Pharmacovigilance
Jamaica
PHARMACOVIGILANCE
Dr. Jacqueline E. Campbell
Pharmacovigilance is the science of collecting, monitoring, researching, assessing, and evaluating of current drug safety information from healthcare providers ,with the aim of early identification of drug safety problems, their frequency , characterization & the prevention of harm to patients.
An important goal of pharmacovigilance is the effective and open communication of safety information.
An adverse drug reaction (ADR) is an unintended response, occurring at doses used in humans (Edwards and Aronson 2000). They are defined as any noxious unintended and undesired effects of a drug that occur at doses used for prevention, diagnosis or treatment ( WHO 1996). These reactions may predict hazards for future administration or warrant prevention or specific treatment, alteration of the dosage regimen or withdrawal. In summary an adverse drug reaction is harm directly caused by the drug at normal doses, during normal use.
ADRs are a common clinical problem as they cause significant morbidity and mortality. (Pillans 2008). They are an important cause of iatrogenic disease ( Pirmohamed et al 1998 ) and can involve any organ system, can present clinically in many different ways and have taken over from syphilis and tuberculosis as the disease mimic (Pirmohamed and Park 2003)
Adverse drug reactions have been regarded as a major public health problem since they represent a significant percentage of admissions to hospital and an economic burden (Camargo et al 2006; Patel et al 2007; Lazarou et al 1998 ; Zhan et al 2005).
The safety of medicines has come into question since a series of recalls of high-profile prescription medicines have occurred (Oberholzer-Gee & Noorein Indamar 2004; Topol 2004). Clinical trials and routine regulatory oversight, as practiced currently, frequently fail to uncover important adverse effects for widely marketed products (Kesselheim and Avorn 2007). Numerous articles and editorials relating to drug safety and regulation, with recommendations to overhaul drug safety monitoring, improve vigilance, ensure greater protection to the health of the public and restore trust, have been published in medical journals (Waller and Evans 2003; Furberg et al 2006 ; Psaty and Burke 2006 )
ADRs are a common clinical problem as they cause significant morbidity and mortality. (Pillans 2008). They are an important cause of iatrogenic disease ( Pirmohamed et al 1998 ) and can involve any organ system, can present clinically in many different ways and have taken over from syphilis and tuberculosis as the disease mimic (Pirmohamed and Park 2003)
Adverse drug reactions have been regarded as a major public health problem since they represent a significant percentage of admissions to hospital and an economic burden (Camargo et al 2006; Patel et al 2007; Lazarou et al 1998 ; Zhan et al 2005).
The safety of medicines has come into question since a series of recalls of high-profile prescription medicines have occurred (Oberholzer-Gee & Noorein Indamar 2004; Topol 2004). Clinical trials and routine regulatory oversight, as practiced currently, frequently fail to uncover important adverse effects for widely marketed products (Kesselheim and Avorn 2007). Numerous articles and editorials relating to drug safety and regulation, with recommendations to overhaul drug safety monitoring, improve vigilance, ensure greater protection to the health of the public and restore trust, have been published in medical journals (Waller and Evans 2003; Furberg et al 2006 ; Psaty and Burke 2006 )
DEFINITIONS OF TERMS
ADVERSE EFFECT
This term encompasses all unwanted effects; it makes no assumptions about mechanisms , evokes no ambiguity and avoids the risk of misclassification ( Edwards & Aronson 2000). The terms “ adverse reaction” and “adverse effect” are interchangeable , except that an adverse effect is noted from the point of view of the drug; an adverse reaction is observed from the viewpoint of the patient.
This term encompasses all unwanted effects; it makes no assumptions about mechanisms , evokes no ambiguity and avoids the risk of misclassification ( Edwards & Aronson 2000). The terms “ adverse reaction” and “adverse effect” are interchangeable , except that an adverse effect is noted from the point of view of the drug; an adverse reaction is observed from the viewpoint of the patient.
ADVERSE EVENT
Any untoward occurrence that may present during treatment with a pharmaceutical product but which is not or not necessarily attributed to it
SIGNAL
Reported information on a possible causal relation between an adverse event and a drug, the relation being previously unknown or incompletely documented
CLASSIFICATION OF ADVERSE DRUG REACTIONS
Rawlin & Thompson (1991) devised a classification scheme which continues to be the most frequently used .
| Types of Reaction | Mnemonic | Features | Examples |
| A: Dose related | Augmented | Common, related to pharmacological action of drug, predictable | Hypotension induced by anti-hypertensives, heamorrhage seen with warfarin |
| B:Non dose related | Bizarre | Uncommon, unpredictable, not related to pharmacological action of the drug | Penicillin hypersensivity, malignant hyperthermia |
| C: Dose & time related | Chronic | Uncommon, related to cumulative dose | HPA axis suppression by corticosteroids, Benzodiazepine dependence |
| D: Time-related | Delayed | Uncommon, usually dose related. Delayed onset | Teratogenesis, Carcinogenesis, Tardive dyskinesia |
| E: Withdrawal | End of use | Uncommon. Occurs soon after drug is stopped. | Opiate withdrawal syndrome |
| F: Unexpected failure of therapy | Failure | Common, dose-related, often caused by interactions with other drugs | Decreased oral contraceptive effectiveness when used with anti-tuberculosis medication |
References.
1. Pillans , Peter I Expert Rev Clin Pharmacol.2008;1(5):695-705
2. WHO International drug monitoring: the role of the hospital. Geneva: WHO. 1996
3. Camargo AL, Cardoso Ferreira MB, Heineck I: Adverse drug reactions: a cohort study in internal medicine units at a university hospital. Eur J Clin Pharmacol 2006, 62:143-149.
4. Patel KJ, Kedia MS, Bajpai D, Mehta SS, Kshirsagar NA, Gogtay NJ: Evaluation of the prevalence and economic burden of adverse drug reactions presenting to the medical emergency department of a tertiary referral centre: a prospective study. BMC Clin Pharmacol 2007, 7:8.
5. Lazarou J, Pomeranz BH, Corey P. Incidence of adverse drug reactions in hospitalized patients: a meta-analysis of prospective studies. JAMA., 279, 1200-1205 (1998)
6. Zhan C, Arispe I, Kelley E et al. Ambulatory care visits for treating adverse drug effects in the United States, 1995-2001. J. Qual. Patient Saf. 31, 372-378 (2005).
7. Oberholzer-Gee F. Merck's recall of rofecoxib: a strategic perspective. N. Engl. J. Med. 351, 2147-2149 (2004).
8. Topol EJ. Failing the public health: rofecoxib, Merck, and the FDA. N. Engl. J. Med. 351, 1709 (2004).
9. Kesselheim AS, Avorn J. The role of litigation in defining drug risks. JAMA 297, 308-311 (2007).
10. Waller PC, Evans SJW. A model for the future conduct of pharmacovigilance. Pharmacoepidemiol. Drug Saf. 12, 17-29 (2003).
11. Furberg CD, Levin AA, Gross PA, Shapiro R, Strom B. The FDA and drug safety. Arch. Intern. Med. 166, 1938-1942 (2006).
12. Psaty BM, Burke SP. Protecting the health of the public - Institute of Medicine recommendations on drug safety. N. Engl. J. Med. 355, 1753-1755 (2006).
2. WHO International drug monitoring: the role of the hospital. Geneva: WHO. 1996
3. Camargo AL, Cardoso Ferreira MB, Heineck I: Adverse drug reactions: a cohort study in internal medicine units at a university hospital. Eur J Clin Pharmacol 2006, 62:143-149.
4. Patel KJ, Kedia MS, Bajpai D, Mehta SS, Kshirsagar NA, Gogtay NJ: Evaluation of the prevalence and economic burden of adverse drug reactions presenting to the medical emergency department of a tertiary referral centre: a prospective study. BMC Clin Pharmacol 2007, 7:8.
5. Lazarou J, Pomeranz BH, Corey P. Incidence of adverse drug reactions in hospitalized patients: a meta-analysis of prospective studies. JAMA., 279, 1200-1205 (1998)
6. Zhan C, Arispe I, Kelley E et al. Ambulatory care visits for treating adverse drug effects in the United States, 1995-2001. J. Qual. Patient Saf. 31, 372-378 (2005).
7. Oberholzer-Gee F. Merck's recall of rofecoxib: a strategic perspective. N. Engl. J. Med. 351, 2147-2149 (2004).
8. Topol EJ. Failing the public health: rofecoxib, Merck, and the FDA. N. Engl. J. Med. 351, 1709 (2004).
9. Kesselheim AS, Avorn J. The role of litigation in defining drug risks. JAMA 297, 308-311 (2007).
10. Waller PC, Evans SJW. A model for the future conduct of pharmacovigilance. Pharmacoepidemiol. Drug Saf. 12, 17-29 (2003).
11. Furberg CD, Levin AA, Gross PA, Shapiro R, Strom B. The FDA and drug safety. Arch. Intern. Med. 166, 1938-1942 (2006).
12. Psaty BM, Burke SP. Protecting the health of the public - Institute of Medicine recommendations on drug safety. N. Engl. J. Med. 355, 1753-1755 (2006).
13. Edwards IR, Aronson JK. Adverse drug reactions :definitions ,diagnosis, and management . Lancet 356:1255-59 (2000)
14. Rawlins M, Thompson W. Mechanisms of adverse drug reactions. In: Davies D, ed. Textbook of adverse drug reactions. New York: Oxford University Press 1991:18-45.
15. deShazo R, Kemp S. Allergic reactions to drugs and biologic agents. JAMA 1997; 278:1895-1906
16. Pirmohamed M, Breckenridge AM, Kitteringham NR, Park BK. Adverse drug reactions. BMJ 316, 1295-1298 (1998).
17. Pirmohamed M, Park BK. Adverse drug reactions: back to the future. Br. J. Clin. Pharmacol. 55, 486-492 (2003).
15. deShazo R, Kemp S. Allergic reactions to drugs and biologic agents. JAMA 1997; 278:1895-1906
16. Pirmohamed M, Breckenridge AM, Kitteringham NR, Park BK. Adverse drug reactions. BMJ 316, 1295-1298 (1998).
17. Pirmohamed M, Park BK. Adverse drug reactions: back to the future. Br. J. Clin. Pharmacol. 55, 486-492 (2003).
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