BENGALURU, Dec 27 (Reuters) - Indian shares ended higher in volatile trading on Monday, helped by IT and pharmacy stocks, while RBL Bank tumbled after its top boss went on medical leave and the central bank appointed an executive to the lender"s board. The NSE Nifty 50 index (.NSEI) ended up 0.49% at 17,086.25 and the benchmark S&P BSE Sensex (.BSESN) closed 0.52% higher at 57,420.24. Earlier in the session, they fell nearly 1% amid concerns over a global surge in Omicron coronavirus variant cases. Shares of RBL Bank (RATB.NS) shed 18.5%, after falling as much as 25% earlier in the session, as the Reserve Bank of India said the private bank was well capitalised and its financial position was satisfactory. read more RBL on Saturday said its board had accepted a request from Vishwavir Ahuja, its managing director and chief executive officer, to proceed on medical leave with immediate effect. read more The banking regulator"s move to send its nominee to the RBL"s board has put the lens on the private lender"s financial strength and asset quality, said Rahul Sharma, head of research, Equity99 Advisors in Mumbai. The Nifty IT services index (.NIFTYIT) added 0.7%, while the pharma index (.NIPHARM) rose 1.62%. Tech Mahindra (TEML.NS) and Cipla Ltd (CIPL.NS) were top gainers on the Nifty 50 index, rising 3.55% and 2.42%, respectively. Asian stocks weakened with crude oil in holiday-thinned trading on Monday, as uncertainty over the economic impact of the Omicron variant weighed on investor sentiment. Meanwhile, India will start administering COVID-19 booster shots as a precautionary measure to healthcare and frontline workers from Jan. 10, as Omicron cases rose across the country. read more Shares of HP Adhesives ended up 20.7% in their market debut against the initial public offering price of 274 rupees.