Clinical C 100t
Orthoplex
Orthoplex Clinical C provides targeted, specialised nutrients to regenerate Vitamin C and provide longer lasting therapeutic benefits.
This product has been batch tested by HASTA for over 250 WADA prohibited substances. HASTA is the Australian sports supplement drug testing specialist, a division of Racing Analytical Services Limited (RASL), Australia's largest independent sports drug testing laboratory.





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Product Details
- Contains synergistic ingredients that support the optimal health and function of the immune system.
- Contains ingredients that play a role in glutathione peroxidase and glutathione regeneration, and therefore help reduce oxidative stress.
- Contains ingredients that are involved in the production of energy in the body.
- Contains sustainably derived mixed tocotrienols and tocopherols, representing the complete eight isomer forms of Vitamin E.
Pack Size
63 Tablet
Adult Dose
Take 1-2 tablets once or twice daily, or as recommended by your healthcare practitioner
Storage
Store below 25°C in a cool, dry place away from direct sunlight.
Indications
Excipients
Microcrystalline cellulose, calcium hydrogen phosphate dihydrate, croscarmellose sodium, macrogol 400, EvNolMax, colloidal anhydrous silica, ascorbyl palmitate, Hypromellose, Carnauba Wax.
Warning
Keep out of reach of children. This health supplement is not be used as a substitute for a varied diet. This product is Exclusively a HEALTH SUPPLEMENT and NOT INTENDED TO DIAGNOSE, TREAT, CURE OR CORRECT ANY DISEASE. This product contains selenium which is toxic in high doses. A daily dose of 150mcg for adults of selenium from dietary supplements should not be exceeded. Adults only. Not recommended for use by pregnant and lactating women. The maximum recommended dose (4 tablets) contains 220mg sodium.
Each tablet contains
Calcium ascorbate dihydrate | 726.0mg |
Sodium ascorbate | 452.0mg |
Glutathione | 10.0mg |
Rutoside | 25.0mg |
Hesperidin | 25.0mg |
Alpha lipoic acid | 20.0mg |
Selenomethionine | 38.0mcg |
equiv. Selenium | 15.0mcg |
Nicotinamide | 5.0mg |
Pyridoxal 5-phosphate monohydrate | 2.19mg |
equiv. Pyridoxine | 1.5mg |
Palm tocotrienols complex (EVNolMax™) | 2.0mg |
Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.<br> Clinical research shows that vitamin B6 can decrease systolic blood pressure in hypertensive patients (30859,82959,83093).
30859
Hatzitolios, A., Iliadis, F., Katsiki, N., and Baltatzi, M. Is the anti-hypertensive effect of dietary supplements via aldehydes reduction evidence based? A systematic review. Clin Exp.Hypertens. 2008;30(7):628-639.
82959
Vasdev, S., Ford, C. A., Parai, S., Longerich, L., and Gadag, V. Dietary vitamin B6 supplementation attenuates hypertension in spontaneously hypertensive rats. Mol.Cell Biochem. 1999;200(1-2):155-162.
83093
Lal, K. J., Dakshinamurti, K., and Thliveris, J. The effect of vitamin B6 on the systolic blood pressure of rats in various animal models of hypertension. J Hypertens. 1996;14(3):355-363.
High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.<br> Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6 (3046,10801).
High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.<br> Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6 (3046,10801).
Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.<br> Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect (8892,8893).
Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.<br> Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people (3046).
Theoretically, niacinamide may have additive effects when used with anticoagulant or antiplatelet drugs, especially in patients on hemodialysis.<br> Several cases of thrombocytopenia have been reported for hemodialysis patients treated with niacinamide 1 gram daily. Hemodialysis patients receiving niacinamide had almost a three-fold higher risk of developing thrombocytopenia when compared with those receiving placebo (25563,98940).
25563
Rottembourg JB, Launay-Vacher V, Massard J. Thrombocytopenia induced by nicotinamide in hemodialysis patients. Kidney Int. 2005;68(6):2911-2.
98940
Zhang Y, Ma T, Zhang P. Efficacy and safety of nicotinamide on phosphorus metabolism in hemodialysis patients: A systematic review and meta-analysis. Medicine (Baltimore). 2018;97(41):e12731.
Niacinamide might increase the levels and adverse effects of carbamazepine.<br> Plasma levels of carbamazepine were increased in two children given high-dose niacinamide, 60-80 mg/kg/day. This might be due to inhibition of the cytochrome P450 enzymes involved in carbamazepine metabolism (14506). There is not enough data to determine the clinical significance of this interaction.
Niacinamide might increase the levels and adverse effects of primidone.<br> Case reports in children suggest niacinamide 60-100 mg/kg/day reduces hepatic metabolism of primidone to phenobarbital, and reduces the overall clearance rate of primidone (14506); however, there is not enough data to determine the clinical significance of this potential interaction.
Theoretically, selenium might prolong the sedating effects of barbiturates.<br> Laboratory research suggests that selenium can inhibit the hepatic metabolism of barbiturates (14601,14602). Selenium seems to prolong the sedative effect of pentobarbital in animal models (14601).
14601
Debski B, Milner JA. Dietary selenium supplementation prolongs pentobarbital induced hypnosis. J Nutr Biochem 2004;15:548-53.
14602
Ishikawa M, Sasaki M, Koiwai K, et al. Inhibition of hepatic mixed-function oxidase enzymes in mice by acute and chronic treatment with selenium. J Pharmacobiodyn 1992;15:377-85.
Selenium may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.<br> Clinical research suggests that taking selenium 10 mcg/kg/day can increase bleeding times by increasing prostacyclin production, which inhibits platelet activity (14540). Other clinical research suggests that taking selenium 75 mcg daily, in combination with ascorbic acid 600 mg, alpha-tocopherol 300 mg, and beta-carotene 27 mg, reduces platelet aggregation (74406).
14540
Schiavon R, Freeman GE, Guidi GC, et al. Selenium enhances prostacyclin production by cultured endothelial cells: possible explanation for increased bleeding times in volunteers taking selenium as a dietary supplement. Thromb Res 1984;34:389-96.
74406
Salonen, J. T., Salonen, R., Seppanen, K., Rinta-Kiikka, S., Kuukka, M., Korpela, H., Alfthan, G., Kantola, M., and Schalch, W. Effects of antioxidant supplementation on platelet function: a randomized pair-matched, placebo-controlled, double-blind trial in men with low antioxidant status. Am.J Clin.Nutr. 1991;53(5):1222-1229.
Theoretically, selenium might interfere with warfarin activity. <br> Animal research suggests that selenium can increase warfarin activity. Selenium might interact with warfarin by displacing it from albumin binding sites, reducing its metabolism in the liver, or by decreasing production of vitamin K-dependent clotting factors (14541). Selenium can also prolong bleeding times in humans by increasing prostacyclin production, which inhibits platelet activity (14540).
14540
Schiavon R, Freeman GE, Guidi GC, et al. Selenium enhances prostacyclin production by cultured endothelial cells: possible explanation for increased bleeding times in volunteers taking selenium as a dietary supplement. Thromb Res 1984;34:389-96.
14541
Davila JC, Edds GT, Osuna O, Simpson CF. Modification of the effects of aflatoxin B1 and warfarin in young pigs given selenium. Am J Vet Res 1983;44:1877-83.
Theoretically, selenium supplementation may reduce the effectiveness of immunosuppressant therapy. <br> In vitro research and preliminary clinical evidence suggests that selenium may stimulate the immune system (74483,74445).
74445
Peretz, A., Neve, J., Desmedt, J., Duchateau, J., Dramaix, M., and Famaey, J. P. Lymphocyte response is enhanced by supplementation of elderly subjects with selenium-enriched yeast. Am.J Clin.Nutr. 1991;53(5):1323-1328.
74483
Kiremidjian-Schumacher, L., Roy, M., Wishe, H. I., Cohen, M. W., and Stotzky, G. Supplementation with selenium and human immune cell functions. II. Effect on cytotoxic lymphocytes and natural killer cells. Biol.Trace Elem.Res. 1994;41(1-2):115-127.
Contraceptive drugs might increase levels of selenium, although the clinical significance of this effect is unclear.<br> Some research suggests that oral contraceptives increase serum selenium levels in women taking oral contraceptives; however, other research shows no change in selenium levels (14544,14545,14546,101343). It is suggested that an increase could be due to increased carrier proteins, indicating a redistribution of selenium rather than a change in total body selenium (14545).
14544
Heese HD, Lawrence MA, Dempster WS, Pocock F. Reference concentrations of serum selenium and manganese in healthy nulliparas. S Afr Med J 1988;73:163-5.
14545
Lloyd B, Lloyd RS, Clayton BE. Effect of smoking, alcohol and other factors on the selenium status of a healthy population. J Epidemiol Commun Health 1983;37:213-7.
14546
Capel ID, Jenner M, Williams DC, et al. The effect of prolonged oral contraceptive steroid use on erythrocyte glutathione peroxidase activity. J Steroid Biochem 1981;14:729-32.
101343
Fallah S, Sani FV, Firoozrai M. Effect of contraceptive pill on the selenium and zinc status of healthy subjects. Contraception. 2009;80(1):40-3.
Selenium might reduce the beneficial effects of niacin on high-density lipoprotein (HDL) levels. <br> A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease (7388,11537). It is not known whether this adverse effect is due to a single antioxidant such as selenium, or to the combination. It also is not known whether it will occur in other patient populations.
7388
Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93.
11537
Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6.
Theoretically, alpha-lipoic acid might decrease the effects of thyroid hormone drugs.<br> Animal research suggests that co-administration of thyroxine with alpha-lipoic acid reduces conversion into the active T3 form (8946).
Theoretically, the antioxidant effects of alpha-lipoic acid might alter the effectiveness of antitumor antibiotics.<br> The use of antioxidants like alpha-lipoic acid during chemotherapy is controversial. There are concerns that antioxidants could reduce the activity of antitumor antibiotic drugs, which work by generating free radicals (391). However, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that might interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effect, if any, antioxidants such as alpha-lipoic acid have on chemotherapy involving antitumor antibiotics. Advise patients to consult their oncologist before using alpha-lipoic acid.
391
Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
14012
Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S.
14013
Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S.
Theoretically, alpha-lipoic acid may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.<br> In vitro, alpha-lipoic acid inhibits platelet aggregation (98682).
Theoretically, the antioxidant effects of alpha-lipoic acid might alter the effectiveness of alkylating agents. <br> The use of antioxidants like alpha-lipoic acid during chemotherapy is controversial. There are concerns that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals (391). However, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that might interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effect, if any, antioxidants such as alpha-lipoic acid have on chemotherapy. Advise patients to consult their oncologist before using alpha-lipoic acid.
391
Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
14012
Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S.
14013
Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S.
Theoretically, taking alpha-lipoic acid with antidiabetes drugs might increase the risk of hypoglycemia.<br> Although some small clinical studies have suggested that alpha-lipoic acid can lower blood glucose levels (3545,3874,3875,3876,20490,20493,104650), larger clinical studies in patients with diabetes have shown no effect (20494,20495,20496,20498,90443,90445,103326). Additionally, co-administration of single doses of alpha-lipoic acid and glyburide or acarbose did not cause detectable drug interactions in healthy volunteers (3870).
3545
Konrad T, Vicini P, Kusterer K, et al. Alpha-lipoic acid treatment decreases serum lactate and pyruvate concentrations and improves glucose effectiveness in lean and obese patients with Type 2 diabetes. Diabetes Care 1999;22:280-7.
3870
Gleiter CH, Schreeb KH, Freudenthaler S, et al. Lack of interaction between thioctic acid, glibenclamide and acarbose. Br J Clin Pharmacol 1999;48:819-25.
3874
Jacob S, Henriksen EJ, Tritschler HJ, et al. Improvement of insulin-stimulated glucose-disposal in type 2 diabetes after repeated parenteral administration of thioctic acid. Exp Clin Endocrinol Diabet 1996;104:284-8.
3875
Jacob S, Henriksen EJ, Schiemann AL, et al. Enhancement of glucose disposal in patients with type 2 diabetes by alpha-lipoic acid. Arzneimittelforschung 1995;45:872-4.
3876
Jacob S, Ruus P, Hermann R, et al. Oral administration of RAC-alpha-lipoic acid modulates insulin sensitivity in patients with type-2 diabetes mellitus: a placebo-controlled, pilot trial. Free Rad Biol Med 1999;27:309-14.
20490
Porasuphatana S., Suddee S., Nartnampong A., Konsil J., Harnwong B., Santaweesuk A. Glycemic and oxidative status of patients with type 2 diabetes mellitus following oral administration of alpha-lipoic acid: a randomized double-blinded placebo-controlled study. Asia Pac J Clin Nutr 2012;21(1):12-21.
20493
Ansar H., Mazloom Z., Kazemi F., Hejazi N. Effect of alpha-lipoic acid on blood glucose, insulin resistance and glutathione peroxidase of type 2 diabetic patients. Saudi Med J 2011;32(6):584-588.
20494
de Oliveira A. M., Rondó P. H., Luzia L. A., D'Abronzo F. H., Illison V. K. The effects of lipoic acid and a-tocopherol supplementation on the lipid profile and insulin sensitivity of patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial. Diabetes Res Clin Pract 2011;92(2):253-260.
20495
Mazloom Z., Ansar H. The Effect of Alpha-Lipoic Acid on Blood Pressure in Type 2 Diabetics. Iranian Journal of Endocrinology and Metabolism 2009;11(3):245-250.
20496
Volchegorskii I. A., Rassokhina L. M., Koliadich M. I., Alekseev M. I. [Comparative study of alpha-lipoic acid and mexidol effects on affective status, cognitive functions and quality of life in diabetes mellitus patients]. Eksp Klin Farmakol 2011;74(11):17-23.
20498
Du X., Edelstein D., Brownlee M. Oral benfotiamine plus alpha-lipoic acid normalises complication-causing pathways in type 1 diabetes. Diabetologia 2008;51(10):1930-1932.
90443
Hegazy SK, Tolba OA, Mostafa TM, Eid MA, El-Afify DR. Alpha-lipoic acid improves subclinical left ventricular dysfunction in asymptomatic patients with type 1 diabetes. Rev Diabet Stud 2013;10(1):58-67.
90445
Huang Z, Wan X, Liu J, et al. Short-term continuous subcutaneous insulin infusion combined with insulin sensitizers rosiglitazone, metformin, or antioxidant a-lipoic acid in patients with newly diagnosed type 2 diabetes mellitus. Diabetes Technol Ther 2013;15(10):859-69.
103326
Ebada MA, Fayed N, Fayed L, et al. Efficacy of alpha-lipoic acid in the management of diabetes mellitus: A systematic review and meta-analysis. Iran J Pharm Res. 2019;18(4):2144-2156.
104650
Derosa G, D'Angelo A, Preti P, Maffioli P. Safety and efficacy of alpha lipoic acid during 4 years of observation: A retrospective, clinical trial in healthy subjects in primary prevention. Drug Des Devel Ther. 2020;14:5367-5374.
Theoretically, hesperidin might inhibit P-glycoprotein-mediated drug efflux and potentially increase levels of drugs that are substrates of P-glycoprotein. <br> In vitro research shows that hesperidin can inhibit P-glycoprotein efflux (54908). This effect has not been reported in humans.
Theoretically, hesperidin may increase the levels and clinical effects of diltiazem.<br> Animal research suggests that hesperidin may enhance the bioavailability of diltiazem, increasing the plasma area under the curve of diltiazem by up to 65.3% (91761). This effect has not been reported in humans.
Theoretically, taking hesperidin with antihypertensive drugs might increase the risk of hypotension. <br> Some clinical and animal research shows that hesperidin can decrease blood pressure (54851,94543,98697,105278). However, other clinical research shows that hesperidin does not affect blood pressure (102315).
54851
Yamamoto, M., Suzuki, A., Jokura, H., Yamamoto, N., and Hase, T. Glucosyl hesperidin prevents endothelial dysfunction and oxidative stress in spontaneously hypertensive rats. Nutrition 2008;24(5):470-476.
94543
Morand C, Dubray C, Milenkovic D, et al. Hesperidin contributes to the vascular protective effects of orange juice: a randomized crossover study in healthy volunteers. Am J Clin Nutr 2011;93(1):73-80.
98697
Homayouni F, Haidari F, Hedayati M, Zakerkish M, Ahmadi K. Blood pressure lowering and anti-inflammatory effects of hesperidin in type 2 diabetes; a randomized double-blind controlled clinical trial. Phytother Res. 2018;32(6):1073-1079.
102315
Mohammadi M, Ramezani-Jolfaie N, Lorzadeh E, Khoshbakht Y, Salehi-Abargouei A. Hesperidin, a major flavonoid in orange juice, might not affect lipid profile and blood pressure: A systematic review and meta-analysis of randomized controlled clinical trials. Phytother Res. 2019 Mar;33(3):534-545.
105278
Valls RM, Pedret A, Calderón-Pérez L, et al. Effects of hesperidin in orange juice on blood and pulse pressures in mildly hypertensive individuals: a randomized controlled trial (Citrus study). Eur J Nutr. 2021;60(3):1277-1288.
Theoretically, hesperidin may decrease the levels and clinical effects of celiprolol.<br> Animal research shows that concomitant use of hesperidin may reduce the plasma area under the curve of celiprolol by up to 75% (91760). This effect has not been reported in humans.
Theoretically, hesperidin might increase the levels and clinical effects of verapamil.<br> Animal research suggests that hesperidin may enhance the bioavailability of verapamil, increasing the plasma area under the curve of verapamil by 96.8% (91762). This effect has not been reported in humans
Theoretically, concomitant use with CNS depressants may cause additive sedative effects. <br> Animal studies show that hesperidin has sedative effects, due to opioid receptor activity (54841) and can increase sedation when used with diazepam (54789). This effect has not been reported in humans.
54789
Fernandez, S. P., Wasowski, C., Paladini, A. C., and Marder, M. Synergistic interaction between hesperidin, a natural flavonoid, and diazepam. Eur.J.Pharmacol. 4-11-2005;512(2-3):189-198.
54841
Loscalzo, L. M., Wasowski, C., Paladini, A. C., and Marder, M. Opioid receptors are involved in the sedative and antinociceptive effects of hesperidin as well as in its potentiation with benzodiazepines. Eur.J.Pharmacol. 2-12-2008;580(3):306-313.
Theoretically, hesperidin may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs. <br> Animal research suggests that hesperetin, a bioflavonoid aglycone derivative of hesperidin, may have antiplatelet activity (54822).
Theoretically, taking rutin with antidiabetes drugs might increase the risk of hypoglycemia.<br> Animal research suggests that rutin has hypoglycemic effects (105299).
Vitamin C might increase blood levels of estrogens. <br> Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products (129,130,11161). It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall (129,11161). When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements (11161). Monitor these patients for estrogen-related side effects.
129
Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
130
Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
11161
Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35.
Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.<br> Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption (10549,10550,10551,21556). In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely (10549). Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.
10549
Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
10550
Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601.
10551
Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7.
21556
Fairweather-Tait S, Hickson K, McGaw B, et al. Orange juice enhances aluminium absorption from antacid preparation. Eur J Clin Nutr. 1994;48(1):71-3.
Vitamin C can modestly reduce indinavir levels. <br> One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown (11300,93578).
93578
Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15.
11300
Slain D, Amsden JR, Khakoo RA, et al. Effect of high-dose vitamin C on the steady-state pharmacokinetics of the protease inhibitor indinavir in healthy volunteers. Pharmacotherapy 2005;25:165-70.
High-dose vitamin C might reduce the levels and effectiveness of warfarin.<br> Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption (11566). There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time (9804,9806). Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant (9805,9806,11566,11567). However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR) (90942). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.
9804
Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671.
9805
Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479.
9806
Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166.
11566
Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7.
11567
Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6.
90942
Sattar A, Willman JE, Kolluri R. Possible warfarin resistance due to interaction with ascorbic acid: case report and literature review. Am J Health Syst Pharm. 2013;70(9):782-6.
Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.<br> The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa (391). In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.
391
Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
14012
Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S.
14013
Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S.
Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.<br> The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin (391). In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.
391
Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
14012
Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S.
14013
Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S.
Vitamin C can increase levothyroxine absorption. <br> Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH (102978).
Theoretically, vitamin C might decrease levels of fluphenazine. <br> In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started (11017). The mechanism is not known, and there is no further data to confirm this interaction.
High-dose vitamin C might slightly prolong the clearance of acetaminophen.<br> A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases (6451). This effect is not likely to be clinically significant.
Acidification of the urine by vitamin C might increase aspirin levels.<br> It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046). However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction is not clinically significant.
3046
Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
10588
Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413.
10589
Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31.
Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.<br> A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease (7388,11537). It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.
7388
Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93.
11537
Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6.
Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.<br> It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046,4531). However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction probably is not clinically significant.
3046
Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
4531
Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
10588
Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413.
10589
Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31.
Acidification of the urine by vitamin C might increase salsalate levels. <br> It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046). However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction probably is not clinically significant.
3046
Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
10588
Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413.
10589
Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31.
Concomitant use of tocotrienols with anticoagulant or antiplatelet agents might increase the risk of bleeding. However, this has not been reported in humans. <br> Taking tocotrienols orally inhibits experimentally-induced platelet aggregation in humans (3237,104429). Theoretically tocotrienols might increase the risk of bleeding if taken with antiplatelet or anticoagulant drugs. However, tocotrienols 400-800 mg daily have been used with aspirin and/or clopidogrel for 1 year with no clear cumulative antiplatelet effects and no reports of bleeding (104429).
3237
Mensink RP, van Houwelingen AC, Kromhout D, Hornstra G. A vitamin E concentrate rich in tocotrienols had no effect on serum lipids, lipoproteins, or platelet function in men with mildly elevated serum lipid concentrations. Am J Clin Nutr 1999;69:213-9.
104429
Slivka A, Rink C, Paoletto D, Sen CK. Platelet function in stroke/transient ischemic attack patients treated with tocotrienol. FASEB J. 2020;34(9):11838-11843.
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Disclaimer: This information on interactions is licensed from the TRC Natural Medicines Database. Neither Bio Concepts nor TRC are providing medical, clinical or other advice and nothing should be interpreted as constituting such advice. Currently this does not check for drug-drug or supplementsupplement interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgement is necessary.
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*Information taken from Natural Medicines Database regarding “Major” contraindications related to active ingredients only and accurate as of October 2021. Please refer to Natural Medicines Database for more information.