Forty-six billion dollars. That's a big number -- and it's how much was made worldwide from selling diabetes drugs in 2017.

You can count on that total growing over the next several years, as more people are being diagnosed with diabetes at alarming rates. And now, more powerful drugs are being developed. All of this makes the diabetes market an intriguing opportunity for investors.

Market research firm EvaluatePharma recently ranked what it projects will be the top diabetes drugs of 2024. Novo Nordisk's (NVO -1.26%) products dominate the list, although Eli Lilly (LLY -2.10%) and privately held Boehringer Ingelheim placed highly, as well. Here are the top five biggest blockbuster diabetes drugs of the future, according to EvaluatePharma.

Physician with stethoscope writing the word "diabetes" on glass window

Image source: Getty Images.

1. Trulicity

Eli Lilly's Trulicity is projected to be the No. 1 top-selling diabetes drug in the world by 2024. EvaluatePharma thinks the drug will rake in annual sales of $4.6 billion and claim a market share of 7.8%.

Trulicity is a glucagon-like peptide 1 (GLP-1) receptor agonist that helps the body release insulin more effectively. The drug won Food and Drug Administration (FDA) approval in 2014 for treating type 2 diabetes. Sales for Trulicity totaled more than $2 billion last year, with a global market share of 4.4%.

2. Ozempic

Lilly will need to watch out: Novo Nordisk will be breathing down its neck with its own GLP-1 receptor agonist, Ozempic. EvaluatePharma expects Ozempic will make $4.4 billion in sales in 2024, giving Novo's drug a 7.4% market share.

Ozempic also ranked second on another EvaluatePharma list -- the biggest new drug launches of 2018. Novo Nordisk won FDA approval of the drug in treating type 2 diabetes in December 2017, but the full launch of Ozempic began this year. The drug got off to a decent start in Q1, with Novo reporting sales for Ozempic of 69 million Danish krone ($11 million as of May 7, 2018).

3. Jardiance

Boehringer Ingelheim and Lilly co-market Jardiance, which is projected to be the No. 3 best-selling diabetes drug in the world in 2024. The drug is expected to generate sales that year of $3.5 billion and capture 5.9% of the worldwide diabetes drug market.

Jardiance is the most successful of several sodium glucose co-transport (SGLT) 2 inhibitors. It won FDA approval in 2014 for treating type 2 diabetes and secured another approval in 2016 for reducing cardiovascular death in adults with type 2 diabetes. The drug made a little over $1.1 billion last year, with Lilly's portion of sales totaling close to $448 million.

4. Tresiba

Novo Nordisk's second product in the top five is insulin analog Tresiba. EvaluatePharma thinks that Tresiba will generate revenue of nearly $3.4 billion in 2024, with a market share of 5.7%.

Tresiba first won FDA approval in 2015 for use by adults with diabetes and gained an additional approval the following year for treatment of children and adolescents with diabetes. Novo Nordisk notched sales of $1.1 billion for the insulin product in 2017 and claimed a market share of 2.4%.

5. NovoRapid

Only one of the top five best-selling diabetes drugs of the future is expected to experience a decrease in sales. Novo Nordisk's insulin analog NovoRapid likely will see its market share slip from 6.6% in 2017 to 4.3% in 2024. However, the product should still bring in more than $2.5 billion.

After years on the market, key patents for NovoRapid expired in 2014. Novo Nordisk recorded sales of around $3 billion for the product last year. While sales will slip, the decline will be a relatively mild and gradual one. 

Investing opportunities?

With these diabetes drugs on track to rack up billions of dollars in sales in the coming years, are Lilly and Novo Nordisk great stocks to buy right now? Maybe.

If you're looking for income, either of these stocks will probably look pretty good. Lilly's dividend yield stands at 2.6%, while Novo's yield is nearly 2.9%. 

The growth scenario is murkier. Both companies have promising new drugs and pipelines, but both also are weighed down by headwinds for older drugs. My view is that Novo Nordisk could be in better shape over the long run, especially if clinical studies for an oral version of Ozempic are successful.