Heparins

Heparins

Drug monograph · NCLEX study reference
Therapeutic class	Anticoagulant
Pharmacologic class	Heparins and factor Xa inhibitor (fondaparinux)
Onset / peak / duration	IV unfractionated immediate; SubQ enoxaparin within hours.
Half-life / level	Unfractionated short (titrated by aPTT or anti-Xa); enoxaparin longer (monitoring usually not needed except in renal impairment, obesity, or pregnancy).
Routes	IV, SubQ
High-alert (ISMP)	Yes
Black box warning	Yes (see Safety)
Antidote / reversal	Protamine sulfate (fully reverses unfractionated heparin, partially reverses low-molecular-weight heparin); no good reversal for fondaparinux.
Pregnancy / lactation	Heparins are preferred anticoagulants in pregnancy (do not cross the placenta).

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Heparins — Anticoagulant; Heparins and factor Xa inhibitor (fondaparinux).

Identification

• Therapeutic class: Anticoagulant.
• Pharmacologic class: Heparins and factor Xa inhibitor (fondaparinux).

Pharmacology

• Mechanism of action: Activate antithrombin to inhibit thrombin and factor Xa (unfractionated affects both; low-molecular-weight heparins and fondaparinux mainly factor Xa).
• Onset / peak / duration: IV unfractionated immediate; SubQ enoxaparin within hours.
• Half-life / therapeutic level: Unfractionated short (titrated by aPTT or anti-Xa); enoxaparin longer (monitoring usually not needed except in renal impairment, obesity, or pregnancy).

Clinical use

• Indications: Venous thromboembolism treatment and prophylaxis, acute coronary syndrome, bridging anticoagulation.
• Usual dose, route, frequency: Unfractionated IV infusion or SubQ; enoxaparin SubQ once or twice daily by weight.
• Maximum dose / adjustments: Reduce low-molecular-weight heparins in renal impairment; weight-based dosing.

Safety

• Contraindications: Active major bleeding, history of heparin-induced thrombocytopenia, severe thrombocytopenia.
• Black box warning: Low-molecular-weight heparins and fondaparinux carry a boxed warning for spinal or epidural hematoma with neuraxial anesthesia or spinal puncture, which can cause long-term or permanent paralysis.
• Interactions: Other anticoagulants and antiplatelets and NSAIDs (bleeding).
• Pregnancy / lactation: Heparins are preferred anticoagulants in pregnancy (do not cross the placenta).
• High-alert: Yes.

Adverse effects

• Common side effects: Bruising, injection-site reactions, minor bleeding.
• Serious effects to report: Major bleeding, heparin-induced thrombocytopenia (falling platelets with new clots), spinal hematoma signs.
• Antidote / reversal: Protamine sulfate (fully reverses unfractionated heparin, partially reverses low-molecular-weight heparin); no good reversal for fondaparinux.

Nursing process

• Assessment before administration: Baseline CBC and platelets, aPTT (unfractionated), bleeding risk, renal function.
• Interventions during therapy: Do not aspirate or rub SubQ injections; give enoxaparin in the abdomen and rotate sites; do not expel the air bubble in prefilled syringes; monitor platelets for heparin-induced thrombocytopenia.
• Monitor: aPTT or anti-Xa (unfractionated), platelets, signs of bleeding, hemoglobin.
• Evaluation / expected outcome: Therapeutic anticoagulation without bleeding.

Patient teaching

• Patient teaching: Report bleeding or bruising; rotate self-injection sites; do not rub the site.
• Notify provider if: Unusual bleeding, black stools, new swelling or clot signs, back pain with weakness.
• Administration tips: SubQ in the abdomen, do not rub; IV unfractionated requires aPTT monitoring; high-alert double-check.