INNOHEP
Clinical safety rating: caution
Comprehensive clinical and safety monograph for INNOHEP (INNOHEP).
Tinzaparin is a low molecular weight heparin that binds to antithrombin III, accelerating its inhibition of factor Xa and thrombin (factor IIa), thereby exerting anticoagulant effects.
| Metabolism | Tinzaparin is primarily metabolized in the liver via desulfation and depolymerization, with some involvement of renal excretion of lower molecular weight fragments. |
| Excretion | Primarily renal; 40-50% of the dose excreted unchanged in urine; minor biliary/fecal elimination. |
| Half-life | Terminal half-life 3-4 hours; clinical context: once-daily dosing provides sustained anti-Xa activity. |
| Protein binding | 90% bound to antithrombin III. |
| Volume of Distribution | 0.15-0.25 L/kg; reflects limited extravascular distribution consistent with high protein binding. |
| Bioavailability | Subcutaneous: 90-100%. |
| Onset of Action | Subcutaneous: 1-2 hours for peak anti-Xa activity; immediate effect if given IV (not standard). |
| Duration of Action | Approximately 12-18 hours; clinical note: once-daily SC dosing maintains therapeutic levels. |
Subcutaneous administration: 2500 IU anti-Xa (0.25 mL) once daily for low to moderate risk of thromboembolism; 3500 IU anti-Xa (0.35 mL) once daily for high risk. For treatment of deep vein thrombosis (DVT): 175 IU anti-Xa/kg body weight once daily by subcutaneous injection. Maximum dose: 17,500 IU per day.
| Dosage form | INJECTABLE |
| Renal impairment | For CrCl 30-50 mL/min: dose reduction by 25%; CrCl <30 mL/min: dose reduction by 50% and monitor anti-Xa activity. Alternative: avoid use if CrCl <30 mL/min. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: use with caution, consider dose reduction; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for use in children due to lack of safety and efficacy data. Consider alternative low molecular weight heparins with established pediatric dosing. |
| Geriatric use | Elderly patients (age ≥75 years) may have reduced renal function; dose should be based on renal function (see renal adjustment). Caution as increased risk of bleeding, especially with body weight <45 kg. Consider anti-Xa monitoring. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for INNOHEP (INNOHEP).
| Breastfeeding | Tinzaparin is not excreted into breast milk in significant amounts due to high molecular weight. M/P ratio not established; expected to be low. Considered compatible with breastfeeding by most authorities. |
| Teratogenic Risk | Innohep (tinzaparin) is a low molecular weight heparin. No evidence of teratogenicity in animal studies. Human data limited; risk of fetal hemorrhage or teratogenicity is low. Use during pregnancy only if clearly needed. First trimester: minimal risk. Second and third trimesters: increased risk of bleeding, but no structural teratogenic effects reported. |
■ FDA Black Box Warning
Epidural or spinal hematomas may occur in patients anticoagulated with low molecular weight heparins or heparinoids who receive neuraxial anesthesia or undergo spinal puncture. These hematomas may result in long-term or permanent paralysis. Consider monitoring for signs and symptoms of neurological impairment and urgent treatment if suspected.
| Serious Effects |
["History of heparin-induced thrombocytopenia (HIT) or heparin-induced thrombocytopenia with thrombosis (HITT)","Active major bleeding","Known hypersensitivity to tinzaparin, heparin, or pork products","Concurrent use of neuraxial anesthesia or spinal puncture (relative; requires caution)","Severe uncontrolled hypertension"]
| Precautions | ["Risk of hemorrhage: monitor for signs of bleeding","Thrombocytopenia: risk of heparin-induced thrombocytopenia (HIT)","Use with caution in patients with renal impairment (creatinine clearance <30 mL/min) as exposure may be increased","Do not administer intramuscularly due to risk of hematoma","Monitor anti-factor Xa activity in patients with severe renal impairment, obesity, or during pregnancy"] |
| Food/Dietary |
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| Fetal Monitoring |
| Monitor maternal platelet counts for heparin-induced thrombocytopenia (HIT). Monitor for signs of bleeding. Fetal monitoring per standard obstetric care; no specific fetal monitoring required for tinzaparin. |
| Fertility Effects | No known effect on fertility in animal studies. Human data lacking; unlikely to impact fertility. |
| No specific food interactions. Avoid excessive consumption of vitamin K-rich foods (e.g., leafy greens) if also on warfarin; not required with Innohep alone. Limit alcohol intake as it may increase bleeding risk. |
| Clinical Pearls | Use anti-Xa monitoring in patients with renal impairment (CrCl <30 mL/min) or extremes of body weight. Innohep (tinzaparin) has a higher molecular weight than other LMWHs, leading to a longer half-life and potential for accumulation in renal failure. Avoid in patients with heparin-induced thrombocytopenia (HIT) history. Protamine sulfate partially reverses effect (up to 60%). Monitor platelets periodically due to risk of HIT. |
| Patient Advice | Do not stop or change dose without consulting your doctor. · Report any signs of unusual bleeding or bruising, black/tarry stools, or blood in urine. · Avoid aspirin, NSAIDs, or other blood thinners unless prescribed. · Use electric razor and soft toothbrush to minimize bleeding risk. · Seek immediate medical help if you experience severe headache, vision changes, or signs of allergic reaction. · Do not rub injection site; rotate sites (abdomen, thigh, upper arm). · Keep a record of injection dates and times. |