Vitamin CAn Ineffective Panacea

Jake AmerineRyan Cook

Adam CoreySarah Miller Hendricks

Objectives

● Identify historical uses of vitamin C.● Outline the mechanism of action & how

it interacts with the body and other drugs.

● Compile basic safety and efficacy information on vitamin C that will be useful for pharmacists in patient interaction.

● Interpret clinical cases that illustrate contrasting conclusions on the effectiveness of vitamin C.

Foods with Vitamin C[1]

Papaya (188 mg) Bell Peppers (117 mg)

Lemon (112 mg) Lime (112 mg)

Grapefruit (88 mg) Strawberries (85 mg)

Broccoli (81 mg) Pineapple (79 mg)

Brussels Sprouts (75 mg) Kiwifruit (72 mg)

Oranges (70 mg) Cantaloupe (59 mg)

Kale (53 mg) Cauliflower (52 mg)

Why do people take Vitamin C?2

The Common Cold

Scurvy

Historical Background2,3

● 1747 - British Navyo Sailors with scurvyo Treated with Citrus Fruit

● 1937 - Nobel Prizeso Isolated Ascorbic Acid

o Szent-Gyorgi and Hayworth

● 1970’s - Linus Paulingo Vitamin C and the

Common Coldo Cancer and Vitamin C

Naming of Vitamin C2,4

Common Names Brand NamesAntiscobutic Vitamin Iso-ascorbic acid C 500 Emergen-C

Ascorbate L-ascorbic acid C 500 / Rose Hips Liquid C 500

Ascorbate de calcium

Magnesium ascorbate

C-1000 Pure C 500

Ascorbate de sodium

Selenium ascorbate C-1000 SR Pureway-C

Ascorbic acid (AA) Sodium ascorbate Fruit C TH Vitamin C

Ascorbyl palmitate Vitamina C Chew-C Yummy C

Calcium ascorbate Acido ascórbico C-Time Vitamin C RoseHips

The Basics2

● Water-Soluble vitamin

● Necessary for the formation of:

o Collagen in bones

o Cartilage

o Muscle

o Blood vessels

o Also Iron Absorption

Dosing Forms and Administration2

Orally1. Wafer – (500 mg)2. Chewable tablet – (250 mg - 500 mg)3. Tablet – (250 mg – 1000 mg)4. Extended Release tablet – (500 mg – 1500 mg)5. Extended Release Capsule6. Granules7. Powder – 1000 mg8. Liquid – 500mg/5mL9. Syrup – 500 mg / 5mL10.Lozenge – 60 mg11. Capsule – 60 mg

Injection1. Solution – 500 mg/mL

Topical1. Creams – 5 – 10% Vitamin C in anti-wrinkle creams

Chewables - 60ct - $5.32Emergen-C - 30 ct - $10.84Capsules - 100 ct - $4.37Cream - 2 fl. oz - $15.98

Dosage Limitations2

Daily Recommendation● Men ≥18, 90mg● Women ≥18, 75mg

● Adolescents 14-18 years old,

75mg for boys and 65mg for

girls

● Children 9-13 years old, 45mg

● Children 4-8 years old, 25mg

● Children 1-3 years old, 15mg

● Infants 0-12 months old,

human milk content

The Tolerable Upper Limit (TUL)● Adults greater than 18,

2,000 mg

● Adolescents 14 - 18 years of Age, 1,800 mg

● Children 9 - 13 years of Age, 1,200 mg

● Children 4 - 8 years of Age, 650 mg

● Children 1 - 3 years of Age, 450 mg

Indications2

● Vitamin C Deficiency (scurvy)

● Common Cold Prevention (extreme conditions)

● Iron Absorption enhancement

● Urinary tract infection (during pregnancy)

● other inconclusive indications…o The Common Cold

GradeAB

BB

C/D

Mechanism of Action2

● Affects bioavailability of nitric oxide during acute inflammation, including the inhibition of nitric oxide synthase induction

● Reduces hydrogen peroxide, a cofactor for connective tissue formation

Antioxidant/Immunostimulant effects:

Contraindications5

“There are no contraindications to the administration of ascorbic acid.”

However….

Warnings/Precautions6

Diabetes - don’t take excess doses for extended periods of time. Why?

Renal Calculi (i.e. Dialysis patients) - don’t take excess doses for extended periods of time. Why?

Warnings/Precautions6

Don’t take excessive doses for extended periods of time if:

-stool occult blood tests

-sodium restricted diet

-anticoagulant therapy

Interactions6

Drug-Drug Interactions:-Bortezomib

-Aluminum Hydroxide - ascorbic acid may increase the absorption of Aluminum Hydroxide

Bortezomib

Interactions6

Drug-Drug Interactions:-Cyclosporine

-Estrogen Derivatives: Ascorbic acid may increase the serum concentration of Estrogen Derivatives

Common Side Effects5,6,7

Nausea - Vomiting

Headache

Stomach Cramps

Heart Burn

Serious Side Effects5,6,7

Kidney Stones

Bleeding

Diarrhea

Dizziness and/orFainting

Sore Muscles

Trial #1: The Effects of “Megadoses” of Vitamin C8

● Background:o US Recommended Daily Allowance of Vitamin

C 75 mg for adult male 70 mg for adult female

o Some literature shows that doses much higher than these recommendations are effective in treating respiratory infections.

● Objective:o To study the effect of megadose Vitamin C in

regards to preventing & treating cold & flu symptoms

“Megadose” Trial Design8

● Participantso Control group = 463 students (age 18-32)o Test group = 252 students (age 18-30)

● Methodo To track the number of cold & flu symptoms

reported amongst the two populations.o Control group: pain relievers & decongestantso Test group:

Hourly doses of 1000 mg Vitamin C for first 6 hrs

1000 mg doses three times/day afterwards No symptoms = 1000 mg three times/day

“Megadose” Trial Results8

● On day 10 of treatment:o Test group: 0%

reported symptoms

o Control group: 8% reported symptoms

● Symptoms in test group decreased 85% compared to control group!

Trial #2: Cochrane Collaboration Review3

● Meta-Analysis of:o 29 Studies

o 11,306 participants

o 70 years

● Conclusionso No net effect on the

incidence or duration of the common cold

o Except in cases of extreme physical stress

Overall Conclusions

Would we recommend Vitamin C to patients?● No; due to its natural standard grade of D

for common cold prevention/treatment.What patient populations should not take Vitamin C?● Those taking diabetes medications or

antibiotics; pregnant women; dialysis patients

Is Vitamin C safe for OTC use?● Overall, vitamin C is a safe supplement

for if taken in reasonable doses.

Checking Your Understanding...

1. For what indication has vitamin C been shown to be most effective?

2. What is its main mechanism of action?

3. What are two groups of people that should not take vitamin C supplements?

4. From the meta-analysis, which group of people showed a 50% reduction in cold symptoms?

What questions do you have for us?

References1. Vitamin C. The World’s Healthiest Foods Website. http://www.whfoods.com/genpage.php?tname=nutrient&dbid=109, Accessed October 9, 20132. Vitamin C (ascorbic acid) Natural Standard. Professional Monograph, Copyright © 2013. http://unc.naturalstandard.com/databases/herbssupplements/vitaminc.asp?#attribution3. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2013; Issue 1. Art. No.4. Vitamin C. Drug Facts and Comparisons. Last Modified: November 2012. Copyright © 2013 by Wolters Kluwer Health, Inc. online.factsandcomparisons.com5. Ascorbic Acid [package insert]. Mylan Institutional LLC, Canonsburg, PA.; February 2010. http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d05200cb-cf29-4bc7-bf0c-b42ab2d20958#nlm34070-3. Accessed October 23, 2013.6. UpToDate. UpToDate Web site. http://www.uptodate.com/contents/search?search=ascorbic+acid&sp=0&searchType=PLAIN_TEXT&source=USER_INPUT&searchControl=TOP_PULLDOWN&searchOffset=. Accessed October 23, 20137. Natural Standard - The Authority on Integrative Medicine. Somerville, MA: Natural Standard. unc.naturalstandard.com/databases/herbssupplements/all/flashcard-vitaminc.asp. Updated October 23, 2013. Accessed October 23, 2013.8. Gorton H, Jarvis K. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections. JMPT. 1999; 22(8): 530-533. http://www.sciencedirect.com/science/article/pii/S0161475499700059. Accessed October 18, 2013.