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Impacts of climate and climate change on medications and human health

Impacts of climate and climate change on medications and human health Objective: To examine impacts of climate and climate change on medications and human health. P.J. Beggs Department of Physical Geography, Division of Environmental and Life Sciences, Macquarie University, New South Wales Methods: Literature review and analysis of MIMS. Results: Changed climate associated with the enhanced Greenhouse Effect (e.g. increased temperature) may lead to medication-related health impacts through deterioration of storage conditions, increased heat stress from medicationinduced heat intolerance, and by influencing pharmacokinetics. Increases in UV radiation from stratospheric ozone depletion may increase the significance of medications that can lead to an increased sensitivity to the damaging effects of UV radiation (i.e. photosensitivity). Conclusions and Implications: Raising awareness of the impacts of climate on medications, and of climate-related sideeffects, among both health care professionals and the public, should modify behaviour and therefore reduce the risks of such adverse impacts. (Aust N Z J Public Health 2000; 24: 630-2) he coming decades are expected to experience significant changes in global climate, including those resulting from enhancement of the Greenhouse Effect and stratospheric ozone depletion. Perhaps the best estimate is for global mean surface air temperature to increase by about 2°C above current, by 2100. However, projections range from an increase of about 1°C to 3.5°C by 2100. Though these increases may seem small and insignificant, it is important to note that: i) the average rate of warming would probably be greater than any seen in the past 10,000 years; ii) regional temperature changes could differ substantially from the global mean value; and iii) a general warming is expected to lead to an increase in the occurrence of extremely hot days and a decrease in extremely cold days.1 The results of a study by Hennessy and Pittock2 can be used to illustrate the potential importance of the latter points. These authors examined extreme temperature events in south-eastern Australia using a range of warming scenarios for the year 2030. Even a low warming scenario of about 0.5°C resulted in at least 25% more days over 35°C in summer and spring, and at least 25% fewer winter days below 0°C. Depletion of stratospheric ozone (from about 1970) has enabled greater amounts of damaging ultraviolet (UV) radiation to penetrate the Earth’s atmosphere to reach the surface. Although significant ozone depletion was first detected during spring over Antarctica, it now occurs year-round and at all latitudes pole-ward of 30° in both hemispheres.3 One estimate has suggested that the increase in UV radiation at the surface of the Earth will peak at about 15% in mid-latitudes.4 Recovery will be slow, with full recovery expected some time after the middle of the 21st Century.4 It is clear that such climate changes will have both direct and indirect impacts on human health. There is a large body of literature relating to the potential health impacts of increases in UV radiation resulting from stratospheric ozone depletion, and a rapidly growing body relating to the potential health impacts from enhancement of the Greenhouse Effect.5 Nevertheless, only scant mention has been made of the interactions between climate and human medications and the impacts on human health that may result from such interactions. The impacts of climate on medications (and human health) can be assigned to one of four groups: i) climate and medication storage; ii) medication-induced heat intolerance; iii) climate and pharmacokinetics; and iv) medication-induced photosensitivity. This paper aims to examine these impacts of climate on medications, as well as the potential impacts of climate change in this important area of public health. Methods A review of the literature was undertaken. This involved a search of a number of Submitted: February 2000 Revision requested: October 2000 Accepted: November 2000 Correspondence to: Dr P Beggs, Department of Physical Geography, Division of Environmental and Life Sciences, .J. Macquarie University, Sydney, NSW 2109. Fax: (02) 9850 8420; e-mail: pbeggs@ocs1.ocs.mq.edu.au AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH 2000 VOL. 24 NO. 6 Brief Report Impacts of climate and climate change on medications and human health abstracting services including Medline (US National Library of Medicine, Ovid Technologies, Inc.), Biological Abstracts (Biological Abstracts, Inc. (BIOSIS)) and Environmental Abstracts (Congressional Information Service, Inc.). The examination also included an analysis of MIMS6 – Australia’s most comprehensive and authoritative pharmaceutical database. For each product, the database includes information on the generic name, composition, description, actions (including pharmacology and pharmacokinetics), the company that produces the medication, uses/indications, contraindications, precautions, adverse reactions, directions for use, presentation and storage. contribute to the release and diffusion of transdermally administered drugs”. Klein-Schwartz and Oderda13 have highlighted a number of physiological changes in the elderly that may influence absorption, distribution, metabolism and excretion. Such changes may make the elderly particularly vulnerable to climate-induced pharmacokinetic changes. This group is of particular significance given that Australia, like many other countries, has an ageing population. The trend towards retirement to warmer climes may also amplify this effect in the elderly. Medication-induced photosensitivity Results Climate and medication storage A range of climate-related storage requirements was found in the MIMS analysis. Many medications should be stored below a certain temperature (very often 25°C or 30°C). Further, some medications should not only be stored below a certain temperature (or within a certain temperature range) but must also not be refrigerated. Medications were also found that have these requirements and have to be kept at a constant temperature. In addition to temperature requirements, some medications require storage in a dry environment. These storage requirements have been determined from laboratory and field studies that have shown both quantitative and qualitative changes in medications stored outside such conditions (e.g. Ballereau et al.7). The influence of geography has also been highlighted by Dietz et al.8 These authors state that, “since the shelf life of a drug depends on the storage conditions it is kept under until use, as much as on the choice of suitable packaging, the shelf life of one and the same medicinal product may vary from one country to another depending on the climate”. Medication-induced heat intolerance Certain medications may predispose individuals to excessive heat strain by altering physiologically or behaviourally thermoregulatory functions.9 Clark and Lipton10 divided medications into those that impair heat loss and those that increase endogenous heat production. Photosensitivity refers to an abnormal cutaneous response involving the interaction between photosensitising substances and UV radiation. Many medications are photosensitising substances. Indeed, a search of the MIMS database for photosensitivity as an adverse reaction resulted in the listing of 174 products. The study by Bjellerup and Ljunggren14 serves as a good example of one examining medication-induced photosensitivity. These authors investigated differences in the phototoxic potency of two tetracyclines (doxycycline and lymecycline). Tetracyclines are often prescribed for young patients, as they are the medications of choice in Chlamydia infections and acne. Although lymecycline showed only a slight and, at most, low significance increase in erythema compared with placebo, doxycycline showed a substantial and highly significant increase in erythema. Gocke15 has recently reviewed the influence of UV radiation on medications used in the control of psychoses, including schizophrenia and mania. It was concluded that UV irradiation of such medications produces reactive free radicals that possess DNAdamaging properties. A number of commonly used antibiotics have also been studied and found to exhibit strong superoxide radical generation in the presence of UV radiation.16 A number of oral antidiabetics and diuretics have also been studied and some have resulted in phototoxic effects after UVA exposure. McMichael et al.5 have discussed photosensitising medications of relevance to the eye. Ocular effects range from cataractogenesis to erythemal reactions. Discussion Climate and pharmacokinetics The area of heat exposure and medications, and, more specifically, the effects of hyperthermia on pharmacokinetics, has been reviewed recently by Vanakoski and Seppälä.11 Heat exposure can influence medication absorption, distribution and elimination. For example, studies of transdermally or subcutaneously absorbed medications indicate that total medication absorption and plasma medication concentrations can substantially increase during heat exposure.11 Heat-induced local vasodilatation and acceleration of skin blood flow appear to be the main mechanisms leading to this change in absorption.12 Vanakoski and Seppälä11 also state that, “changes in the physicochemical properties of transdermal patches, sweating and increased humidity of the skin may 2000 VOL. 24 NO. 6 The implications of greenhouse-induced climate change on the storage and shelf life of many medications are clearly considerable. Even in situations where air-conditioning, refrigeration and freezing facilities exist, adequate storage of medications can often not be ensured. For example, a number of studies have found that many refrigerators used to store vaccines had temperatures outside the recommended range of 2°C to 8°C (e.g. Reimer and Lewis17). There are many situations in which such facilities do not exist, or storage requirements prevent their use, and medications will be exposed to ambient (or close to ambient) climatic conditions. It is in these situations that climate change may have its greatest impact in this respect. Greenhouse-induced climate change is also likely to result in AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH Beggs Brief Report adverse impacts on human health by placing an increased burden on thermoregulatory functions. Extreme events are important in the development of heat stress and heat stroke. Therefore, the predicted increase in such events is expected by many to lead to future increases in heat stress and heat stroke, although one recent Australian study found expected future changes in mortality due to direct climatic effects were minor.18 The elderly are at greatest risk from heat-related illness, and it is this group that previous authors have noted are major medication consumers and therefore at particular risk from climate change and medicationrelated climate impacts.18,19 Others at particular risk include infants, those with pre-existing physical and mental disease and disability, those with lower socio-economic status, and those employed in certain occupations and activities. It should also be noted that although temperature is the most important climatic factor associated with heat-related illness, it is not the only factor. The impacts of extreme heat are exacerbated by low wind speed, high humidity and intense solar radiation.20 Stratospheric ozone depletion may lead to an increase in the occurrence and severity of photosensitivity reactions as a result of extension of the UV spectrum reaching the Earth’s surface and an increase in the intensity of UV radiation. The implications for public health in Australia are clearly considerable given the existing high levels of sun-related disease, such as non-melanocytic skin cancer and malignant melanoma. In response to the potential impacts outlined above, a number of adaptive strategies could be implemented. Development of more thermostable medications would, to some extent, compensate for the increase in temperature expected in the future. Raising awareness of the impacts of climate on medications and of climaterelated side effects, among both health care professionals and the public, should modify behaviour and therefore reduce the risks of such adverse impacts. For example, it is clearly advisable to avoid extensive UV exposure during therapy with photosensitising medications. There is also a need for improved reporting and surveillance of adverse drug reactions. Collections such as the New South Wales Department of Health’s Emergency Department Data or Inpatient Statistics Collections are well placed to fulfil this need. Acknowledgements I thank three anonymous reviewers for their useful comments on a draft of this paper. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian and New Zealand Journal of Public Health Wiley

Impacts of climate and climate change on medications and human health

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Publisher
Wiley
Copyright
Copyright © 2000 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1326-0200
eISSN
1753-6405
DOI
10.1111/j.1467-842X.2000.tb00531.x
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Abstract

Objective: To examine impacts of climate and climate change on medications and human health. P.J. Beggs Department of Physical Geography, Division of Environmental and Life Sciences, Macquarie University, New South Wales Methods: Literature review and analysis of MIMS. Results: Changed climate associated with the enhanced Greenhouse Effect (e.g. increased temperature) may lead to medication-related health impacts through deterioration of storage conditions, increased heat stress from medicationinduced heat intolerance, and by influencing pharmacokinetics. Increases in UV radiation from stratospheric ozone depletion may increase the significance of medications that can lead to an increased sensitivity to the damaging effects of UV radiation (i.e. photosensitivity). Conclusions and Implications: Raising awareness of the impacts of climate on medications, and of climate-related sideeffects, among both health care professionals and the public, should modify behaviour and therefore reduce the risks of such adverse impacts. (Aust N Z J Public Health 2000; 24: 630-2) he coming decades are expected to experience significant changes in global climate, including those resulting from enhancement of the Greenhouse Effect and stratospheric ozone depletion. Perhaps the best estimate is for global mean surface air temperature to increase by about 2°C above current, by 2100. However, projections range from an increase of about 1°C to 3.5°C by 2100. Though these increases may seem small and insignificant, it is important to note that: i) the average rate of warming would probably be greater than any seen in the past 10,000 years; ii) regional temperature changes could differ substantially from the global mean value; and iii) a general warming is expected to lead to an increase in the occurrence of extremely hot days and a decrease in extremely cold days.1 The results of a study by Hennessy and Pittock2 can be used to illustrate the potential importance of the latter points. These authors examined extreme temperature events in south-eastern Australia using a range of warming scenarios for the year 2030. Even a low warming scenario of about 0.5°C resulted in at least 25% more days over 35°C in summer and spring, and at least 25% fewer winter days below 0°C. Depletion of stratospheric ozone (from about 1970) has enabled greater amounts of damaging ultraviolet (UV) radiation to penetrate the Earth’s atmosphere to reach the surface. Although significant ozone depletion was first detected during spring over Antarctica, it now occurs year-round and at all latitudes pole-ward of 30° in both hemispheres.3 One estimate has suggested that the increase in UV radiation at the surface of the Earth will peak at about 15% in mid-latitudes.4 Recovery will be slow, with full recovery expected some time after the middle of the 21st Century.4 It is clear that such climate changes will have both direct and indirect impacts on human health. There is a large body of literature relating to the potential health impacts of increases in UV radiation resulting from stratospheric ozone depletion, and a rapidly growing body relating to the potential health impacts from enhancement of the Greenhouse Effect.5 Nevertheless, only scant mention has been made of the interactions between climate and human medications and the impacts on human health that may result from such interactions. The impacts of climate on medications (and human health) can be assigned to one of four groups: i) climate and medication storage; ii) medication-induced heat intolerance; iii) climate and pharmacokinetics; and iv) medication-induced photosensitivity. This paper aims to examine these impacts of climate on medications, as well as the potential impacts of climate change in this important area of public health. Methods A review of the literature was undertaken. This involved a search of a number of Submitted: February 2000 Revision requested: October 2000 Accepted: November 2000 Correspondence to: Dr P Beggs, Department of Physical Geography, Division of Environmental and Life Sciences, .J. Macquarie University, Sydney, NSW 2109. Fax: (02) 9850 8420; e-mail: pbeggs@ocs1.ocs.mq.edu.au AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH 2000 VOL. 24 NO. 6 Brief Report Impacts of climate and climate change on medications and human health abstracting services including Medline (US National Library of Medicine, Ovid Technologies, Inc.), Biological Abstracts (Biological Abstracts, Inc. (BIOSIS)) and Environmental Abstracts (Congressional Information Service, Inc.). The examination also included an analysis of MIMS6 – Australia’s most comprehensive and authoritative pharmaceutical database. For each product, the database includes information on the generic name, composition, description, actions (including pharmacology and pharmacokinetics), the company that produces the medication, uses/indications, contraindications, precautions, adverse reactions, directions for use, presentation and storage. contribute to the release and diffusion of transdermally administered drugs”. Klein-Schwartz and Oderda13 have highlighted a number of physiological changes in the elderly that may influence absorption, distribution, metabolism and excretion. Such changes may make the elderly particularly vulnerable to climate-induced pharmacokinetic changes. This group is of particular significance given that Australia, like many other countries, has an ageing population. The trend towards retirement to warmer climes may also amplify this effect in the elderly. Medication-induced photosensitivity Results Climate and medication storage A range of climate-related storage requirements was found in the MIMS analysis. Many medications should be stored below a certain temperature (very often 25°C or 30°C). Further, some medications should not only be stored below a certain temperature (or within a certain temperature range) but must also not be refrigerated. Medications were also found that have these requirements and have to be kept at a constant temperature. In addition to temperature requirements, some medications require storage in a dry environment. These storage requirements have been determined from laboratory and field studies that have shown both quantitative and qualitative changes in medications stored outside such conditions (e.g. Ballereau et al.7). The influence of geography has also been highlighted by Dietz et al.8 These authors state that, “since the shelf life of a drug depends on the storage conditions it is kept under until use, as much as on the choice of suitable packaging, the shelf life of one and the same medicinal product may vary from one country to another depending on the climate”. Medication-induced heat intolerance Certain medications may predispose individuals to excessive heat strain by altering physiologically or behaviourally thermoregulatory functions.9 Clark and Lipton10 divided medications into those that impair heat loss and those that increase endogenous heat production. Photosensitivity refers to an abnormal cutaneous response involving the interaction between photosensitising substances and UV radiation. Many medications are photosensitising substances. Indeed, a search of the MIMS database for photosensitivity as an adverse reaction resulted in the listing of 174 products. The study by Bjellerup and Ljunggren14 serves as a good example of one examining medication-induced photosensitivity. These authors investigated differences in the phototoxic potency of two tetracyclines (doxycycline and lymecycline). Tetracyclines are often prescribed for young patients, as they are the medications of choice in Chlamydia infections and acne. Although lymecycline showed only a slight and, at most, low significance increase in erythema compared with placebo, doxycycline showed a substantial and highly significant increase in erythema. Gocke15 has recently reviewed the influence of UV radiation on medications used in the control of psychoses, including schizophrenia and mania. It was concluded that UV irradiation of such medications produces reactive free radicals that possess DNAdamaging properties. A number of commonly used antibiotics have also been studied and found to exhibit strong superoxide radical generation in the presence of UV radiation.16 A number of oral antidiabetics and diuretics have also been studied and some have resulted in phototoxic effects after UVA exposure. McMichael et al.5 have discussed photosensitising medications of relevance to the eye. Ocular effects range from cataractogenesis to erythemal reactions. Discussion Climate and pharmacokinetics The area of heat exposure and medications, and, more specifically, the effects of hyperthermia on pharmacokinetics, has been reviewed recently by Vanakoski and Seppälä.11 Heat exposure can influence medication absorption, distribution and elimination. For example, studies of transdermally or subcutaneously absorbed medications indicate that total medication absorption and plasma medication concentrations can substantially increase during heat exposure.11 Heat-induced local vasodilatation and acceleration of skin blood flow appear to be the main mechanisms leading to this change in absorption.12 Vanakoski and Seppälä11 also state that, “changes in the physicochemical properties of transdermal patches, sweating and increased humidity of the skin may 2000 VOL. 24 NO. 6 The implications of greenhouse-induced climate change on the storage and shelf life of many medications are clearly considerable. Even in situations where air-conditioning, refrigeration and freezing facilities exist, adequate storage of medications can often not be ensured. For example, a number of studies have found that many refrigerators used to store vaccines had temperatures outside the recommended range of 2°C to 8°C (e.g. Reimer and Lewis17). There are many situations in which such facilities do not exist, or storage requirements prevent their use, and medications will be exposed to ambient (or close to ambient) climatic conditions. It is in these situations that climate change may have its greatest impact in this respect. Greenhouse-induced climate change is also likely to result in AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH Beggs Brief Report adverse impacts on human health by placing an increased burden on thermoregulatory functions. Extreme events are important in the development of heat stress and heat stroke. Therefore, the predicted increase in such events is expected by many to lead to future increases in heat stress and heat stroke, although one recent Australian study found expected future changes in mortality due to direct climatic effects were minor.18 The elderly are at greatest risk from heat-related illness, and it is this group that previous authors have noted are major medication consumers and therefore at particular risk from climate change and medicationrelated climate impacts.18,19 Others at particular risk include infants, those with pre-existing physical and mental disease and disability, those with lower socio-economic status, and those employed in certain occupations and activities. It should also be noted that although temperature is the most important climatic factor associated with heat-related illness, it is not the only factor. The impacts of extreme heat are exacerbated by low wind speed, high humidity and intense solar radiation.20 Stratospheric ozone depletion may lead to an increase in the occurrence and severity of photosensitivity reactions as a result of extension of the UV spectrum reaching the Earth’s surface and an increase in the intensity of UV radiation. The implications for public health in Australia are clearly considerable given the existing high levels of sun-related disease, such as non-melanocytic skin cancer and malignant melanoma. In response to the potential impacts outlined above, a number of adaptive strategies could be implemented. Development of more thermostable medications would, to some extent, compensate for the increase in temperature expected in the future. Raising awareness of the impacts of climate on medications and of climaterelated side effects, among both health care professionals and the public, should modify behaviour and therefore reduce the risks of such adverse impacts. For example, it is clearly advisable to avoid extensive UV exposure during therapy with photosensitising medications. There is also a need for improved reporting and surveillance of adverse drug reactions. Collections such as the New South Wales Department of Health’s Emergency Department Data or Inpatient Statistics Collections are well placed to fulfil this need. Acknowledgements I thank three anonymous reviewers for their useful comments on a draft of this paper.

Journal

Australian and New Zealand Journal of Public Health – Wiley

Published: Dec 1, 2000

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