**Abstract**

Drug Induced Hematological Disorders (DIHD) are one among the most frequently encountered Adverse Drug Reactions (ADRs) among the patients using the systemic drug therapy. These unwanted and noxious incidents are often unnoticed or even neglected most of the time during the clinical practices. However, they largely affect the compliance of the patients with their therapy and subsequently affecting the therapeutic outcome of the drug regimen. The inception of the concept of Pharmacovigilance has largely enlightened on this neglected issue and raised the concern over several scientific sessions. However, this serious issue remained unaddressed clinically. These noxious conditions frequently provoke the adverse events or precipitate the underlying medical complications affecting the safety of the patients. The wise and vigilant use of certain risky medication capable of inducing such clinical conditions can significantly reduce these incidences. Thus, the utilization of the skills and the expertise knowledge of the clinical pharmacist can play a pivotal role in preventing and minimizing such events.

**Keywords:** blood, drug induced disorders, adverse drug reactions, pharmacovigilance, clinical pharmacist, patient safety

### **1. Introduction**

Drugs are now become part of our day-to-day life. The burden of disease in the ever-rising trend and the medical fraternity is progressing exponentially. The pharmaceutical industries are constantly expanding the spectrum of the pharmaceutical by carrying out the research and discovering the newer drugs or by synthesizing the molecule with the better efficacy. All the newer molecule or the formulations released in the market go through the strict regulatory process of their testing for safety and efficacy in the clinical subjects. However, it is not possible to the study the drugs completely. Thus, none of the drugs available in the markets are completely safe [1].

The molecule goes through the laboratory studies followed by the pre-clinical and clinical studies and the molecule able to demonstrate the sufficient safety along with the promising efficacy only will release in the market. This procedure generally takes the longtime of decade or even two-three decades [2]. Study of any marketed product after their release in the market is known as the post-marketing surveillance. Several of drugs with potentiality to threat the safety of the patients are continuously studied during this phase and the drugs with the established causality relationship with the adverse events are then recalled by the regulatory or the safety agencies. The Indian Pharmacopeial commission is one of the apex bodies to continuously monitor the safety of the drugs and collects the signals of the suspected adverse drug reactions [3].

Drug induced disorders are technically the adverse drug reactions occurred by that drug molecule or by the excipients used in the formulation of the drugs. The drug induces the adverse drug reactions by either pharmacokinetic or by the pharmacodynamic mechanism. Some of the most commonly occurring adverse drug reactions are drug induced liver disorders, drug induced pulmonary disorders, drug induced hematological disorders, drug induced renal disorders or any dermatological manifestations [4, 5]. Whatever may be the reactions, this incident possesses great risk to the patient safety and accounts for several injuries and casualties. These unwanted and noxious events generally remain undiagnosed or under-reported due to the various factors. However, the medical sciences are becoming vigilant toward such bitter event and continuously trying to detect, assess, manage, document, and prevent them [6–8].

Drug-induced hematological disorders (DIHD) are one among the major type of adverse drug reactions (ADRs) due to their severity rather than their incidence rate. The incidence rate of the DIHD is less compared to other ADRs, however, they posses the greater risk of morbidity and mortality. Thus, they are rare phenomenon occurring in the clinical setting. Some of the most frequently occurring DIHDs are Drug induced aplastic anemia, followed by drug induced agranulocytosis, megaloblastic and hemolytic anemia. There are few literatures in the scientific databases even reporting the incidences of drug induced thrombocytopenia. The incidence of these event is rare and the majority of ADRs are occurring after the chronic use of the medications. Thus, these ADRs are difficult to identify during the clinical trials and are best detected during the post-marketing surveillance [9–11].
