They benefit from the flat fares that the capital's zone system prescribes; off-peak prices from the centre, using a contactless bank card, are £2.80 to London City (pictured left) and £3.10 to Heathrow.
Therefore, the most common practice was to prescribe "off label" drugs.
The drug had to be prescribed off label (that is, not for its original medical use), which health authorities frowned at.
Most drugs used for companion animals, as the pharmaceutical companies refer to pets, are human drugs that veterinarians prescribe off label.
However, being at least three times more potent than finasteride, dutasteride is frequently prescribed "off label" for both baldness and prostate cancer as well.
The drug is already prescribed "off label" for some 11,000 American women with advanced breast cancer, but the latest approval is expected to increase its use among some 43,000 women deemed suitable candidates for treatment.
There is usually less scientific evidence to support nonapproved uses, and a new survey of physicians has found that many might not even know when they are prescribing off label.
However, Breast Cancer Now said that doctors made themselves personally liable if they prescribed off licence, and have heard encountered many examples of GPs and even specialists being reluctant to do so.
The illegal marketing corrupted and contaminated medical practice, encouraging physicians to prescribe off label, eventually leading the FDA to then approve off label prescribing.
The drug can be prescribed off-licence by psychiatrists in exceptional cases.
However, it is rarely prescribed off-label for other conditions, due to its high cost.
