Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Neuropharmacology wikipedia , lookup
Drug discovery wikipedia , lookup
Intravenous therapy wikipedia , lookup
Pharmacokinetics wikipedia , lookup
Drug design wikipedia , lookup
Drug interaction wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Discovery and development of direct Xa inhibitors wikipedia , lookup
Dydrogesterone wikipedia , lookup
Discovery and development of direct thrombin inhibitors wikipedia , lookup
DVT and PE Pharamcotherapy TEACHING SLIDES Olavo Fernandes Pharm.D. Pharmacy Practice Leader, University Health Network Assistant Professor, University of Toronto October 2002 UHN Residency Open House • Monday October 21st, 2002 5:30 pm to 8:00 pm • Princess Margaret Hospital 610 University Ave 5th Floor Cafeteria • The evening will include: • An information session on our residency program A question and answer period Tours of the department and the hospitals • Food will be provided • Please RSVP to Tamar / Nancy at 416-340-3611 • By October 18th, 2002 DEFINTIONS DVT • thrombus material composed of cellular material (RBC, WBC, Plts) bound together with fibrin strands • forms in the venous portion of the vasculature PE • thrombus from from systemic circulation lodges in pulmonary artery or branches causing complete or partial obstruction of pulmonary blood flow • 95% originate from DVT • Submassive – <50 % of pulmonary vascular bed occluded • VTE= DVT + PE • Massive – <50 % of pulmonary vascular bed occluded EPIDEMIOLOGY DVT • 48 per 100, 000 PE • 69 per 100, 000 (with our without associated DVT) • 100, 000 deaths annually due to PE • Mortality (30% untreated; 8% with treatment ) PATHOPHYSIOLOGY • Virchow’s Triangle – abnormalities in blood blow • (bed rest, tumour obstruction) – abnormalities in clotting function • (malignancy, pregnancy, deficiencies in Anti-thrombin III, Ptn S or C) – abnormal vascular surfaces • (catheters, vascular injury, trauma) • To form a clot: imbalance in triangle; activation of intrinsic and extrinsic pathway and cascade • Venous Thrombi (red) • Arterial Thrombi (white) RISK FACTORS for DVT • • • • • • • surgery or trauma MI stroke increasing age prior VTE estrogen use Factor V leiden • • • • • • • • Anti-phospholipid syndrome pregnancy CHF Cancer obesity prolonged immobilization Smoking Ptn C or S or antithrombin deficiency • HIT CLINICAL PRESENTATION DVT • • • • • • • • • symptoms present when – obstruction of venous flow – inflammation of vein wall or perivascular space – embolization to lung unilateral leg pain leg tenderness leg swelling redness/ discolouration palpable cord venous distention Homan sign (calf pain on dorsiflexion of the foot) SILENT presentation PE • • • • • • • • • • • • *transient dyspnea (84%) tachypnea (RR > 20) 85% +pleuritic chest pain (74%) *apprehension (63%) tachycardia (HR > 100) (58%) cough (50%) +hemoptysis (28%) *syncope (13%) hypoxemia, hypotension, cardiogenic shock *more often assoc with massive PE +more often assoc with submassive PE SILENT presentation Endpoints: Outcome Assessment • VTE endpoints – Venography – Duplex compression ultrasonography – Impedance Plesmography – Fibrinogen Uptake – D-Dimer Testing – PE (lung scanning, angiography, autopsy) • Safety endpoints – Major and minor bleeds – Thrombocytopenia • Mortality MANAGEMENT OPTIONS DVT • pharmacological agents • surgery (rarely indicated) PE • pharmacological agents • thrombolytics • surgery (endarterectomy, can be life saving, specialized centres) • Greenfield Filters (px) THERAPEUTIC OPTIONS • • • • • • • • • Heparin LMWH Warfarin (oral) Danaparoid Hirudin/ Lepirudin Ancrod Thrombolytics (PE) Pentasacharide Injection (phase 3) Thrombin inhibitors (oral) (phase 3) Pharmacologic Agents • • • • • • MOA Place in Therapy Dosing Monitoring Adverse Effects/ Limitations Reversal Agents HEPARIN • MOA: binds to antithrombin III • Monitor: aPTT heparin inhibition of thrombin (IIa) and factors Xa and IXa – platelets, bleeding • target: 1.5 -2.5 x control • onset: immediate • advantage: can stop if bleeding (t 1/2 short) • reversal: protamine effective • Unpredictable dose response requires monitoring • complications: HIT, long term osteoporosis • does not inactivate clot bound thrombin LMWH – MOA: preferentially inhibit factor Xa – Monitor: limited requirement ; antiXa for renal failure and obesity • platelets, bleeding – target: variable – onset: immediate – prolonged effectmore difficult to immediately reverse effect – reversal: difficult : protamine – OD vs. BID – as effective, same incidence of bleeds/ mortality • wt based dosing UFH and LMWH • Continue therapy for at least 5 days (Grade 1A) • longer duration of UFH or LMWH if massive PE • Should overlap with warfarin for at least 4-5 days. – D/C after 2 consecutive days of therapeutic INR Favourable properties of a LMWH – increased plasma half life- once daily/ bid dosing – reduced non-specific binding to plasma proteins (predictable anticoagulant response, predictable bioavialability) – reduced binding to platelets : (less HIT, potential for less bleeding) – less need for monitoring/ SC outpatient option – less daily injections – reduced binding to osteoblasts (less bone loss) Favourable properties of a LMWH – less expensive – short acting- desirable in patients at high risk of bleeding - can quickly reverse anticoagulation WARFARIN – MOA: inhibits vit K dep coagn factors (II, VII, IX, X) – Monitor: INR , bleeding – target: 2-3 unless MVR – onset: delayed clotting factor half lives (factor II 72 hrs) – reversal: Vitamin K • Bleeding risk correlated to INR – inc with INR > 4 – major bleeds < 3% INR 2-3 • Drug Interactions Duration of Warfarin Therapy • Reversible or time limited RFs - first event (3-6 months) • Idiopathic VTE- first event (> 6 months) • 12 mos- lifetime • first event with: cancer until resolved; antithrombin deficiency; anticardiolipin Ab • recurrent event, idiopathic or with thrombophilia WARFARIN DRUG INTERACTIONS : Increased INR • TMP/ SMX – inhibits hepatic metabolism of S-warfarin – increases response to warfarin (even 3 day course) • Amiodarone – dramatic increase – rough estimation - 50% decrease in therapeutic warfarin maintenance dose • Metronidazole – dramatic increase • Acetaminophen – interaction appears more likely at doses > 2000 mg/ day for a week or more • Ciprofloxacin – case reports - monitor INR • Fluconazole – inc INR especially with doses > 200 mg/ day • Phenytoin – can both increase or decrease INR WARFARIN DRUG INTERACTIONS : Pharmacodynamic and dec. INR Pharmacodynamic • ASA • NSAIDS • clopidogrel, ticlopidine Decreased INR • carbamazepine • Binding resins • barbituates WARFARIN COUNSELLING POINTS • Indication • How it works• prevents abnormal clots; stop existing clots from getting larger, decreases risk of clot breaking off • Blood Test Monitoring (INR) • Administration • Length of Therapy • Risks: bleeding (practical discussion) – advise dentist • Drug interactions – Rx and Herbal – Diet • Alcohol • Missed pills WARFARIN COUNSELLING POINTS • When to contact MD: blood in urine, stool, persistent nose bleed, increased swelling in extremity • When to go to ER: – SOB, Chest pain, coughing up blood, black tarry stools, severe HA of sudden onset, slurred speech Thrombolytics for PE • Indicated only if massive PE, submassive with hemodynamic compromise (or failure of heparin tx) • can start 7-14 days after PE dx • only when dx certain (V/Q scan, angiography) • only if no contraindications – absolute (active bleed; CVA or neurosurg in last 10 days) – relative (sx in last 10 days; severe HTN, pregnancy, GI bleed in last 3 months), arotic aneurysm, diabetic retinopathy, serious recent trauma • bleeding risks • expensive Indications for Exoxaparin • Non-ST segment elevation ACS – angina at rest lasting at least 10 min – evidence of underlying IHD - specific ECG changes – inpatients • Exclude: – chest pain NYD, persistent ST segment elevation; emergency intervention within 24 hrs