Small Animal Clinical Pharmacology - CYF MEDICAL DISTRIBUTION

CHAPTER 3 ADVERSE DRUG REACTIONS
Pseudoallergic drug reactions
Drug reactions may occur that resemble drug allergies
but do not have an immunological basis. These reactions
are often termed anaphylactoid reactions and do
not require prior exposure to the drug. They occur most
frequently when a drug is given rapidly intravenously.
Anaphylactoid reactions may be due to nonspecific
release of mediators of hypersensitivity or can be due to
the direct effects of the drug on tissues.
Acute cardiovascular collapse can be induced by
intravenous administration of chloramphenicol, aminoglycosides,
tetracyclines and propylene glycol. Intravenous
precipitation of water-insoluble drugs can also
cause acute collapse. Direct release of hypersensitivity
mediators can occur particularly with administration of
iodinated contrast media, some intravenous anesthetics
and opiates (e.g. morphine), polymyxin and thiamine.
Administration of drugs in hypotonic solutions or some
organic vehicles can cause erythrocyte lysis leading to
acute hemolytic reactions which are not immunologically
mediated. Nonimmunologically mediated drug
fevers have also been reported, most frequently with
penicillins and cephalosporins in dogs and tetracyclines
in cats. In humans, aspirin and other nonsteroidal
anti-inflammatory drugs can induce anaphylactoid
reactions through interference with arachidonic acid
metabolism.
REPORTING SUSPECTED ADVERSE
DRUG REACTIONS
When faced with a suspected adverse drug reaction, the
primary responsibility of the clinician is management of
the patient’s clinical situation. However, another important
responsibility is to allow the collective experience
with the implicated veterinary medicine to be evaluated.
Veterinary clinicians should ensure that all suspected
adverse drug reactions are reported to both the manufacturer
of the suspected product and the local regulatory
agency. It is only when reporting frequencies are
high that valid assessments of the roles of suspected
drugs in adverse events can be determined, risk factors
identified, the veterinary profession alerted and appropriate
remedial actions implemented.
Information required
While each country and regulatory agency may have a
unique reporting form (which should be obtained, completed
and returned to both the manufacturer and the
responsible agency if possible) the following details are
commonly requested.
1. Reporting veterinarian’s name, address and
telephone number
2. Owner’s name or case identity
3. Suspected product details
• Full name of product
• Batch number
• Expiry date
• Manufacturer
4. Animal details
• Species
• Breed
• Age
• Sex
• Weight
• Concurrent clinical problems
5. Treatment details
• Reason for treatment/diagnosis
• Administered by whom
• Dose regimen (route, dose rate, frequency and
duration)
• Date(s) and time(s) of treatment
• Number treated
6. Reaction details
• Time between treatment and onset of reaction
• Description of the reaction, management and
any specific or supportive treatment
• Concurrent treatments
• Possible contributing factors
• Outcome of suspected adverse reaction (number
affected, number dead, etc.)
All countries
Although not always mandatory, it is recommended
that all suspected adverse drug reactions should be
reported to the manufacturer(s) of the suspected
product(s) and the local regulatory authority. Contact
details of the manufacturer should be present on the
product label. Details of a number of regulatory authorities
and other groups interested in receipt of spontaneous
reports are set out below.
Australia
For veterinary pharmaceutical, biological and pesticide
products:
APVMA (Australian Pesticides and Veterinary
Medicines Authority), Adverse Experience Reporting
Program, Co-ordinating Veterinarian, PO Box E240,
Kingston ACT 2604, Australia
Tel: 61-2-6210-4806
Fax: 61-2-6210-4813
Website: www.apvma.gov.au; http://www.apvma.gov.
au/qa/aerp.shtml
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