Antipsychotics are far more effective than mood stabilizers in tackling acute manic episodes, researchers found, and Eli Lilly's Zyprexa, Johnson & Johnson's Risperdal and generic haloperidol outperform the rest.
In a study published in the Lancet medical journal on Wednesday, researchers from Britain and Italy ranked antipsychotic drugs according to their effectiveness and said that since current treatment guidelines don't differentiate between the drugs, their findings could offer useful guidance for doctors.
"Strikingly, some antipsychotic drugs were overall significantly more effective than mood stabilizers," the researchers, led by Andrea Cipriani of Verona University and John Geddes of Oxford University, wrote in their study.
"These results have potential clinical implications that should be considered in the development of clinical practice guidelines."
Mania, defined as an "excessively raised mood," affects around 1 percent of the population worldwide, and experts say it tends to alternate with periods of depression. These swings define the diagnosis of bipolar disorder.
Cipriani's team analyzed the results from 68 randomized controlled trials involving more than 16,000 participants from January 1980 to November 2010 to compare the most common drugs used to treat acute mania in adults.
They found that haloperidol, Zyprexa and Risperdal were the most effective antimanic drugs and said they "should be considered as among the best of the available options for the treatment of manic episodes."
Zyprexa has been one of Elli Lilly's top-selling drugs, but is set to lose its valuable marketing exclusivity in the United States in October.
Haloperidol also had the highest number of significant differences in head-to-head comparisons, coming out better than Otsuka Pharmaceutical's Abilify, known generically as aripiprazole;" carbamazepine, sold as Carbatrol by Shire and Tegretol by Novartis; valproate, sold by Abbott Laboratories as Depakine and Sanofi-Aventis as Epilim; Lundbeck's and Merck's asenapine.
It also ranked higher than Pfizer's Neurontin or gabapentin; lamotrigine, sold by GlaxoSmithKline as Lamictal; AstraZeneca's Seroquel or quetiapine; J&J's Topamax or topiramate and several other generic treatments, including lithium, the researchers said.
Risperdal, Zyprexa and Seroquel were least likely to result in patients deciding to stop their treatment and were better than many mood stabilizers, the study found.
In a commentary on the study also published in the Lancet, Michael Berk of Deakin University, Australia, and Gin Malhi at the Royal North Shore Hospital in Sydney said its findings were likely "to attract much interest and have a substantial effect both on clinical practice guidelines and real-world treatment."
But they added that while haloperidol "seems to have won the race for pole position in the treatment of acute mania," management of these episodes is not always the primary treatment aim.
"Instead, the main goals of treatment are attention to long-term mood stability and prophylaxis," they said, suggesting that haloperidol may not always be best in these circumstances.