When a specific pharmaceutical company develops and patents a new drug, they are allowed exclusive rights to sell that drug for a period of time. When the patent expires other companies can then market their own products that use that drug. Since the generic companies don’t have the research and development costs their costs and selling price is of their product is often lower.
The recognised ingredient for most spot on flea treatments is fipronil which is safe for use in dogs and cats and is effective against fleas and ticks with rapid action. Fipronil recently became available for generic use. The original patent holder, Merial, produced an excellent flea product ‘Frontline’
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