Manic markets might have you wondering what companies might be worth buying. It can pay off to pick up healthcare stocks in a tumbling tape, especially healthcare stocks that are steady eddie's or game-changers, or that market must-have products. These three companies, for example, could have what it takes to weather a market storm and reward investors over the long run.

No. 1: The steady-eddie
Johnson & Johnson (NYSE:JNJ) may be best known for baby powder and Band-Aids, but its also a global giant in medical devices and prescription medicine. Last quarter, sales of consumer goods like Listerine totaled $3.2 billion. That's good, but the company hauled in $6.1 billion from medical devices and another $8.2 billion from pharmaceuticals.

Johnson & Johnson revenue offers enviable exposure across healthcare, and, importantly, the company is also massively profitable. On $17.5 billion in first quarter sales, the company was able to deliver $4.3 billion in net earnings.

Given Johnson & Johnson's products are some of the most widely used on the planet, and tailwinds tied to an increasingly longer-living global population support future demand. Investors looking to own a top-shelf healthcare stock as a core holding ought to consider picking this one up -- especially considering that this company's performance in tough times has been impressive. For example, when the S&P got throttled by 36% during 2008, J&J's shares barely budged, dipping by just 7.7%. Combine the company's proven performance with a 54-year track record of boosting dividends and you have a recipe for success in any type of tape. 


No. 2: The game-changer
Edwards Lifesciences (NYSE:EW) is a much smaller company than Johnson & Johnson, but the company's been one of healthcare's best performers over the past five years because its devices are increasingly transforming how doctors fix the narrowing of a patient's aortic valve.

In the past, patients had to undergo risky open-heart surgery to remove and replace those failing valves, but Edwards Lifesciences' transcatheter aortic valves allows doctors to insert a replacement valve within a patient's existing valve using a less-invasive procedure.

Currently, these transcatheter procedures are done on patients at high risk of open heart surgery, such as those who are elderly and frail. However, recent studies showing that this procedure may be effective in intermediate risk patients could significantly increase Edwards Lifesciences' addressable market.

If so, then the company's sales of products used in these procedures could be about to climb significantly from their current levels. This year, Edwards Lifesciences estimates that revenue from its transcatheter valves will eclipse $1.4 billion, up more than 25% year over year.

Given that Edwards Lifesciences is rewriting patient care in a population that can't delay treatment, picking up shares in this company on any pullback could be a savvy move. 

No. 3: The must-have
Few companies provide investors with long-range sales and profit forecasts, but Celgene Corp (NASDAQ:CELG) is one blue-chip biotech that does. The company thinks that its revenue could surpass $21 billion and that its EPS could eclipse $13 per share in 2020. What makes that guidance so remarkable is that Celgene's sales and EPS are only expected to reach $10.75 billion and $5.60 per share this year.

Driving the company's optimism is a stable filled with medicine targeting life-threatening disease. Specifically, Celgene markets the leading therapy for multiple myeloma, Revlimid, and the widely used pancreatic cancer drug, Abraxane. Revlimid sales are expected to clock in at about $6.7 billion, and Abraxane's sales could reach $1 billion this year. Celgene also markets another billion dollar multiple myeloma drug, Pomalyst, and a fast-growing psoriasis drug, Otezla.

Those drugs have patent protection that lasts into next decade, but they're not the only medicines that could reward investors with growing sales and profit. The company is developing new drugs that include a therapy for ulcerative colitis and multiple sclerosis. Both of those indications are big markets with substantial opportunity.

Celgene is also working with Juno Therapeutics on an entirely new class of cancer drugs known as chimeric antigen receptor T-cell therapies, or CAR-T. CAR-T medicine attempts to supercharge a patient's immune system so that it can better find and destroy cancer cells. Studies are already under way in tough-to-treat indications, such as leukemia, that could conceivably lead to an approval as early as 2017. 

Tying it together
Of course, no one knows what the future holds for the market or these stocks, but investors who like to buy stocks when they drop ought to have these three companies on their watch list. All three of them are proven and profitable, and each has catalysts that could allow them to reward investors in the coming decade.