Low Molecular Weight Heparin
CLASS
- anticoagulant
MECHANISM OF ACTION
- potentiates the action of antithrombin III on Xa
PHARMACEUTICS
- injection: clear, colourless
- MW 2,000-6,000
DOSE
DVT prophylaxis:
- 40mg SC OD
- always chart dose at night -> procedures done during day will not be effected
Therapeutic anti-coagulation:
- 1mg/g BD or 1.5mg/kg OD-> dose adjust in renal failure
- calculate GFR
- loading dose: 1mg/kg (for everyone)
- maintenance dosing based on GFR:
-> > 60mL/min – 1mg/kg Q12 hourly or 1.5mg/kg Q24 hourly
-> 30-60mL/min – 0.8mg/kg Q12 hourly
-> < 30mL/min – 0.66mg/kg Q12 hourly - can measure anti-Xa levels in therapeutic anti-coagulation (renal impairment + very low or very high BMI, pregnancy)
ANTI-Xa MONITORING
- establish steady state (48 hours of dosing)
- use peak 4 hours after dose
- mostly not recommended
- therapeutic range = peak 0.5-1.2 IU/mL (BD dosing), 1-2 IU/mL (OD dosing)
- troughs not routinely recommended:
-> in BD dosing trough > 0.5 IU/mL at 12 hours post dose then patient can be changed to once daily dosing)
-> in OD dosing trough should be < 0.4 IU/mL at 20 hours post dose
DOSE ADJUSTMENT
- depending on peak level -> adjust by 25-50%
- repeat level after 48 hours
INDICATIONS
(1) DVT prophylaxis
(2) therapeutic anticoagulation
- VTE
- ACS
- arterial thrombosis
- AF
- bridging therapy for the chronically anti-coagulated
CONTRAINDICATIONS
- hypersensitivity
- bleeding
- procedures/surgery
- uncontrolled hypertension
- recent high risk surgery (CNS, TURP, eye)
ADVERSE EFFECTS
- bleeding
- decreased incidence of HITS
PHARMACOKINETICS
- Absorption – higher bioavailability than heparin
- Distribution
- Metabolism
- Elimination – t ½ = 2-3 hrs
References and Links
CCC Pharmacology Series
Respiratory: Bosentan, Delivery of B2 Agonists in Intubated Patients, Nitric Oxide, Oxygen, Prostacyclin, Sildenafil
Cardiovascular: Adenosine, Adrenaline (Epinephrine), Amiodarone, Classification of Vasoactive drugs, Clevidipine, Digoxin, Dobutamine, Dopamine, Levosimendan, Levosimendan vs Dobutamine, Milrinone, Noradrenaline, Phenylephrine, Sodium Nitroprusside (SNiP), Sotalol, Vasopressin
Neurological: Dexmedetomidine, Ketamine, Levetiracetam, Lignocaine, Lithium, Midazolam, Physostigmine, Propofol, Sodium Valproate, Sugammadex, Thiopentone
Endocrine: Desmopressin, Glucagon Therapy, Medications and Thyroid Function
Gastrointestinal: Octreotide, Omeprazole, Ranitidine, Sucralfate, Terlipressin
Genitourinary: Furosemide, Mannitol, Spironolactone
Haematological: Activated Protein C, Alteplase, Aprotinin, Aspirin, Clopidogrel, Dipyridamole, DOACs, Factor VIIa, Heparin, LMW Heparin, Protamine, Prothrombinex, Tenecteplase, Tirofiban, Tranexamic Acid (TXA), Warfarin
Antimicrobial: Antimicrobial Dosing and Kill Characteristics, Benzylpenicillin, Ceftriaxone, Ciprofloxacin, Co-trimoxazole / Bactrim, Fluconazole, Gentamicin, Imipenem, Linezolid, Meropenem, Piperacillin-Tazobactam, Rifampicin, Vancomycin
Analgesic: Alfentanil, Celecoxib, COX II Inhibitors, Ketamine, Lignocaine, Morphine, NSAIDs, Opioids, Paracetamol (Acetaminophen), Paracetamol in Critical Illness, Tramadol
Miscellaneous: Activated Charcoal, Adverse Drug Reactions, Alkali Therapies, Drug Absorption in Critical Illness, Drug Infusion Doses, Epidural Complications, Epidural vs Opioids in Rib Fractures, Magnesium, Methylene Blue, Pharmacology and Critical Illness, PK and Obesity, PK and ECMO, Sodium Bicarbonate Use, Statins in Critical Illness, Therapeutic Drug Monitoring, Weights in Pharmacology
Toxicology: Digibind, Flumazenil, Glucagon Therapy, Intralipid, N-Acetylcysteine, Naloxone, Propofol Infusion Syndrome
- Emergency Medicine PharmD — Protamine for LMWH (2013)
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC