Prescription Event Monitoring
Dr. Digambar Ambikar
Dr. Digambar Ambikar 1
Definition
• A non interventional cohort technique, which
involves health professionals submitting data
on all clinical events reported by a patient
subsequent to the prescribing of a new drug
• It is a method of studying the safety of new
medications that are used by general
practitioners
Dr. Digambar Ambikar 2
• PEM is a non-interventional, observational
cohort form of pharmacovigilance.
• It is the method of studying the safety of new
medications used by the general practitioner.
• UK based concept
• Individualized form of Pharmacovigilance
• Collaborative effort between Doctor ,
Pharmacist, Patient and Government
Dr. Digambar Ambikar 3
• It was first started in the UK after Practolol
was found to cause the Oculomucocutaneous
syndrome, which could not be detected from
the spontaneous reporting which was already
in place
• In New Zealand, the medicines adverse
reactions committee (MARC) is responsible for
conducting such studies for academic
purposes and the programe is known as the
Intensive medicine monitoring programe
(IMMP).
Dr. Digambar Ambikar 4
• Here patients being prescribed monitored
drugs, which include virtually all New
Chemical Entities are studied.
• The criteria for study drug are:
NCE
New Pharmacological Principle
Predicted wide spread use
Suspected problems
Identified but unquantified risks
Dr. Digambar Ambikar 5
• The Information on the 1st 5000-18000
prescriptions for that drug are then obtained.
• Prescribers are contacted with a questionnaire
to determine subsequent events or clinical
outcomes
• Experiences with the drugs can then be
examined and the incidence of various events
can be estimated
• Comparisons are made between periods
before & after drug use e.g.: The occurrence
of Jaundice with Erythromycin Estolate was
found be such method of study
Dr. Digambar Ambikar 6
• Collection of exposure data begins soon after
the new product is launched
• For each patient in the study, DSRU (Drug
Safety Research Unit) prepares a
computerized longitudinal record in the date
order of drug use
• After prescription to a patient, the DSRU
sends the prescriber a green form of
questionnaire
• Doctorreceives maximum of 4 green forms in
a month
• The study period varies between 1 month to
12 months
Dr. Digambar Ambikar 7
• PEM provides clinically useful information
because it establishes
• Numerator = No. of reports of each event
• Denominator = No. of patients exposed to the
drug
• A definite time frame = The period of
treatment for each patient
• From these data, Incidence densities are
calculated for all events reported during the
treatment with the monitored drug
Dr. Digambar Ambikar 8
• These Incidence Densities/Incidence rates are
ranked in order of frequency
• These ranked lists indicate both the nature &
relative frequency of the events reported
when these drugs are used in general practice
Dr. Digambar Ambikar 9
• Statistical analysis
• The number of events observed during the
treatment period in each individual patient is
recorded and the incidence density for each
event is calculated using the equation:
• IDt = (No of events during treatment period t/
No of patient-months exposed to drug) × 1000
• The incidence density is the measure of the
number of reports of each event per thousand
patient months of exposure to the drug.
Dr. Digambar Ambikar 10
• The process of prescription event monitoring
Dr. Digambar Ambikar 11
• Green form
for PEM study
Dr. Digambar Ambikar 12
• Each green form is reviewed by a medical/
scientific officer monitoring the study, to
identify possible serious ADRs or events
requiring action
• Events are coded and entered in database
Dr. Digambar Ambikar 13
• Modified PEM (M-PEM)
• It uses an observational cohort design for
active surveillance of targeted medicinal
products in England
• M-PEM expands the range of conventional
PEM to facilitate more targeted safety
surveillance .
• The questionnaires are designed to collect
relevant supplementary information in order
to perform more detailed exploration of
specific safety issues.
• The underlying process remains the same as in
conventional PEM
Dr. Digambar Ambikar 14
• Individuals are identified in M-PEM where
they have received an NHS-issued prescription
for the drug of interest.
• These prescriptions will be dispensed to
patients at pharmacies with an NHS contract.
• Pharmacists are required to submit
information on dispensed prescriptions for
medications to a central prescription
processing center within the NHS Business
Services Authority (NHSBSA), formerly the
Prescription Pricing Division (PPD).
Dr. Digambar Ambikar 15
Advantages
1. PEM is non-interventional
2. The method is national in scale and thus
provides real world data
3. Method can detect adverse reactions or
syndromes that none of the reporting
doctors suspected to be due to the drug
4. Method allows close contact between the
research staff and reporting doctors
Dr. Digambar Ambikar 16
5. ADR reporting is more complete by this
method
6. Method is found to be successful in regularly
producing data in 10,000 or more patients
given newly marketed drugs
7. Method identifies patient with ADRs who can
be studied further
8. Allows comparison of safety profile of drugs
belonging to the same therapeutic group
9. Evaluate signals generated by other systems
or databases
Dr. Digambar Ambikar 17
Disadvantages
• The is limited to those from a specific place
only
• The percentage of non respondents (i.e. 30% -
50%) is large & it is difficult to establish
whether these doctor’s patients are different
from those whose doctors responded
• Confounding by indication may also pose a
problem
Dr. Digambar Ambikar 18
• Applications:
• Searching for signal
• Assessment of important AE
• Medically important events
• Reason for stopping the drug
• Ranking of ID and reason for withdrawal
• Automated signal generation
• Long latency adverse reactions
• Comparison with external data
• Outcomes of pregnancy
Dr. Digambar Ambikar 19
