"We are worried very much for the lady's health situation."
Pyone Moe Ei, the medical assistant, had spent three hours on Friday afternoon at Suu Kyi's house and has requested permission for a return visit on Saturday to renew the intravenous drip, he said.
Authorities arrested Tin Myo Win, Suu Kyi's doctor, on Thursday after he went to the house to carry out a regular medical check-up on the opposition leader.
Official sources said the he had been denied permission to enter the house, but it was not explicitly stated why he had been detained.
On Wednesday, Myanmar authorities arrested a man identified as John Willian Yeattaw, a US national, after he swam across a lake to the off-limits compound where Suu Kyi is under house arrest.
State media said the man confessed to secretly entering the house.
It is thought to be the first time anyone has successfully sneaked into Suu Kyi's compound, or swam across the lake in an attempt to get there
The man reportedly spent two days there before security forces arrested him when he tried to swim away.
Under house arrest, Suu Kyi is allowed only occasional visits from her doctor and lawyer.
The NLD won a landslide victory in elections in 1990 but the military, which has ruled Myanmar since 1962, has never allowed the party to take office.