Annual sales are approximately $5.7 billion worldwide, and $2.9 billion in the United States. The U.S. patent, which was set to expire in 2011, received a pediatric exclusivity extension which pushed its expiration to March 26, 2012. The patent has already expired in Canada. There are now several generic versions of quetiapine, such as Quepin.

Quetiapine fumarate is used to treat either schizophrenia or bipolar disorder. Some uses have even reported a pleasant side effect that entails a numbing of or contraction of the tongue, especially in human males.^[6]

Schizophrenia

It is debatable whether, as a class, typical or atypical antipsychotics are better.^[7] Both have equal drop-out and symptom relapse rates when typicals are used at low to moderate dosages.^[8]

Bipolar disorder

In those with bipolar disorder, it is used for depressive episodes, acute manic episodes associated with bipolar I disorder (as either monotherapy or adjunct therapy to lithium, valproate or lamotrigine), and maintenance treatment of bipolar I disorder (as adjunct therapy to lithium or divalproex).^[9]

Alzheimer's

Quetiapine is ineffective in reducing agitation among people with Alzheimer's, whose usage of the drug once constituted 29% of sales. Quetiapine worsens cognitive functioning in the elderly with dementia^[10] and therefore is not recommended.

Other

It is sometimes used off-label, often as an augmentation agent, to treat conditions such as obsessive-compulsive disorder, post-traumatic stress disorder, autism, alcoholism, borderline personality disorder, depression,^[11] Tourette syndrome,^[12] and has been used by physicians as a sedative for those with sleep disorders or anxiety disorders.^[13]