* Q3 adj EBITDA 2.2 bln eur, slightly below consensus
* Adj EBITDA at consumer health down 16.5 pct
* Still expects to close Monsanto deal in early 2018
* Shares drop 2.4 percent pre-market (Recasts, adds details on consumer health unit)
FRANKFURT, Oct 26 (Reuters) - Operating earnings at Germany's Bayer, which is buying U.S. seeds company Monsanto, edged 4 percent higher as weaker-than-expected consumer healthcare revenues tempered gains in prescription drug sales.
Bayer's adjusted earnings before interest, taxes, depreciation and amortisation (EBITDA) for the third quarter came in at 2.20 billion euros ($2.60 billion), slightly higher than the average forecast by analysts of 2.12 billion euros, helped by continued growth in prescriptions for anti-clotting drug Xarelto.
Adjusted EBITDA at the consumer health unit, owner of brands such as sunscreen Coppertone and allergy remedy Claritin, fell a weaker-than-expected 16.5 percent to 274 million euros.
Bayer, struggling with price pressure from large U.S. drugstore chains and from consumers switching to cheaper rivals, said the U.S. market environment remained challenging.
Bayer said it still expected 2017 EBITDA before special items to come in slightly above last year's level, now excluding plastics maker Covestro, in which it holds a minority stake after selling blocks of shares on the open market.
Bayer, which is seeking antitrust approval for the $66 billion Monsanto deal, reiterated it expected to wrap up the transaction in early 2018.
European regulators on Oct. 5 stopped the clock in the approval process, pushing back the Jan. 22, 2018 deadline to account for extra time that the companies need to garner information requested by the watchdog.
($1 = 0.8453 euros) (Reporting by Ludwig Burger; Editing by Maria Sheahan)