Pet pharmacy company PetMed Express shares dropped Monday after a weak earnings report due to rising competition from smaller vendors.

Shares closed down 11.9 percent at $35.41 per share following a first-quarter earnings report released before the bell, their biggest drop since July 2012.

The Delray Beach, Florida-based company said it had profit of 62 cents per share versus a FactSet consensus estimate of 63 cents. Sales for the first quarter rose to $87.4 million from $79.7 million a year ago.

Spring and summer is usually peak season for animal pharmacy companies as more pet owners shop for tick and flea protection. President and CEO Menderes Akdag said the profit miss resulted from decreasing prices on products and increased advertising to attract new customers.

Despite the decline, Akdag assured investors that sales were still "going strong" and that increased competition has led to the need for advertising and discounts.

"In fiscal 2019, we will look to build on past successes by focusing on sales growth and further improving our customer service levels," said Akdag.