Is it safe to give Amoxicillin/Clavulanate, Azithromycin, Oseltamivir, Dextromethorphan + Guaifenesin, Paracetamol, and Mometasone (nasal spray) to a cardiac patient with Ischemic Heart Disease (IHD) and recent Coronary Artery Bypass Graft (CABG) on dual antiplatelet therapy?

Safety of Medications in Post-CABG Patient on Dual Antiplatelet Therapy

All the medications listed—Amoxicillin/Clavulanate, Azithromycin, Oseltamivir, Dextromethorphan + Guaifenesin, Paracetamol, and Mometasone nasal spray—can be safely administered to this cardiac patient with recent CABG on dual antiplatelet therapy (DAPT) and Concor (bisoprolol), with specific precautions for azithromycin and paracetamol.

Dual Antiplatelet Therapy Context

Your patient is appropriately on DAPT following recent CABG, which is the standard of care:

• DAPT (aspirin + clopidogrel) for 12 months post-CABG is recommended for patients with IHD, as this reduces major adverse cardiovascular events by 35% compared to aspirin alone (HR 0.65,95% CI 0.55-0.77) without significantly increasing major bleeding risk 1
• The default DAPT duration after CABG is 12 months, though 6 months may be considered in high bleeding risk patients 2
• Clopidogrel is the preferred P2Y12 inhibitor in this setting, which your patient appears to be receiving 2

Medication-Specific Safety Assessment

Antibiotics: Amoxicillin/Clavulanate and Azithromycin

Amoxicillin/Clavulanate is safe with no significant interactions with antiplatelet agents or beta-blockers 3

Azithromycin requires caution but can be used:

• Azithromycin may potentiate the effects of oral anticoagulants, though this is less relevant for antiplatelet therapy 3
• Monitor for QT prolongation when combining azithromycin with beta-blockers (Concor), particularly in patients with cardiac disease 3
• No dose adjustment is needed, but avoid concurrent use of other QT-prolonging agents 3
• The interaction risk is primarily theoretical in the context of antiplatelet therapy rather than anticoagulation 3

Antiviral: Oseltamivir

Oseltamivir is safe with no documented interactions with antiplatelet agents or beta-blockers, and no specific cardiac contraindications exist for post-CABG patients 4

Cough Medications: Dextromethorphan + Guaifenesin

This combination is safe with no significant interactions with DAPT or beta-blockers 4

Analgesic/Antipyretic: Paracetamol (Acetaminophen)

Paracetamol can be used but requires monitoring:

• Use the lowest effective dose for the shortest duration (maximum 2-3 grams daily rather than 4 grams) 2
• Avoid chronic high-dose use as paracetamol may enhance antiplatelet effects and increase bleeding risk when combined with DAPT 2
• Short-term use (3-5 days) at standard doses is generally safe 4
• This is preferable to NSAIDs, which are contraindicated due to increased cardiovascular and bleeding risks in post-CABG patients on DAPT 4

Nasal Spray: Mometasone

Mometasone nasal spray is safe with no systemic interactions with cardiac medications or antiplatelet therapy due to minimal systemic absorption 4

Critical Safety Considerations

Bleeding Risk Management

• Add or continue a proton pump inhibitor (PPI) for gastrointestinal protection while on DAPT, especially when adding multiple medications that may affect hemostasis 2
• Avoid NSAIDs entirely, as they significantly increase bleeding risk and cardiovascular events in patients on DAPT 2
• Monitor for signs of bleeding (melena, hematuria, excessive bruising) 2

Drug Interaction Monitoring

• Avoid aluminum- and magnesium-containing antacids if using azithromycin, as they reduce azithromycin absorption 3
• Continue Concor (bisoprolol) without interruption unless hemodynamically unstable 2
• The combination of multiple medications increases polypharmacy risk, which accounts for 10.6% of ED visits in elderly cardiac patients 4

Cardiac-Specific Precautions

• Monitor for QT prolongation if using azithromycin, particularly given the underlying cardiac disease and concurrent beta-blocker use 3
• Ensure adequate hydration, especially if fever is present, to maintain cardiac output and prevent hypotension with beta-blocker therapy 2
• Watch for signs of heart failure exacerbation (dyspnea, edema, orthopnea) as respiratory infections can precipitate decompensation 2

Practical Management Algorithm

1. Initiate antibiotic therapy (choose either Amoxicillin/Clavulanate OR Azithromycin, not both unless specifically indicated) 3
2. Add oseltamivir if influenza is confirmed or highly suspected within 48 hours of symptom onset 5
3. Use paracetamol at reduced doses (500-1000 mg every 6-8 hours, maximum 3 grams daily) for fever/pain control 2
4. Provide symptomatic relief with Dextromethorphan + Guaifenesin for cough 4
5. Continue mometasone nasal spray for nasal congestion 4
6. Ensure PPI is prescribed if not already on one 2
7. Continue DAPT and Concor without interruption 2

Common Pitfalls to Avoid

• Do not discontinue DAPT for this acute illness unless life-threatening bleeding occurs 2
• Do not use NSAIDs for pain/fever control—paracetamol is the only acceptable option 2, 4
• Do not combine multiple antibiotics without clear indication, as this increases adverse event risk 3
• Do not use high-dose paracetamol chronically (>3 grams daily for >5 days) due to potential enhancement of antiplatelet effects 2