By Sara Sjolin, MarketWatch

LONDON (MarketWatch) -- The U.K.'s FTSE 100 index ended slightly higher after a wobbly session on Thursday, with optimism over a dovish European Central Bank offsetting declines among drug makers.

The FTSE 100 index closed 0.2% higher at 6,551.15, after trading as high as 6,580.21 earlier in the afternoon.

The afternoon optimism came after ECB President Mario Draghi hinted the Governing Council is moving toward full-blown quantitative easing if current measures aren't enough to beef up the sluggish eurozone economy.

The Bank of England offered no surprises, keeping its key lending rate at 0.5%, a record low, and the size of its bond portfolio at 375 billion pounds ($599 billion).

Adding pressure in London, shares of AstraZenaca PLC dropped 0.6%, after the drug maker reported a sharp decline in third-quarter profit. GlaxoSmithKline PLC (GSK) lost 0.3%.

RSA Insurance Group PLC lost 5% after the company posted a decline in net written premiums.

On a more upbeat note, shares of Randgold Resources Ltd. jumped 8.2% after the gold producer reported a rise in third-quarter profit, as higher output offset lower gold prices.

In U.K. data news, the Office for National Statistics said production rose 1.5% in September, year-over-year, a tad lower than consensus forecasts, according to FactSet.

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