Phase IV trial is also known as Post Marketing Surveillance Trial. Phase IV trials involve the safety surveillance (pharmacovigilance) and ongoing technical support of a drug after it receives permission to be sold.Last week, the FDA announced that Ultram and Ultracet may increase the risk of suicide. The drug tramadol is marketed as Ultram and is included in Ultracet. Tramadol is not an opioid, however it possesses weak agonist actions at the μ-opioid receptor, releases serotonin, and inhibits the reuptake of norepinephrine. Some clinicians seem to think that tramadol may be associated with abuse, misuse, and even possibly addiction. The data remains unclear about that.
The FDA also announced "Rare Cases of Liver Injury Reported with Use of Xenical, Alli." The weight-loss medication orlistat is found in these prescription and over-the-counter agents. Given that the risk of liver injury is rare, the drug is still going to be available but will have a new warning on it. You'll still have the option of buying Alli at your local drug store.