Drug Interactions

Indication

A reason to use a certain treatment

ex. Fluconazole is an indication to treat a yeast infection

Contraindication

A reason to NOT use a certain treatment

ex. Viagra is contraindicated in men taking nitrates- risk of hypnosis

Addition

The combined effect of 2 drugs is EQUAL to the sum of each drug taken alone; taking 2 drugs that have the same purpose

Antagonism

The action of one drug antagonizes (blocking or working against the action of another drug

Potentiation

One drug ENHANCES or prolongs the effect of another drug

Synergism

The combined effect of 2 drugs is greater than the sum of effect of 2 drugs 2+2=5

Drug Disease Interactions-Pseudoephedrine

Can raise BP due to its vasoconstrictive effect

Drug Disease Interactions- Laxatives

Can cause dehydration and electrolyte imbalances posing a risk for acute kidney injury

Drug Nutrient Interactions- Grapefruit Juice

Co administered with cholesterol lowering drugs can decrease the bodies ability to metabolize leading to excess amount of drug in bloodstream

Drug Nutrient Interactions- Leafy greens

Can reduce blood thinning effects of Warfarin

Dairy

Can interact with medications by preventing absorption

• Bisphosphonates- alendronate

• Fluoroquinolone Antibiotics- Ciprofloxacin

• Levothyroxine

Drug Herbal Interactions- Gingko Biloba supplement

Increases risk of bleeding if co administered with an NSAID

Drug herbal Interactions- St. Johns Worts

Used to treat depression; increases adverse effects of several antidepressants

Drug Alcohol Interactions- Metronidazole

Can cause severe vomiting

Drug alcohol Interactions- Opioid Analgesics

Can cause excessive sedation respiratory depression, coma or death