Definition: Drug Incompatibility refers to interactions between two or more substances which lead to changes in chemical, physical, therapeutic properties of the pharmaceutical dosage form.
A drug interaction is a situation in which a substance (usually another drug) affects the activity of a drug when both are administered together. This action can be synergistic (when the drug’s effect is increased) or antagonistic (when the drug’s effect is decreased) or a new effect can be produced that neither produces on its own.
- Types of Drug Incompatibility:
- Therapeutic incompatibility
- Physical incompatibility
- Chemical incompatibility
1. Therapeutic incompatibility
Definition:It is the modification of the therapeutic effect of one drug by the prior concomitant administration of another. (It is also called drug interactions)
2.Physical Incompatibility/ pharmaceutical incompatibilities.
Definition: Interaction between two or more substances which lead to change in color, odor, taste, viscosity and morphology.
Definition: Reaction between two or more substances which lead to change in chemical properties of pharmaceutical dosage form.
These chemical reactions are also known as pharmacological incompatibilities. The reactions occur when two or more drugs are mixed outside the body of the organism for the purpose of joint administration.
POINTS TO BE CONSIDERED TO AVOID THEIR INTERFERENCE DURING VACCINATION ARE:
1.Poor administration of vaccine
Poor distribution of live vaccine administered by the water or spray route may result in chickens being "missed" in parts of the house.
Do not vaccinate the birds during stress period particularly few days before or after the debeaking, transfer shifting and grading. In these conditions negative Immuno-modulation occur which ended with low level of active immunity.
3. Inactivation of live vaccine:
Vaccine contamination must also be prevented as it can cause serious complications. Live vaccines should always be stored and transported at 2-8oC and never exposed to sunrays. The diluents should be chilled before the reconstitution of vaccines. Live vaccines are disease agents which can cause disease under certain circumstances.
4. Health Status of birds:
Immune system of a sick bird is weak and cannot satisfactorily withstand a vaccine. Vaccination of sick bird can precipitate the incidence of disease and it can also lead to other diseases Immunosuppressive disease cause immune-suppression in birds and the birds will not respond properly to the vaccine resulting in vaccine failure
5. Temperature & Ventilation:
Ambient temperature above 30°C affects the immune system of the birds adversely, so vaccinate birds during cooler period of the day only. Ammonia is produced as breakdown of uric acid (an end product of protein metabolism).
Improper ventilation leads to higher concentration of ammonia (NH3) in poultry house due to which there is immune-suppression and failure of vaccination. This ammonia is prevented to accumulate in the poultry house by ensuring proper ventilation.
6. Age, dose and route of vaccine:
Route and dose prescribed by the manufacturer must be followed. Under dosing will not protect the bird adequately. The age of bird at vaccination, proper timing of revaccination affects the level, quality and duration of immunity. Vaccines may be administered:
POOR ANTIGENICITY OF VACCINES:
Live vaccines must be applied at a level at or above the minimum infective dose. After the live virus has been applied the bird serves as a virus production site. The bird is media in which the initial dose of vaccine can multiply to a level which will stimulate a proper immune response. Inactivated vaccines should contain sufficient amount of antigen to stimulate an immune response when applied the bird as there is no multiplication of the virus of bacteria in the bird.
Note: We must not applied the two live vaccines simultaneously especially which is used for the respiratory system protection (there must be intervals of 15 days between 2 applied).
Causes of Vaccine Incompatibility:
- Prescipitation of drugs
- Inactivation of drugs
- Chemical bond changes
- Formation of toxic metabolism
- Anaphylatic reaction in body(allergy) activation of mast cells basophils,IgE Ab,degranulation of mast cells and basophils and release of inflammatory mediators like Histamine,serotinins,bradykinins and prostaglandins.