Drug reference

Heparin

Anticoagulant

Also known as Unfractionated Heparin, Heparin Sodium, Liquaemin

START

80 U/kg IV bolus then 18 U/kg/h infusion (VTE), titrate to aPTT 1.5-2.5×

TYPICAL MAX

no fixed daily ceiling — titrate to aPTT or anti-Xa

STOP IF

Active bleed · HIT (Heparin-Induced Thrombocytopenia) · severe thrombocytopenia

WATCH

aPTT q6h until stable · platelets (HIT) · bleeding

CDSCO approvedJan AushadhiNPPA price-controlledATC B01AB01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 5min · IV immediate (5 min)
PEAK: 30min · IV peak effect
t½: 1.5h · plasma t½ (dose-dependent 0.5-2h)
DURATION: 4h · anticoagulant effect after IV bolus

EXCRETION

Reticuloendothelial uptake · hepatic depolymerization

route + CYP

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

Category C — does not cross placenta, safe in pregnancy

FDA category + note

Top interactionssee all 12 →

HydrocortisoneContraindicatedTextbookKDT 7e · p58
PenicillinContraindicatedTextbookKDT 7e · p58
StreptomycinContraindicatedTextbookKDT 7e · p58
TetracyclinesContraindicatedTextbookKDT 7e · p58

Available in India

72 branded formulations and 10 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Heparin binds to antithrombin III (AT-III), causing a conformational change that dramatically increases AT-III's ability to inactivate Factor Xa and thrombin (Factor IIa). This prevents the conversion of fibrinogen to fibrin, thereby inhibiting the formation and growth of new thrombi, and prolonging clotting times.

Indications

Prophylaxis and treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE)Prevention of clotting in arterial and cardiac surgeryPrevention of mural thrombi following myocardial infarctionAcute coronary syndromes (unstable angina, NSTEMI, STEMI) (off-label for some uses)Prevention of systemic embolism in atrial fibrillationAnticoagulation for extracorporeal circulation (e.g., hemodialysis, cardiopulmonary bypass)Maintenance of patency of intravenous catheters (heparin flush)Treatment of deep vein thrombosisTreatment of pulmonary embolismInitial management of unstable anginaInitial management of acute myocardial infarctionPrevention of thrombosis during coronary balloon angioplasty with or without stent placementCardiopulmonary bypassTreatment of selected patients with disseminated intravascular coagulationThromboprophylaxis in immobilized medically ill patientsThromboprophylaxis in patients who have undergone major surgeryprophylaxis of venous thromboembolismtreatment of venous thromboembolismacute coronary syndromepercutaneous coronary interventioncardiopulmonary bypass surgerydisseminated intravascular coagulationDeep vein thrombosis (treatment and prophylaxis)Pulmonary embolism (treatment and prophylaxis)Acute myocardial infarction (after recanalization, during angioplasty and stent placement)Unstable anginaRheumatic heart diseaseAtrial fibrillationCerebral embolismVascular surgery (prevention of thromboembolism)Prosthetic heart valves (prevention of thromboembolism)Retinal vessel thrombosis (prevention of thromboembolism)Extracorporeal circulationHaemodialysisDefibrination syndrome (disseminated intravascular coagulation)Interstitial Cystitis/Bladder Pain Syndrome (intravesical, often in 'cocktails')Initial treatment for deep venous thrombosis or pulmonary embolism in cancer patientsProphylaxis for cancer patients undergoing major surgical procedures

Dosing

Adult: For DVT/PE Treatment: Initial IV bolus of 80 units/kg, followed by continuous IV infusion of 18 units/kg/hour. Adjust infusion rate to maintain activated partial thromboplastin time (aPTT) at 1.5 to 2.5 times the control value. For DVT Prophylaxis: 5000 units subcutaneously every 8-12 hours.
Pediatric: For DVT/PE Treatment: Initial IV bolus of 75 units/kg, followed by continuous IV infusion of 20 units/kg/hour for infants and 25 units/kg/hour for children >1 year. Adjust infusion rate to maintain aPTT at 1.5 to 2.5 times the control value.
Renal adjustment: No specific dose adjustment for unfractionated heparin, as it is primarily cleared by the reticuloendothelial system. Monitor aPTT closely as elimination can be prolonged in severe renal impairment.
Hepatic adjustment: No specific dose adjustment for hepatic impairment, but use with caution and monitor closely due to increased bleeding risk.
Geriatric: Use with caution in elderly patients due to increased risk of bleeding. Consider lower initial doses or more frequent monitoring of aPTT.
Max dose: No absolute maximum dose; doses are adjusted based on aPTT and clinical response.

Pharmacokinetics

Onset

IV: Immediate; SC: 20-60 minutes

Peak effect

IV: Minutes; SC: 2-4 hours

Duration

IV: 2-6 hours (dose-dependent); SC: 8-12 hours

Half-life

Dose-dependent, typically 0.5 to 2.5 hours

Bioavailability

IV: 100%; SC: approximately 30% (highly variable)

Protein binding

High (up to 95%), non-specific to various plasma proteins and endothelial cells

Metabolism

Primarily depolymerization and desulfation by heparinase (lysosomal enzymes) in the reticuloendothelial system and endothelial cells.

Excretion

Primarily cleared by the reticuloendothelial system via depolymerization and desulfation. Metabolites and small amounts of unchanged heparin are excreted renally.

Contraindications

Active major bleeding
History of Heparin-Induced Thrombocytopenia (HIT)
Severe thrombocytopenia (platelet count <50,000/microL)
Uncontrolled severe hypertension
Recent intracranial, intraspinal, or eye surgery
Lumbar puncture or regional anesthetic procedures in patients who are to be anticoagulated
Bacterial endocarditis
Severe liver disease with impaired hemostasis
Hemorrhagic stroke
Bleeding disorders
History of heparin induced thrombocytopenia
Severe hypertension (risk of cerebral haemorrhage)
Threatened abortion
Piles
G.I. ulcers (risk of aggravated bleeding)
Subacute bacterial endocarditis (risk of embolism)
Large malignancies (risk of bleeding in the central necrosed area of the tumour)
Tuberculosis (risk of hemoptysis)
Ocular and neurosurgery
Lumbar puncture
Chronic alcoholics
Cirrhosis
Renal failure

Side effects

Common

Bleeding (e.g., bruising, hematoma, epistaxis, gum bleeding)Thrombocytopenia (non-immune, typically mild and transient)Elevation of liver enzymes (transaminases)Injection site reactionsHypersensitivity reactions (e.g., urticaria, rhinitis)Bleeding (major bleeding occurs in 1% to 5% of patients treated with intravenous heparin)Interfere with platelet aggregation (high doses)Prolong the bleeding time (high doses)Reversible abnormalities of hepatic function testsBleeding (most serious complication, haematuria generally first sign)Thrombocytopenia (mild and transient common)BleedingElevated levels of transaminases

Serious

Severe hemorrhage (e.g., gastrointestinal, retroperitoneal, intracranial)
Heparin-Induced Thrombocytopenia (HIT), with or without thrombosis
Anaphylaxis
Osteoporosis (with long-term use)
Hyperkalemia (due to aldosterone suppression)
Heparin-induced thrombocytopenia (0.5% incidence)
Life-threatening thrombotic complications (due to HIT)
Osteoporosis (with therapeutic doses >20,000 units/day for extended periods, e.g., 3-6 months)
Hyperkalemia
Serious thromboembolic events (due to marked depletion of platelets with antibodies to heparin-platelet complex)
Osteoporosis (on long-term use of relatively high doses)
Hypersensitivity reactions (urticaria, rigor, fever, anaphylaxis)
Heparin-induced thrombocytopenia (HIT)
Osteoporosis