Direct%2525252520oral%2525252520anticoagulants

# Direct Oral Anticoagulants (DOACs) ## Overview Direct oral anticoagulants (DOACs) consist of direct thrombin inhibitors (dabigatran) and Factor Xa inhibitors (apixaban, rivaroxaban, edoxaban). They offer predictable pharmacokinetics, no routine coagulation monitoring, and fewer dietary interactions compared to warfarin. ## Primary Indications * Non-valvular atrial fibrillation (stroke/systemic embolism prophylaxis). * Treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE). * Prophylaxis of DVT/PE following hip or knee replacement surgery. ## Adult Dosing * **Apixaban:** 5 mg PO BID. Reduce to 2.5 mg BID if ≥2 of the following: Age ≥80, weight ≤60 kg, or Scr ≥1.5 mg/dL. For VTE treatment: 10 mg BID for 7 days, then 5 mg BID. * **Rivaroxaban:** 20 mg PO daily (with evening meal). For VTE treatment: 15 mg BID for 21 days, then 20 mg daily. Max dose for AFib: 20 mg daily. * **Dabigatran:** 150 mg PO BID. (Adjust to 75 mg BID if CrCl 15–30 mL/min). * **Edoxaban:** 60 mg PO daily. (Adjust to 30 mg daily if CrCl 15–50 mL/min). * *Note: Dosing can vary by institution; always consult local institutional protocols or guidelines.* ## Pediatric Dosing Pediatric dosing is weight-based and highly specialized. **Dabigatran** is FDA-approved for pediatric patients (age 3 months to <18 years) for VTE, typically dosed via nomogram based on body surface area or weight. Apixaban and rivaroxaban uses in pediatrics are often off-label or based on institutional trial protocols. **Consult a pediatric hematologist or specialized institutional dosing guide before administration.** ## Dose Adjustments * **Renal Impairment:** Mandatory dose adjustments based on CrCl for all DOACs. Avoid use in patients with CrCl <15 mL/min or those on dialysis (except limited apixaban use in dialysis per specific institutional guidelines). * **Hepatic Impairment:** Avoid or exercise extreme caution in Child-Pugh B or C. ## Contraindications * Active pathological bleeding. * Mechanical prosthetic heart valves (dabigatran contraindicated; others may be harmful). * Moderate-to-severe mitral stenosis. * Hypersensitivity to the specific agent. ## Adverse Effects * Major and minor bleeding (GI bleeding, intracranial hemorrhage, epistaxis). * Anemia. * Dyspepsia (notably with dabigatran due to tartaric acid core). ## Key Drug Interactions * **Strong Dual Inhibitors/Inducers:** DOACs are P-gp and/or CYP3A4 substrates. Avoid strong dual inhibitors (e.g., ketoconazole, ritonavir) or strong inducers (e.g., rifampin, carbamazepine, St. John's wort) as they significantly alter exposure and bleed/clot risk. ## Monitoring * **Baseline:** CBC, baseline coagulation profile (PT/INR/aPTT - note these are insensitive), Scr, baseline LFTs. * **Ongoing:** Periodically assess renal function (CrCl) and hemoglobin/hematocrit. Evaluate adherence frequently. Routine monitoring of drug levels (e.g., anti-Xa levels for rivaroxaban/apixaban) is generally not recommended, except in emergencies or special clinical circumstances. ## Clinical Pearls * **Reversal:** Idarucizumab is a reversal agent for dabigatran. Andexanet alfa is used for apixaban and rivaroxaban. * **Dabigatran Storage:** Keep in original bottle to maintain stability and prevent degradation. * **Transitioning:** Utilize standard bridging protocols (e.g., "criss-cross" method) when switching from warfarin or parenteral anticoagulants. *** *Disclaimer: This information is for educational purposes and does not constitute medical advice. Always verify current prescribing information, institutional protocols, and patient-specific factors via reliable clinical databases (e.g., Lexicomp, UpToDate) before prescribing or administering medication.*