Grapefruit Juicy Details on Health Benefits and Drug Interactions

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Grapefruit Juicy Details on Health Benefits
and Drug Interactions
Elaine Turner Gail Rampersaud, FSHN
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Grapefruit JuiceInteractions with Prescription
Drugs

• R. Elaine Turner, PhD, RD
• FSHN Department
• University of Florida

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Grapefruit Juice Whats the Story?
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Grapefruit Juice Whats the Story?
Sex, drugs, and grapefruit
Some pills become too potent when you drink
grapefruit juice
Grapefruit juice and drugs dont mix
Forbidden Fruit? Grapefruit Juice-Medicine
Interaction Studied
Grapefruit Takes the Defense
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Food/Drug Interactions

• Food can affect
• absorption
• utilization
• excretion
• Influence can be
• positive
• negative

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Effects of Grapefruit Juice

• Enhances Absorption
• inhibits an intestinal enzyme
• less metabolism in GI tract
• first-pass metabolism
• like giving larger dose
• larger effect of drug
• Increased risk for side effects

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Normal Drug Metabolism
ORAL DOSE
GI TRACT
ENZYME
LIVER
BLOOD
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Effect of Grapefruit Juice
ORAL DOSE
GI TRACT
ENZYME
LIVER
BLOOD
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Effects of Grapefruit Juice

• Enzyme Inhibition
• one of cytochrome P450 enzymes
• CYP3A
• minimal to no effect in liver

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Effects of Grapefruit Juice

• Are All Drugs Affected? no!
• oral medications only
• low bioavailability
• first-pass metabolism by CYP3A in GI tract
• amount of effect varies
• individuals, medications

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Effects of Grapefruit Juice

• Which Types of Drugs are Affected?
• Antihypertensives
• Immunosuppressants
• Statins
• Anti-anxiety, Antidepressants
• Antihistamines
• HIV/AIDS protease inhibitors

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Effects of Grapefruit Juice

• Which Types of Drugs are Affected?
• Usually an alternative drug is available
• e.g., Pravachol instead of Lipitor

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Consumer Actions

• Ask Pharmacist
• Is my medication affected by grapefruit juice?
• Yes talk with MD before making changes
• No no need to worry

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Consumer Actions

• Ask Physician
• Is there an alternative medication I can take?

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Take Home Message

• Media Statements
• Usually too general
• Talk with pharmacist and physician
• May not need to avoid grapefruit juice

Grapefruit juice and drugs dont mix