Interaction: Cough and Cold Medications and Remedies

Effect from the Disease

• Hypermetabolic states produced by fever (or hyperthyroidism) increase warfarin responsiveness
• This might be probably by increasing the catabolism of vitamin K–dependent coagulation factors
• Patients taking warfarin who contract the flu are at increased risk of bleeding due to the combination of reduced appetite, fluid loss, and general stress to the body
• presence of a respiratory infection untreated by an antibiotic, as well as exposure to an antibiotic, were both associated with more than twice the likelihood of having an INR reading of 5.0 or higher

Effect from the Medications used

TRADITIONAL
PRODUCTS	INR/severity	NOTE
GARLIC	↑ / possible	decreased platelet aggregation
GINGER	↑/ probable	antiinflammatory antispasmodic, and antiplatelet activities
TUMERIC	↑/ probable	antiinflammatory
CHAMOMILE	↑/ possible
OTC
PARACETAMOL/ ACETOMINOPHEN	↑ / moderate	Not > 2g/day and for not more than a few days
SALICYLATES drugs	↑ / moderate
ASPIRIN	↑ / major	Avoid/ stop/ adjust dose
DIPHENHYDRAMINE / BENADRYL	No interactions
BROMHEXINE
CHLORPHENIRAMINE
LORATIDINE
PSEUDOEPHEDRINE

Effects from Antibiotics

Need for Adjustments

• most patients with previously stable warfarin therapy will not experience clinically relevant increases in INR following antibiotic exposure or acute upper respiratory tract infection
• BUT as the levels will fluctuate, it is necessary for more stringent monitoring of INR

References:

1. lexicomp
2. www.uptodate.com
3. Systematic Overview of Warfarin and Its Drug and Food Interactions
4. Coumadin Interactions. http://www.bjchealth.org/warfarin
5. Foundation Guide to Warfarin Therapy. http://circ.ahajournals.org/content/107/12/1692.full
6. Interactions wit Warfarin. http://www.coumadin.com/pdf/Interactions_With_COUMADIN.pdf