopathy, thick fibroelastic tissue in endocardium of young children, <2yo
Familial Mediterranean Fever: chromosome 16, recurrent autoinflammatory disease, characterized by F°, PMN disfx, sudden attacks pain/inflammation (7 types of attacks (abdominal, joints, chest, scrotal, myalgias, erysipeloid, fever). Complication: AA-amyloidosis
  Fanconi Anemia: genetic loss of DNA crosslink repair, often progresses to AML, short stature, ↑incidence of tumors/leukemia, aplastic anemia
  Friedreich’s Ataxia: GAA triplet repeat, chromosome 9, neuronal degeneration, progressive gait & limb ataxia, arreflexia, hypertrophic cardiomyopathy, axonal sensory neuropathy, kyphoscoliosis, dysarthria, hand clumsiness, loss of sense of position, impaired vibratory sensation.
 Gaucher’s disease: glucocerebrosidase deficiency, glucocerebroside accumulation, femur necrosis, crumpled paper inclusions in macrophages.
Ganzman’s thromboasthenia: gpIIbIIIa deficiency, deficient platelet aggregation.
Hartnup Disease: tryptophan deficiency, leads to niacin deficiency, pellagra-like dermatosis
Hemochromatosis: HFE gene, C282Y MC mutation, chromosome 6, unrestricted reabsorption of Fe+ in SI, iron deposits in organs, bronze diabetes, DM1, malabsorption, cardiomyopathy, joint degeneration, increased iron, ferritin, TIBC. Complications: liver cirrhosis, hepatocelullar carcinoma
Homocystinuria: due to B6 deficiency (defective Cystathionine synthase) or due to B9,B12 deficiency (defective Homocysteine Methyltrasnferase), dislocated lenses (in & down), DVT, stroke, atherosclerosis, MR.
Krabbe's Disease: Galactocerebrosidase deficiency, galactocerebroside accumulation, gobloid cells, optic atrophy, peripheral neuropathy.
Leukocyte Adhesion Defect (LAD): CD-18+ deficiency, omphalitis in newborns, chronic recurrent bacterial infxs, increase WBC count, no abscess or pus formation.
  Metachromic Leukodystrophy: Aryl-sulfatase A deficiency, sulfatides accumulation, Demyelination (central & peripheral), Ataxia, Demantia (DAD)
  Niemann-Pick Disease: sphingomyelinase deficiency, sphingomyelin accumulation, HSM, cherry-red macula, foam cells.
Phenylketonuria (PKU): phenylalanine hydroxylase deficiency, Phe accumulation, MR, microcephaly, diet low in Phe!!! also in pregnancy, avoid aspartame, musty odor.
Polycystic Kidney Disease (children): ARPKD, rogressive & fatal renal failure, multiple enlarged cysts perpendicualr to renal capsule, association with liver cysts. Bilateral palpable mass.
  Rotor Sd: direct hyperBbnemia, cMOAT deficiency, no black liver
Shwaman Diamond Sd: exocrine pancreatic insufficiency (2°MCC in children after CF), bone marrow dysfunction, skeletal abnormalities, short stature.
Situs inversus: assoc w/ Kartagener sd
Sicke Cell Disease and Trait: Hb S, beta globin chain, chromosome 11, position 6, nucleotide codon change (glutamic acid --> valine), vaso-occlusive crisis (pain), autosplenectomy, acute chest pain sd, priapism, hand-foot sd, leg ulcers, aplastic crisis, drepanocytes & Howell-Jolly bodies, hemolytic anemia, jaundice, bone marrow hyperplasia
 Tay-Sachs Disease: Hexoaminidase A deficiency, GM2 accumulation, cherry-red macula, onion skin lysosomes.
Thalasemia: alpha (chromosome 16, gene deletion), beta (chromosome 11, point mutation)
Werner Disease: adult progeria
  Wilson’s Disease: Chromosome 13, WD gene, ATP7B gene (encondes for Copper transporting ATPase), copper accumulation in liver, brain (putamen), eyes (Descemet membrane - Kayser-Fleischer ring), decreased ceruloplasmin.
  Xeroderma Pigmentosa: defective excision endonuclease, no repair of thymine dymers caused by UV radiation, excessive freckling, multiple skin cancers.