This week, the ratings of 6 Pharmaceuticals stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Slipping from a C to a D rating, Jazz Pharmaceuticals Plc (JAZZ) takes a hit this week. Jazz Pharmaceuticals Plc is a specialty pharmaceutical company focused on developing and commercializing products to meet medical needs in neurology and psychiatry. For more information, get Portfolio Grader’s complete analysis of JAZZ stock.

Mylan N.V. (MYL) declines this week from a C to a D. Mylan N.V. is a global generic and specialty pharmaceuticals company. The company also gets F’s in earnings momentum. For more information, get Portfolio Grader’s complete analysis of MYL stock.

Akorn, Inc. (AKRX) is having a tough week. The company’s rating falls from a C to a D. Akorn, Inc. engages in the manufacture and marketing of diagnostic and therapeutic ophthalmic pharmaceuticals products, niche hospital drugs, and injectable pharmaceuticals in the United States and internationally. The company also gets F’s in operating margin growth. For more information, get Portfolio Grader’s complete analysis of AKRX stock.

This week, Relypsa, Inc.’s (RLYP) rating worsens to a D from the company’s C rating a week ago. The company also gets F’s in earnings momentum, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of RLYP stock.

Aratana Therapeutics, Inc. (PETX) slips from a C to a D this week. The company also gets F’s in sales growth, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of PETX stock.

Pernix Therapeutics Holdings, Inc. (PTX) earns a F this week, moving down from last week’s grade of D. Pernix Therapeutics Holdings, Inc. manufactures pharmaceuticals. The company also gets F’s in earnings revisions, earnings surprise, earnings momentum, and return on equity. For more information, get Portfolio Grader’s complete analysis of PTX stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.