Introduction
Post marketing surveillance is defined as the process of gathering information about a particular product after its approval for public use. It comprises of case-control studies, adverse event monitoring, randomized trials, marketing surveys, analysis of important statistics and cohort studies. In the United States, drug manufacturers are required to provide evidence to FDA that the drugs they manufacture are efficient and safe. After the premarketing requirements are met, FDA has the capacity to withdraw the drugs from the market once it is discovered that the drug’s approval was made on the basis of unmet manufacturing conditions or false facts. In situations when a drug poses potential threat to the health of its users, its approval is suspended with an immediate effect followed by appropriate actions (Gill 121).
Although it is not possible to provide information on the safety or efficacy of drugs when they are introduced to the market through postmarketing surveillance, various postmarketing surveillance kinds have been cited as crucial ways of monitoring and modifying the use of drugs. The main focus of proposals on postmarketing surveillance has been using prescription drugs safely, though the efficacy and safety considerations have been included as part of the focus. Currently, the interest in monitoring and prescription drug evaluation is on the process of premarketing approval and the duration taken before the drug is approved by FDA. Postmarketing surveillance supposedly has been losing its ground as a policy matter but it should be taken seriously as a policy matter for short-term and long-term aims (FDA 2).
Events Pertaining to Post marketing Drug Surveillance
Drug Approval Process
During the approval process, sponsors of drugs must provide enough tests that confirm whether the drugs are safe for use under the prescribed or suggested conditions, and adequate evidence that the drug will deliver the effect it is supposed to deliver. This requirement led FDA into establishing a premarketing stage of drug testing that is comprised of two parts. The first process is the Investigational New drug (IND) application process while the second one is filing of a new drug application (NDA). IND application gives details on the qualifications of the investigator and the scheduled clinical tests, chemical composition of the drug and the new drug toxicology and pharmacology data (Strom and Velo 53).
The clinical investigations during the IND process are sub-divided into three stages. The first stage is referred to as clinical pharmacology and involves testing the drug on human beings in order to confirm pharmacological effects and dose ranges. The number of subjects during this stage is dependent on the drug, but normally, it ranges between 20 and 80. The second stage is known as clinical investigation and comprises of clinical trials which are controlled to show the relative safety and efficiency of a drug.
Clinical investigation procedures are done on a limited number of patients who are closely monitored. The number is usually between 200 and 300 patients with an equal number representing the control patients. The third stage is known as clinical trials and consists of uncontrolled and controlled trials used in collecting further evidence on the effectiveness of a drug in particular indications and identifying its adverse effects in a more precise manner. In more natural settings, the number of patients observed in stage three ranges from 500 to 3000 patients. In clinics and hospitals, the stage is usually made up of more than two controlled trials. After the testing demanded by IND application is over, a sponsor may file for an NDA.
Addressing Post marketing Drug Surveillance Questions
Because of the varying needs of collecting information on drugs, post-marketing surveillance studies pose certain questions. The first question posed by post marketing surveillance studies is whether there is a relationship between a drug and an outcome. Identifying cause-effect relationships existing between drugs and clinical results is one of the objectives of post marketing studies. However, since causality cannot be determined through empirical science, post marketing surveillance provides evidence for or against causality.
The second question post marketing surveillance on drugs poses is the frequency of drug-induced outcomes. The frequency of occurrence of outcomes is related to the existence of a causal relationship between a drug and an outcome. The third question posed by post marketing drug surveillance is the economic consequences of therapy while the fourth question addressed by post marketing surveillance of drugs is the use of drugs in clinical practice (Liu and Davis 135).
Techniques and Tools of Post marketing Drug Surveillance
The key aim of conducting post marketing surveillance is to gather information about the effects of drugs under customary circumstances of drug use. Initial indicators of the potential effects a drug may have are acquired by carrying out experimental studies on both animals and human beings during the premarketing period. Most of the studies of obtaining information on drug effects employ either case-control or cohort methods (McFadden 121). There are four basic techniques and tools used in identifying the effects of drugs.
Controlled Clinical Trials
Controlled clinical trials match control and treatment groups closely, reduce bias arising from methods such as double-blinding and randomization and monitor the patients directly during the study period. Control clinical methods are regarded as suitable techniques for evaluating the safety and efficacy of drugs although they are expensive and might not be practical in particular circumstances, for example, when the effects of a drug are rare or surface after a long period of the drug use (Prokscha 48).
Spontaneous or Voluntary Reporting
Physicians, hospitals and other health providers may voluntarily report to FDA and pharmaceutical firms on likely serious drug effects. As a result, the disruption of the link between a drug and an identified health condition may be studied in depth through careful reporting and either confirmed or dismissed my thorough techniques. Underreporting is one of the serious shortcomings of this technique. In other situations, there might be an association between a drug and adverse effects or for the suspected association to be unidentified through statistically validated studies (Clinical Therapeutics 35).
Cohort Studies
Cohort studies concentrate on a group of patients that is defined (the cohort) for a certain duration of time. This technique does not involve random assigning of patients to groups, and does not use blinding. This technique is prospective with the patients being observed once they start using the drug. A certain number of patients taking the drug under investigation are gathered then follow up made to determine if adverse reactions take place. A second group which is referred to as the control group with similar medical conditions and not using the drug, and whose members may be under alternative medication, but which is closely matched with the cohort is studied in parallel (ncbi 1). The purpose of the control group is to help in identifying the frequency of occurrence of conditions evident in the group taking the drug whose cause is other than the drug. With this technique, it is possible to monitor the patients directly to ensure they rightly take the drug and observe its effects. The monitoring can also be less controlled in order to follow a larger cohort although this increases the chances of bias.
Case Control Studies
In case-control studies, patients with adverse effects under study (the cases), are identified and compared with a sample (the controls), obtained from the same cohort that produced the cases. A close matching of the controls with the cases is done, except regarding the suspected adverse effects of the drug to determine whether the cause emanates from exposure to the drug (Zhang 254). The medical records of patients who exhibit conditions suspected to be occasioned by certain drugs are reviewed or interviewed regarding the drug use.
The histories of the control groups are also examined to gather information concerning the use of drugs in the whole population. By making a comparison of the percentage of drug users among the cases with the percentage of those who use drugs in the entire population, the relative frequency of adverse effects among users of particular drugs in comparison with non users can be determined. A good number of relevant cases must be identified and reliable exposure histories to drugs acquired (Gad 342).
Conclusion
Post marketing surveillance on drugs is any activity involved in gathering information after the approval of a drug. Post marketing surveillance studies on drugs pose various scientific questions. Although various academic disciplines conduct the studies, majority of the investigations are epidemiological in nature, whether non-experimental such as cohort and case control studies or experimental such as randomized trials. Their designs notwithstanding, post marketing surveillance studies on drugs should be carried out by trained investigators guided by written protocols. It is unacceptable to conduct promotional activities on drugs in the name of post marketing surveillance.
Works Cited
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