Direct%25252520oral%25252520anticoagulants

# Direct Oral Anticoagulants (DOACs) ## Overview Direct oral anticoagulants (DOACs) target specific coagulation factors: **Apixaban, Edoxaban, and Rivaroxaban** (Factor Xa inhibitors) and **Dabigatran** (Direct Thrombin inhibitor). They offer predictable pharmacokinetics and avoid routine coagulation monitoring compared to warfarin. ## Primary Indications * Non-valvular atrial fibrillation (stroke prophylaxis). * Treatment of acute Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). * Extended prophylaxis for recurrent DVT/PE. * Venous thromboembolism (VTE) prophylaxis post-orthopedic surgery (hip/knee replacement). ## Adult Dosing * **Apixaban (Eliquis):** * Afib: 5 mg PO BID. (Reduce to 2.5 mg BID if ≥2 of: age ≥80, weight ≤60 kg, or Scr ≥1.5 mg/dL). * DVT/PE: 10 mg PO BID for 7 days, then 5 mg BID. * **Rivaroxaban (Xarelto):** * Afib: 20 mg PO daily with evening meal. * DVT/PE: 15 mg PO BID for 21 days, then 20 mg daily with food. * **Dabigatran (Pradaxa):** * Afib: 150 mg PO BID (110 mg BID used in select EU/other populations; US often 150 mg). * DVT/PE (post-parenteral lead-in): 150 mg PO BID. * **Edoxaban (Savaysa):** * Afib: 60 mg PO daily (Do not use if CrCl >95 mL/min). * DVT/PE: 60 mg daily (post-parenteral lead-in). ## Pediatric Dosing Pediatric dosing is highly protocol-dependent and weight-based. Apixaban and Dabigatran have approved pediatric formulations/dosing for VTE treatment based on age and body surface area (BSA). Consult local institutional guidelines and specialized pediatric hematology protocols before initiation. ## Dose Adjustments * **Renal Impairment:** Mandatory dose reductions or contraindications based on CrCl. Dabigatran has the highest renal clearance (~80%); Apixaban the lowest (~27%). * **Hepatic Impairment:** Avoid or exercise caution in Child-Pugh B/C due to increased bleeding risk. ## Contraindications * Hypersensitivity to the agent. * Active pathological bleeding. * Mechanical heart valves (Dabigatran specifically contraindicated). * Moderate-to-severe hepatic impairment (varices risk). * Pregnancy/Lactation (limited data, generally contraindicated in favor of LMWH). ## Adverse Effects * Major and minor bleeding (GI bleeding is most common). * Anemia. * Dyspepsia (notably higher with Dabigatran). * Elevated liver enzymes. ## Key Drug Interactions * **P-gp and Strong CYP3A4 inhibitors/inducers:** Co-administration (e.g., ketoconazole, rifampin, phenytoin, carbamazepine) can significantly alter serum concentrations. * **Antiplatelets/NSAIDs/SSRIs:** Increased risk of major hemorrhage when combined with DOACs. ## Monitoring * **Renal Function:** Monitor CrCl at baseline and periodically (semi-annually or more frequently in elderly/renal patients). * **Adherence:** High-risk compliance; missed doses dramatically lower protection due to short half-lives. * **No routine coagulation monitoring:** Traditional INR is not useful. Specialized assays (anti-Xa for Xa inhibitors, dilute thrombin time/ECT for Dabigatran) may be ordered in emergency settings (e.g., urgent surgery or life-threatening hemorrhage). ## Clinical Pearls * **Reversal Agents:** Idarucizumab (Praxbind) for Dabigatran; Andexanet alfa (Andexxa) for Factor Xa inhibitors. * **Transitioning:** Utilize standard conversion protocols (e.g., stopping warfarin until INR <2.0 before starting DOACs). * **Surgical Hold:** Generally hold 24–48 hours for low-bleed-risk procedures; longer (up to 72+ hours) for high-bleed-risk or renal impairment. *** **Disclaimer:** This information is for educational purposes only. Always consult the most current prescribing information (package insert), your institutional drug formulary, and clinical guidelines (e.g., CHEST, ASH) before prescribing or administering medication. Confirm patient-specific renal function and contraindications prior to dosing.