But Mr Bryant said he believed "all drugs are dangerous" and the long-term side effects of certain drugs, such as cannabis, were only now coming to light.

BBC: Richard Brunstrom acknowledges his is a minority view

In some cases, as with the elderly, pregnant women and children, these older, cheaper drugs may be preferable because they are less likely to have certain side effects.

FORBES: Magazine Article

Wyeth is also developing another medicine to treat menopause symptoms and a new drug for osteoporosis, a treatment for the side effects of morphine, and an improved version of its Prevnar vaccine, which prevents certain bacterial infections in infants and toddlers.

FORBES: Wyeth's Worries

If these certain enzymes cannot break down the medications, the drugs can become toxic and lead to serious and deadly side effects.

FORBES: Caution When Taking Grapefruit Juice with Certain Medications