PHARMACOVIGILANCE AND DRUG INTERACTIONS
Pharmacovigilance is defined as the activities that deal with the detection, assessment, understanding and prevention of adverse effects of medicinal products in consumers, simultaneously undertaking the monitoring of counterfeit products and making sure that patients are well-informed about their medicines
- Adverse Events & Adverse Reactions
The ICH E2A guideline describes Adverse Events as any “untoward medical occurrence” which happens to either a patient or a subject in a clinical investigation when a pharmaceutical product has been given to that person. This encompasses any signs which are unfavourable and unexpected for the patient or subject, including any abnormal laboratory findings. These could be symptoms or a diseases temporally associated with the use of a medicinal product, and do not have to have been previously associated with that product. Neither do they have to have a known causal relationship with the course of treatment.
- Serious Adverse Events (SAEs)
As the names implies, these are “any untoward medical occurrence” that:
- Is fatal
- Is a threat to life
- Results in inpatient hospitalisation
- Prolongs an existing hospital stay
- Results in persistent or significant disability or incapacity
- Results in a congenital anomaly or birth defect
Events that require intervention to prevent the patient or subject experiencing any of the outcomes listed above or otherwise jeopardise the patient are also to be classed as serious, depending on their nature. In some cases expedited reporting will clearly be appropriate. In the EU, suspected transmission of an infectious agent also constitutes a serious adverse event.
- Drug interactions
- Drug interaction is defined as the pharmacological activity of one drug is altered by the concominant use of another drug or by the presence of some other substance.
- The Drug whose Activity is effected by such an Interaction is called as a “Object drug.” • The agent which precipitates such an interaction is refered to as the “Precipitant”.
- Types of drug Interactions 1.Drug-drug interactions. 2.Drug-food interactions. 3.Chemical-drug interactions. 4.Drug-laboratory test interactions. 5.Drug-disease interactions.
- The Net effect of a Drug Interaction is: •Generally quantitative i.e. increased or decreased effect. •Seldom qualitative i.e.rapid or slower effect. •Precipitation of newer or increased adverse effect.
- Drug interactions are thus- • Mostly undesirable • Rarely desirable(beneficial): for eg.,enhancement of activity of penicillins when administered with probenecid.
- Factors contributing to drug interactions: 1.Multiple drug therapy. 2.Multiple prescribers. 3.Multiple pharmacological effects of drug. 4.Multiple diseases/predisposing illness. 5.Poor patient compliance. 6.Advancing age of patient. 7.Drug-related fact
- Mechanisms of drug interactions: The three mechanisms by which an interaction can develop are
- Pharmaceutical interactions. 2.pharmacokinetic interactions. 3.Pharmacodynamic interactions.
- Pharmaceutical interactions: Also called as incompatibility.it is a physicochemical interaction that occous when drugs are mixed in i.v . Infusions causing precipitation or inactivation of active principles . Example:- Ampicillin ,chlorpromazine and barbituates interact with dextran in solutions and are broken down or from chemical compounds.
- Pharmacokinetic Interactions: “These interactions are those in which adme properties of the object drug is altered by the precipitant and hence such interactions are also called as ADME interactions”. •The resultant effect is altered plasma concentration of the object drug. •These are classified as: 1.Absorption interactions 2.Distribution interactions 3.Metabolism interactions 4.Excretion interactions.
- Absorption interactions :Are those where the absorption of the object drug is altered. The net effect of such an interaction is: • Faster or slower drug absorption. • More, or, less complete drug absorption.
- Teacher: Maryam Akin