Johnson & Johnson beat quarterly profit estimates on higher sales at its pharmaceuticals unit even as it faces fierce competition for some of its biggest drugs. 

Sales from the business, which accounts for more than half of the company's total revenue, rose 4.1% and beat estimates.

The division was mainly boosted by demand for Stelara – its treatment for psoriasis and Crohn's disease – as well as cancer drugs Darzalex and Imbruvica.

J&J's medical device unit, its second-largest business, reported a 4.6% fall in sales but beat analysts' average estimate of $6.44 billion. 

The unit has been struggling with slow growth of its spine and hip business, and the drugmaker has been selling off some underperforming businesses. 

Sales of Stelara jumped about 32% in the quarter to $1.41 billion, while revenue from prostate cancer drug Zytiga, which is facing competition from cheaper generics, fell 19.6%. 

Sales of Darzalex, used to treat multiple myeloma, and Imbruvica, which J&J jointly sells with Abbvie, also rose in double digits on a percentage basis. 

Overall sales increased slightly to $20.02 billion, edging past the average estimate of $19.61 billion, according to IBES data from Refinitiv. 

The company's net profit fell 14.2% to $3.75 billion in the first quarter. 

J&J recorded litigation expense of $423m in the first quarter. The company did not record any litigation expenses the same time last year.  

Excluding items, the company said it earned $2.10 per share, beating analysts' estimate of $2.03 per share.

For the full year, the company said it expects adjusted operational sales, which excludes the impact of M&As and a stronger dollar, to rise between 2.5% and 3.5%.

This compares with its previous forecast of a 2-3% rise.