Shares of Adamis Pharmaceuticals Corp. /zigman2/quotes/205166351/composite ADMP -0.55% soared 20.4% on massive volume toward an eight-month high in premarket trading Monday, after the biopharmaceutical company said Zimhi, it's high-dose naloxone injection for the treatment for opioid overdose, has been approved by the Food and Drug Administration. Trading volume spiked to 32.8 million shares, enough to make the stock the most actively traded ahead of the open, and compared with the full-day average of about 2.0 million shares. "We are very excited by this approval and are working with our commercial partner, US WorldMeds, to make this much-needed, lifesaving product readily available to the market," said Adamis Chief Executive Dennis Carlo. "Zimhi provides the highest systemic levels of naloxone compared to any of the nasal or intramuscular products currently available." The stock has soared 132.9% year to date through Friday, while the iShares Biotechnology ETF /zigman2/quotes/206189322/composite IBB +0.98% has tacked on 3.7% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -2.27% has gained 19.0%.