Adverse Drug reaction


An adverse drug reaction is one, which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease or for the modification of physiological functions.

All drugs even if taken in an appropriate dose may cause severe or fatal reactions. Such reactions may neither be predicted nor avoided. Most of the adverse drug reactions are rarely or not likely to be identified in pre-marketing clinical experience of new drugs, therefore the prescriber has to take particular care when prescribing a new drug circulating in the market and be vigilant for unexpected effects.

Post-marketing surveillance is important because pre-marketing safety data is inevitably incomplete and animal tests are insufficient in predicting human safety. Furthermore, only a small number of patients with well-defined illness are studied during pre-marketing clinical trials.

Adverse Drug Reactions Monitoring

Adverse Drug Reactions (ADRs) monitoring is a systematic reporting and evaluation of certain or all adverse reactions to drugs including herbal drugs and vaccines. It provides for systematic inferences on likely chains of causation linking drugs and adverse reaction within a population. It includes the experimental drugs. The science of detection, assessment and prevention of Adverse Drug Reactions is known as Pharmacovigilance.

The objectives of monitoring ADRs are:

  1. To detect the adverse drug reactions as early as possible, especially serious, unknown and infrequent reactions.
  2. To establish the frequency and incidence of the adverse reactions both the well recognized and newly discovered reactions.
  3. To identify all factors that may induce and /or influence the development of adverse drug reactions (e.g. racial factors, drug interactions, irrational drug use, etc) or affect the severity or incidence.
  4. To analyse and disseminate information needed in drug prescribing and regulation.

The National ADR monitoring centre

The National Centre for ADRs monitoring is under the Tanzania Medicines and Medical Devices Authority (TMDA), with offices near EPI-Mabibo, Dar es Salaam. The Centre collects and evaluates ADR reports and feedbacks its findings to the healthcare professionals and the general public. Reported information is also communicated to the World Health Organisation (WHO).

Zonal Drug Information Centres

Four Zonal Drug information Centres located at Muhimbli National Hospital (in Dar es salaam), Bugando Medical Centre (in Mwanza), Kilimanjaro Christian Medical Centre and Mbeya Consultant Hospital are responsible with co-ordinating the collection of ADR reports at respective hospitals and Zones.

What to report

All suspected adverse reactions should be reported whether known or unknown, serious or not, including minor ones. Reports on the new drugs are of great interest because they make easier to monitor the performance of these drugs in the country for any suspected adverse drug reactions.

Who should report

All health care providers including specialists, doctors, dentists, pharmacists and nurses can report ADRs. All affected consumers are encouraged to report ADRs directly to their healthcare professionals and zonal Drug Information centers. The reports should be sent to the Director General, TMDA, P.O. Box 1253, Dodoma, fax +255 22 2450793 email . Adverse drug reaction forms may be obtained from TMDA headquarters, Zonal Drug Information Centres, offices of Regional Medical Officers or Regional Pharmacists and healthcare facilities.

How to report

Suspected adverse reactions for drugs marketed in Tanzania should be reported using a standardised form which is postage pre-paid and self adhesive. It contains the following elements

1. Patient information including Patient identifier, Age/Date of birth, Sex, Weight and relevant medical history.

2. Description of the adverse reaction including date of onset.

3. Suspected drug(s): name (including brand name, if known), dosage, route, start and stop dates, and reasons for use.

4. Treatment given for the reaction(s).

5. Other relevant history, including pre-existing medical conditions

6. Outcome of reactions

7. Name, date, signature and address of the reporter.

All sections of the form should be dully filled prior submission. A separated form should be used for each patient.

For further information contact TMDA

Click here to get guidelines for Monitoring and reporting Adverse Drugs Reactions (ADRs)

Adverse Reaction Reporting Tool