But the drug loses its effectiveness as the disease progresses.

But even the most powerful drugs lost their effectiveness after only an hour or so.

At the same time that the incidence of the disease is rising, the drugs used to control its symptoms have lost their effectiveness.

What if the drug in the hypodermic had lost its strength?

Last year, drugs with $8.2 billion in sales lost protection.

Once a drug loses that protection, generic drugs can quickly eat into its sales.

And over time, the drugs can lose their effectiveness.

But five years later, the drug lost its potency.

Other experts say delays will cost too many lives because the drugs now in use are rapidly losing their effectiveness.

Other shortages have occurred soon after a drug has lost its patent protection.