[leonth]

Singapore is not really as litigious a society as US, I don't think there is ever a case where the patient sues the doctor because s/he uses an exemption (non-registered) drug. In some cases the patient probably doesn't even know that the drug is not registered.

Importing a drug under exemption is "serious business" and is usually only done by the most senior doctors (or by approval from a committee of senior doctors). They must exhaust all registered options first before moving to exemption drugs, and the pharmacists play a role in ensuring that (another incentive to do that is the paperwork can be rather significant).

Because you need a pharmacist to do this, it usually happens only in larger establishments like hospitals, where pharmacists are readily available and cooperative.