Nearly everything looked great with AbbVie's (ABBV 3.10%) first-quarter results. The big drugmaker's revenue jumped 8.4% year over year, thanks largely to spectacular growth from autoimmune disease drugs Skyrizi and Rinvoq. AbbVie beat Wall Street's top- and bottom-line estimates. The company also raised its full-year earnings guidance.

However, two dark clouds loom over AbbVie that those Q1 numbers don't reflect. Should investors be worried about this healthcare Dividend King?

Tariff trouble could be ahead

None of the Trump administration's tariffs have afected AbbVie so far. That's because the across-the-board tariffs exempted pharmaceuticals. Don't count on seeing this protection last too much longer, though.

President Trump told attendees at the National Republican Congressional Committee dinner on April 8, "We're going to be announcing very shortly a major tariff on pharmaceuticals." The president believes these tariffs will push drugmakers to manufacture their products in the U.S. instead of in other countries.

Importantly, AbbVie's increased full-year earnings guidance included a disclaimer. The company noted that the guidance "is based on the existing trade environment and does not reflect any trade policy shifts, including pharmaceutical sector tariffs, that could impact AbbVie's business."

The big question is: How much would pharmaceutical tariffs hurt AbbVie? CEO Robert Michael briefly addressed the issue in his prepared remarks during the company's Q1 earnings call, saying that the effects of tariffs should be "in line with our peers." He added that AbbVie has "an extensive manufacturing presence in the United States."

When asked later in the call for more details, Michael said that AbbVie probably wouldn't try to pass any price increases resulting from tariffs on to customers. He indicated that the company "could also look at cost efficiencies and productivity initiatives as a source of mitigation."

A potential "existential threat"

While the steep tariffs have wreaked havoc on the stock market, the White House could be considering another move that would present a much greater issue for AbbVie. Reuters reported last week that the Trump administration is thinking about implementing international reference pricing, which would tie U.S. prescription drug prices to the amounts paid by other major countries.

One of the sources cited by Reuters said that international reference pricing presents an "existential threat to the industry and U.S. biosciences innovation." That view could be too gloomy, but such a change could cause revenue and profits to plunge for AbbVie and other U.S. drugmakers.

Michael acknowledged the issue during the Q1 earnings call. He stated, "We hope the administration contemplates the harm that international reference pricing could have on U.S. healthcare, the U.S. healthcare industry, and future innovation."

Notably, the first Trump administration attempted to implement international reference pricing for Medicare Part B drugs near the end of President Trump's first term. However, a federal court issued a temporary injunction that prevented the change from going into effect. The policy was subsequently abandoned by the incoming Biden administration.

Should investors be worried?

Both of these issues represent real concerns for AbbVie investors, and for shareholders of other major U.S. pharmaceutical companies as well, in my view. However, I don't think investors should be overly worried at this point.

Michael is probably right that any pharmaceutical tariffs would affect AbbVie about the same as they would affect its peers. I suspect AbbVie would move quickly to revamp its supply chain to minimize the negative effects of tariffs. The company's earnings growth could be lower than projected, but I'm not too anxious about this issue.

The possibility that the Trump administration might seek to implement international reference pricing is more worrisome. However, any such attempt could be thwarted by federal courts, as happened during Trump's first term. While the president could try to push Congress to pass legislation that would address judicial objections, the lobbying by the pharmaceutical industry against any bill would be intense.

Perhaps worrying about this issue will be warranted down the road. For now, though, I think AbbVie remains one of the best pharma stocks to buy and hold.