What are the potential interactions between my medications?

Medication Interaction Assessment

I cannot provide a comprehensive interaction analysis without knowing which specific medications you are taking. However, I can guide you through the critical interaction categories you need to evaluate based on the evidence provided.

Critical Drug Interaction Categories to Check

Life-Threatening Interactions (Absolute Contraindications)

Sofosbuvir-based regimens with amiodarone are absolutely contraindicated due to risk of life-threatening bradycardia and arrhythmias, with one reported fatal case. 1 Bradycardia can occur within hours to days, but cases have been observed up to 2 weeks after starting treatment. 1

High-Risk Cardiovascular Combinations

• Lisinopril with lithium increases lithium levels and toxicity, requiring close monitoring of lithium levels. 2
• Bosentan with amiodarone or fluconazole considerably increases bosentan levels and is potentially contraindicated. 1
• Warfarin interactions require intensive monitoring when combined with:
  • Sitaxentan (requires 80% warfarin dose reduction) 1
  • Bosentan (increases warfarin metabolism) 1
  • TMP-SMX (increases bleeding risk) 1
  • Macrolide antibiotics except azithromycin (increases bleeding risk) 1

Serotonin Syndrome Risk

Avoid combining multiple serotonergic agents, particularly MAOIs (phenelzine, isocarboxazid, moclobemide, isoniazid, linezolid) with SSRIs, SNRIs, TCAs, tramadol, dextromethorphan, or stimulants. 1 Vyvanse (lisdexamfetamine) with mirtazapine may lead to serotonin syndrome and cardiovascular effects. 2

Central Nervous System Depression

Avoid concurrent use of opioids with benzodiazepines or gabapentinoids (except when transitioning from opioids to gabapentinoids). 1 Concurrent use of three or more CNS agents (antidepressants, antipsychotics, benzodiazepines, nonbenzodiazepine hypnotics, antiepileptics, opioids) increases fall risk. 1

Antibiotic-Specific Interactions

• Ciprofloxacin with theophylline increases theophylline toxicity risk. 1
• TMP-SMX with phenytoin increases phenytoin toxicity risk. 1
• TMP-SMX with ACE inhibitors or ARBs in patients with reduced kidney function increases hyperkalemia risk. 1

Hepatitis C Direct-Acting Antivirals

Sofosbuvir should not be administered with P-glycoprotein inducers: rifampin, carbamazepine, phenytoin, or St. John's wort, as these significantly decrease sofosbuvir concentrations and may lead to treatment failure. 1

Bosentan interactions include:

• Cyclosporine: contraindicated (cyclosporine levels fall 50%, bosentan levels increase 4-fold) 1
• Glibenclamide: contraindicated (increased aminotransferases, decreased hypoglycemic effect) 1
• Hormonal contraceptives: unreliable contraception due to decreased hormone levels 1

Hyperkalemia Risk

Avoid combining medications that increase serum potassium, particularly TMP-SMX with ACE inhibitors or ARBs in patients with reduced kidney function. 1

Monitoring Recommendations

• Blood pressure monitoring is essential for patients on lisinopril, especially when combined with stimulants like Vyvanse. 2
• Regular medication reconciliation should be performed to identify drug therapy problems and assess adherence. 2
• Lithium levels require close monitoring when combined with ACE inhibitors like lisinopril. 2

Next Steps

To receive a specific interaction analysis, you must provide your complete medication list including prescription drugs, over-the-counter products, supplements, and herbals with their dosages. 3 Patients who cannot identify their medications by name (relying only on visual characteristics) have significantly worse adherence, lower blood pressure control, and greater hospitalization risk. 4