Effects of Herbal Supplements on Clinical Laboratory Test Results (eBook)

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Amitava Dasgupta, University of Texas Medical School, Houston, USA.

Preface 8
Contents 10
1 Commonly used herbal supplements 14
1.1 Introduction 14
1.2 Regulation of the sale of herbal supplements 14
1.3 Sale of herbal supplements and demographics of use 17
1.4 Commonly used relatively safe herbal supplements 18
1.5 Commonly used toxic herbs 27
1.6 Conclusions 28
2 Abnormal liver function tests due to use of herbal supplements 32
2.1 Introduction 32
2.2 Abnormal liver function tests and herbal supplements 32
3 Kelp and thyroid panel tests 42
3.1 Introduction 42
3.2 Kelp and iodine content 42
3.3 Kelp as a herbal supplement 43
3.4 Case report 44
3.5 Role of iodine in thyroid function 44
3.6 Kelp and abnormal thyroid function 46
3.7 Kelp and arsenic 47
3.8 Dietary iodine intake 47
3.9 Conclusions 48
4 Interferences in digoxin immunoassays by various herbal supplements 50
4.1 Introduction 50
4.2 Herbal supplements that interfere with digoxin immunoassays 50
4.3 Conclusions 54
5 Interaction of St. John’s wort with various drugs 58
5.1 Introduction 58
5.2 Mechanism of interaction between St. John’s wort and Western drugs 58
5.3 Interaction between immunosuppressants and St. John’s wort 61
5.4 Interaction between antiretrovirals and St. John’s wort 62
5.5 Interaction between warfarin and St. John’s wort 63
5.6 Interaction between anticancer drugs and St. John’s wort 63
5.7 Interaction between cardiovascular drugs and St. John’s wort 63
5.8 Interaction between theophylline and St. John’s wort 64
5.9 Interaction between antiepileptic drugs and St. John’s wort 64
5.10 Interaction between other central nervous system (CNS)-acting drugs and St. John’s wort 65
5.11 Interaction between oral contraceptives and St. John’s wort 65
5.12 Interaction between opioids and St. John’s wort 66
5.13 Other clinically signifi cant drug interactions with St. John’s wort 66
5.14 Drug interactions of St. John’s wort: impact on therapeutic drug monitoring 66
5.15 Conclusions 68
6 Herbs to avoid with warfarin therapy 72
6.1 Introduction 72
6.2 Interaction between warfarin and herbal supplements 72
6.3 Herbal supplements that increase warfarin efficacy 72
6.4 Herbal supplements that reduce warfarin efficacy 75
6.5 Fruits, vegetables, vitamins and mineral supplements, and other agents that interact with warfarin 76
6.6 Conclusions 78
7 Interaction of ginseng, ginkgo, garlic and ginger supplements with various drugs 80
7.1 Introduction 80
7.2 Ginseng: efficacy and toxicity 81
7.3 Ginkgo biloba: efficacy and toxicity 81
7.4 Garlic and ginger: efficacy and toxicity 82
7.5 Drug interactions with ginseng 83
7.6 Drug interactions with ginkgo biloba 83
7.7 Drug interactions with garlic 84
7.8 Drug interactions with ginger 84
7.9 Conclusions 85
8 Interactions between fruit juices and drugs: clinical impact 88
8.1 Introduction 88
8.2 Drug interactions with grapefruit juice 88
8.3 Drug classes that interact with grapefruit juice 89
8.4 Drug interactions with orange juice 91
8.5 Drug interactions with other fruit juices 92
8.6 Role of therapeutic drug monitoring in identifying fruit juice-drug interaction 93
8.7 Conclusions 94
9 Heavy metal toxicity due to use of Oriental and Ayurvedic medicines 96
9.1 Introduction 96
9.2 Heavy metal toxicity in man 96
9.3 Percentage of herbal supplements contaminated with heavy metals 97
9.4 Case studies 100
9.5 How herbal supplements become contaminated with heavy metals 101
9.6 Pesticide contamination of herbal supplements 102
9.7 Toxicity associated with misidentifi ed herbal supplements 102
9.8 Contamination of herbal supplements: unintentional versus intentional 103
9.9 Role of the clinical laboratory 104
9.10 Conclusions 105
10 Contamination of herbal supplements with Western drugs 108
10.1 Introduction 108
10.2 Contamination of herbal supplements with analgesics 109
10.3 Contamination of herbal supplements with steroids 109
10.4 Contamination of herbal supplements with oral hypoglycemic agents 110
10.5 Contamination of herbal supplements with drugs that correct erectile dysfunction 110
10.6 Contamination of herbal supplements with benzodiazepines and antidepressants 110
10.7 Contamination of herbal supplements with weight loss products 111
10.8 Contamination of herbal supplements with other drugs 111
10.9 Adulterated herbal supplements and the clinical laboratory 113
10.10 Conclusions 113
11 Toxic and dangerous herbs 116
11.1 Introduction 116
11.2 Herbal supplements that may cause death 116
11.3 Other toxic herbal supplements 121
11.4 Conclusion 124
Appendix 128
Index 132
Color plates 136