Food – Drug Interactions:

More presentations from Naina Mohamed Pakkir Maideen

•        A Food - Drug interaction occurs when a food interferes with the effects of a drug in the body.

•        The content of certain foods interact with some drugs and produce alterations in the Pharmacokinetic (Absorption, Distribution, Metabolism and Elimination) and Pharmacodynamic (Physiologic actions) effects of the drugs.

•        Tyramine rich foods (Aged Cheese) may induce Life-threatening hypertensive reaction by interacting with Non-selective MAOIs (tranylcypromine, phenelzine etc.) or MAO-B Inhibitor (Higher dose of Selegeline). Patients taking any of the non-selective MAOIs should not eat foods containing substantial amounts of tyramine.

•        Dairy Products (Milk) reduce the absorption and therapeutic efficacy of Fluoroquinolones (Ciprofloxacin, Norfloxacin), Tetracyclines and Bisphosphonates (Alendronate, Risedronate, and Ibandronate).

•        Vitamin K Rich Foods (Kale, Collards, Spinach, Turnip greens, Mustard greens, Beet greens, Dandelion greens, Brussels sprouts and Broccoli) may interact with Warfarin and increase the risk of clot formation. Suddenly increasing or decreasing intake of Vitamin K rich foods can alter the effectiveness of the warfarin. So eat greens in consistent amounts. 

•        Potassium Rich Foods may interact with ACEIs (Lisinopril, etc), ARBs (Losartan, etc), Direct Renin Inhibitors (Aliskiren) or Potassium sparing Diuretics (Spiranolactone, etc) and increase the risk of Hyperkalemia.

•        Fiber Rich Foods may interact with Digoxin, Amoxicillin, Levothyroxine or TCAs (Doxepin and Desipramine) and delay their absorption. Avoid ingesting high-fiber foods concomitantly.  

•        Protein Rich Foods may increase the bioavailability of Propranolol.

•        High Fat Meals may elevate the plasma levels of Griseofulvin. Patients should be instructed to take griseofulvin after a high-fat content meal.

•        Fruit juices like Grapefruit juice (GFJ), Apple juice or Orange juice may reduce the therapeutic efficacy of Fexofenadine.

•         Grapefruit juice (GFJ) may interact with CYP3A4 substrates such as Simvastatin, Amiodarone, Erythromycin, Apixaban, etc. and increase the risk of their toxic effects.

•        Seville orange juice may interact with CYP3A4 substrates like Colchicine, etc. and increase the risk of toxic effects.

•        Orange juice may interact with drugs like Fexofenadine, Atenolol or Fluoroquinolones and reduce their therapeutic efficacy.

•        Apple juice may reduce the therapeutic efficacy of Fexofenadine or Atenolol.

•        Licorice may decrease the effectiveness of Antihypertensives such as Amlodipine, Aliskiren, Valsartan, Captopril, Carvedilol, etc. The people with high blood pressure, heart failure, pulmonary hypertension or kidney disease should avoid or limit the consumption of licorice.

•        Fish (Omega-3 fatty acids) may increase the risk of Bleeding by interacting with drugs like Anticoagulant / Antiplatelet drugs (Aspirin, Clopidogrel, Ticlopidine, Dipyridamole, Alteplase, Dalteparin, Enoxaparin, Heparin, warfarin and others). It is recommended to consult the physician when the patients experience any unusual bleeding or bruising, swelling, vomiting, blood in your urine or stools, headache, dizziness, or weakness during treatment with these medications.

•        Pharmacist or physician should determine the clinical relevance of the interactions of drugs with certain foods or beverages and advise patients appropriately.

Drug Interactions of OTC Decongestants:

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ª  Pseudoephedrine is an oral OTC decongestant available commonly.

ª  Oxymetazoline and Xylometazoline are topical OTC decongestants and are available as nasal drops or nasal sprays.

ª  Concomitant use of Pseudoephedrine and
MAO Inhibitors such as Selegiline, Rasagiline, Clorgyline, Pargyline, Toloxatone, Iproniazid, Moclobemide, Nialamide, Procarbazine, Phenelzine , Isocarboxazid, Tranylcypromine, Furazolidone is contraindicated, due to elevated risk of hypertensive crisis characterized by hypertension, hyperpyrexia and headache.

ª  It is contraindicated to use Pseudoephedrine and Linezolid concomitantly, due to increased blood pressure.

ª  Co-administration of Pseudoephedrine and Dihydroergotamine is contraindicated, due to extreme elevation of blood pressure.

ª  The blood pressure control of Guanethidine and Methyldopa is lost due to concomitant use of Pseudoephedrine.

ª  Bitter orange contains synephrine which can interact with Pseudoephedrine and increase the risk of hypertensive crisis.

ª  Topical decongestants (Oxymetazoline or Xylometazoline) increase the risk of hypertensive crisis by interacting with MAO Inhibitors.

ª  Pseudoephedrine should be avoided during pregnancy, if possible.

ª  People with heart disease, high blood pressure, diabetes, hyperthyroidism and enlarged prostate should consult a doctor or pharmacist before they take decongestants because side effects can be dangerous.

ª  Physicians should be aware of potential drug interactions with OTC medicines when prescribing new medications.

ª  Pharmacists can be instrumental in assisting patients with using OTC medications safely and effectively.

ª  Pharmacists should warn consumers of the risks of misusing OTC pain relievers.

Drug Interactions of OTC Antihistamines (Part 2):

Drug Interactions of Second Generation Antihistamines:

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·      Second generation OTC Antihistamines include Loratadine, Cetirizine and Fexofenadine.

·      Amiodarone may elevate the risk of “Torsades de pointes” by blocking CYP3A4 induced metabolism of Loratadine.

·      P-glycoprotein (P-gp) inhibitors such as Tocofersolan, Nilotinib, Lomitapide and Simeprevir block the P-glycoprotein-mediated efflux transport of Fexofenadine and increase the plasma levels of Fexofenadine.

·      Amiodarone also increase the plasma levels of Fexofenadine by blocking CYP enzymes induced metabolism and P-glycoprotein efflux transport of Fexofenadine.

·      Fruit Juices like Grapefruit juice, Orange juice and Apple juice decrease the effectiveness of fexofenadine by inhibiting organic anion transporting polypeptide (OATP).

·       Patients should thoroughly read the labels of all over-the-counter and prescription medicines.

·      Patients should talk to their doctor or pharmacist before taking any new prescription or over the counter medication.

·      Physicians should be aware of potential drug interactions with OTC medicines when prescribing new medications.

·      Pharmacists can be instrumental in assisting patients with using OTC medications safely and effectively.

·      Pharmacists should warn consumers of the risks of misusing OTC pain relievers.

Drug Interactions of OTC Antihistamines (Part 1):

Drug Interactions of First Generation Antihistamines:

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§  First-Generation OTC Antihistamines include Brompheniramine, Chlorpheniramine, Dimenhydrinate, Diphenhydramine, and Doxylamine.

§  The risk of serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes) is elevated by the concomitant administration of Brompheniramine or Chlorpheniramine with Antidepressants (SSRIs, SNRIs, TCAs, Trazodone, Vortioxetine, Amoxapine) or serotonergic drugs (Lorcaserin, Almotriptan, Hydroxytryptophan, Fentanyl and Tramadol).

§  Excessive anticholinergic activity (severe dry mouth, constipation, decreased urination, excessive sedation, blurred vision) may resulted due to combination of Chlorpheniramine or Diphenhydramine and drugs having anticholinergic activity (Belldonna, Clomipramine, Amitriptyline, Triflupromazine, amoxapine and Linezolid).

§  Coadministration of Diphenhydramine and Opioids (Hydromorphone, Oxycodone, Hydrocodone, Fentanyl, Tapentadol), Other CNS depressants (Zolpidem, Loxapine, Meclizine, Carbinoxamine) or Ethanol increase the risk of CNS depression.

§  The American Congress of Obstetricians and Gynecologists (ACOG) and the American College of Allergy, Asthma and Immunology (ACAAI) recommend Chlorpheniramine as the antihistamine of choice during pregnancy.

§  According to the World Health Organization, use of chlorpheniramine in nursing mothers should be avoided if possible.

§  Patients should thoroughly read the labels of all over-the-counter and prescription medicines.

§  Patients should talk to their doctor or pharmacist before taking any new prescription or over the counter medication.

§  Physicians should be aware of potential drug interactions with OTC medicines when prescribing new medications.

§  Pharmacists can be instrumental in assisting patients with using OTC medications safely and effectively.

§  Pharmacists should warn consumers of the risks of misusing OTC drugs.

Drug Interactions of OTC Analgesics (Part 5):

Drug Interactions of Naproxen:

More presentations from Naina Mohamed Pakkir Maideen

ü Naproxen is a Non-Steroidal Anti-inflammatory drug (NSAID) and is available as an OTC analgesic drug.

ü Naproxen is commonly used for the reduction of pain, fever, inflammation and stiffness caused by conditions including migraine, osteoarthritis, kidney stones, rheumatoid arthritis, psoriatic arthritis, gout, ankylosing spondylitis, menstrual cramps, tendinitis and bursitis.

ü Concomitant use of Ketorolac and Naproxen is contraindicated due to cumulative risks of inducing serious NSAID-related adverse events (peptic ulcers, gastrointestinal bleeding and/or perforation).

ü Bleeding risk is elevated by the coadministration of Naproxen with drugs such as Warfarin, Heparin, Low Molecular Weight Heparins (LMWHs) (Enoxaparin, Dalteparin, Tinzaparin, etc.), Coumarins and other anticoagulants (Acenocoumarol, Dicumarol, Phenprocoumon, Dabigatran, Anisindione, Phenindione), Direct thrombin inhibitors (Dabigatran, Desirudin, Lepirudin, Bivalirudin, Argatroban), Direct factor Xa inhibitors (Apixaban, Rivaroxaban), Antiplatelets (Clopidogrel, Aspirin, Prasugrel, Ticagrelor, Ticlopidine, Dipyridamole, Abciximab, Eptifibatide, Tirofiban), Danaparoid, Fondaparinux, Selective serotonin reuptake inhibitors (SSRIs) (Escitalopram, Fluvoxamine, Paroxetine, Vortioxetine,  Sertraline, Nefazodone, vilazodone), Selective serotonin and norepinephrine reuptake inhibitors (SNRIs) (Venlafaxine, Desvenlafaxine, Duloxetine, Milnacipran, Levomilnacipran, Sibutramine), Cilostazol, Protein C, Pentoxyfilline, Ginkgo, Meadowsweet, Erlotinib and Gossypol.

ü Plasma concentration of Naproxen is reduced by the administration of drugs such as Dabrafenib and Elvitegravir which induce the CYP2C9 mediated Naproxen metabolism.

ü The drugs like Mifepristone and Sulfamethoxazole elevated plasma levels of Naproxen by inhibiting CYP2C9 mediated Naproxen metabolism.

ü Use of Naproxen in patients taking ACE Inhibitors (Captopril, Enalapril, Imidapril, Temocapril, Delapril, Ramipril, Perindopril, Cilazapril), Angiotensin II receptor blockers (ARBs) (Losartan, Valsartan, Telmisartan), Beta adrenergic blockers, Calcium Channel Blockers, Thiazide Diuretics and Loop Diuretics may decrease the antihypertensive effects by decreasing renal prostaglandin production.

ü Naproxen can decrease the renal prostaglandin synthesis and increase the toxicity of Cyclosporine, Tacrolimus and Lithium.

ü The toxicity of Methotrexate, Pralatrexate and Premetrexed may be elevated by the concomitant use of Naproxen, due to decreased clearance.

ü Concomitant use of Naproxen and Fluoroquinolones (Ofloxacin, Levofloxacin, Norfloxacin) may elevate the risk of seizures.

ü Tobacco smoke contains Polycyclic aromatic hydrocarbons (PAHs) which can stimulate CYP1A2-mediated metabolism of Naproxen and reduce its plasma concentration.

ü Due to the risk of earlier closure of ductus arteriosus, Naproxen should be avoided after 30 weeks of gestation in Pregnant women.

ü Patients should thoroughly read the labels of all over-the-counter and prescription medicines.

ü Patients should talk to their doctor or pharmacist before taking any new prescription or over the counter medication.

ü Physicians should be aware of potential drug interactions with OTC medicines when prescribing new medications.

ü Pharmacists can be instrumental in assisting patients with using OTC medications safely and effectively.

ü Pharmacists should warn consumers of the risks of misusing OTC pain relievers.