AmerisourceBergen Corporation’s ABC third-quarter fiscal 2018 results are scheduled for release on Aug 2, before market opens. While the company’s core Pharmaceutical Distribution unit is likely to drive growth, stiff competition is likely to mar prospects.In the last reported quarter, the company posted adjusted earnings of $1.94 per share beating the Zacks Consensus Estimate by 6% and improving 9.6% year over year. Revenues improved almost 10.5% to $41.03 billion, surpassing the Zacks Consensus Estimate of $40.48 billion.For the quarter to be reported,the Zacks Consensus Estimate for revenues is pegged at $42.96 billion, reflecting year-over-year growth of 11%. The same for earnings is pinned at $1.45, showing year-over-year growth of 1.4%.AmerisourceBergen Corporation Price and EPS Surprise AmerisourceBergen Corporation Price and EPS Surprise | AmerisourceBergen Corporation QuoteLet’s dig deeper to analyze how things are shaping up before the earnings announcements.Pharmaceutical Distribution to be Key DriverThis segment serves healthcare providers in the pharmaceutical supply channel. In the last reported quarter, the segment accounted for 96.3% of the company’s net revenues. Moreover, the segment’s revenues grew 10.4% on a year-over-year basis to $39.5 billion.It is encouraging to note that the Zacks Consensus Estimate for the quarter to be reported stands at $41.3 billion, showing an improvement of 11.5% from the year-ago quarter.Per management, the segment has continued to surpass the company’s expectations for a year now. Strong organic growth rates in the U.S. pharmaceutical market, improving patient access to medical care, improved economic conditions and population demographics should reflect in the results of the quarter to be reported.Moreover, in recent times, MedTech bigwig Walgreens’ 1,900 acquired Rite Aid stores have been integrated into the Pharmaceutical distribution network.Other Factors to ConsiderOther SegmentThis segment consists of AmerisourceBergen Consulting Services (ABCS), World Courier and MWI Veterinary Supply.In the last reported quarter, the segment contributed 3.9% to the company’s net revenues. Notably, revenues in the segment improved 12.6% year over year to $1.6 billion.Furthermore, the Zacks Consensus Estimate for the quarter to be reported is pegged at $1.81 billion, showing a sequential rise of 13.4%.The company eyes the launch of the Fusion platform, which is likely to boost this segment in the quarters ahead.Guidance SolidFor fiscal 2018, AmerisourceBergen expects revenue growth in the range of 8-11% on a year-over-year basis. Notably, the Zacks Consensus Estimate for revenues is currently pegged at $168 billion, up 9.4% year over year.The company expects adjusted earnings per share in the range of $6.45-$6.65. AmerisourceBergen expects adjusted operating expenses to increase in the range of 8-10%, up from the previous range of 6-8%. The Zacks Consensus Estimate for earnings is currently pegged at $6.47 per share, within the range.Thus, AmerisourceBergen is confident about improving its growth trajectory with strong prospects in the World Courier Business. Solid volume growth and expanding operating margins are likely to drive third-quarter results.CompetitionAmerisourceBergen operates in a highly competitive pharmaceutical distribution and related health care services market. The company’s primary competitors include Cardinal Health and McKesson along with national generic distributors and regional distributors. Moreover, additional competition from manufacturers, chain drugstores, specialty distributors and packaging and health care technology companies is a headwind.Other HeadwindsAmerisourceBergen’s PharMEDium lab in Memphis had negatively impacted the company’s sales in the last reported quarter. Currently, remediation efforts are underway at the Memphis facility, where operations have been suspended since December. Per management, contribution from PharMEDium's Memphis facility has been removed from the company’s fiscal 2018 expectations.Moreover, the company’s Lash Consulting business also registered lower-than-expected revenues in the last reported quarter.Earnings WhispersOur model does not conclusively show an earnings beat for AmerisourceBergen in the third quarter. This is because a stock needs to have a positive Earnings ESP and a Zacks Rank #1 (Strong Buy), 2 (Buy) or 3 (Hold) for this to happen. That is not the case here as you will see below.Earnings ESP: AmerisourceBergen has an Earnings ESP of -0.32%. You can uncover the best stocks to buy or sell before they’re reported with our Earnings ESP Filter.Zacks Rank: AmerisourceBergen carries a Zacks Rank #3.Here are a few medical stocks worth considering as they have the right combination of elements to post an earnings beat this quarter.Edwards Lifesciences Corporation EW has an Earnings ESP of +0.59% and a Zacks Rank #3. You can see the complete list of today’s Zacks #1 Rank stocks here.Teleflex Incorporated TFX has an Earnings ESP of +0.34% and a Zacks Rank #3.PerkinElmer, Inc. PKI has an Earnings ESP of +1.03% and a Zacks Rank #3.Will You Make a Fortune on the Shift to Electric Cars?Here's another stock idea to consider. Much like petroleum 150 years ago, lithium power may soon shake the world, creating millionaires and reshaping geo-politics. Soon electric vehicles (EVs) may be cheaper than gas guzzlers. Some are already reaching 265 miles on a single charge.With battery prices plummeting and charging stations set to multiply, one company stands out as the #1 stock to buy according to Zacks research.It's not the one you think.See This Ticker Free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Teleflex Incorporated (TFX): Free Stock Analysis Report PerkinElmer, Inc. (PKI): Free Stock Analysis Report Edwards Lifesciences Corporation (EW): Free Stock Analysis Report AmerisourceBergen Corporation (ABC): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research