Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain and altered bowel habits, often accompanied by bloating. IBS is classified by its predominant bowel symptom: constipation (IBS-C), diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Since the exact cause of IBS is unknown, the goal of treatment is symptom control. Some over-the-counter (OTC) products and prescription drugs for IBS are listed in Tables 1-4. The safety of these drugs during pregnancy and lactation is described in Table 5 (online only).

Several currently available antiemetic drugs can prevent vomiting caused by cancer chemotherapy. Anticancer drugs that cause vomiting are listed in the table below.

The FDA recently approved three new drugs for treatment of hyperlipidemia. Ezetimibe (ez et' i mibe; Zetia) is the first in a new class of drugs that inhibit intestinal absorption of cholesterol. Extended-release lovastatin (Altocor) is a new formulation of lovastatin (Mevacor, and others). Extended-release niacin plus (immediate-release) lovastatin (Advicor) is the first fixed-dose combination of lipid-lowering drugs.

The FDA has approved ziconotide (Prialt - Elan) intrathecal infusion for management of severe chronic pain in patients who are intolerant of or refractory to other treatments. Ziconotide is a synthetic neuronal N-type calcium channel blocker. It is intended for use with a programmable implanted microinfusion device, but an external microinfusion device can be used temporarily.

Nabilone, an oral synthetic cannabinoid similar to delta-9-tetrahydrocannabinol (THC), the active ingredient in marijuana, has recently been reintroduced to the US market (Cesamet - Valeant) after a 17-year absence. The previous manufacturer discontinued marketing of the drug for commercial reasons. Nabilone is classified as a Schedule II controlled substance.

Cholinesterase inhibitors are now used routinely in patients with dementia. Rivastigmine transdermal system (Exelon Patch - Novartis), a patch formulation of the cholinesterase inhibitor rivastigmine tartrate, has been approved by the FDA for treatment of mild to moderate dementia associated with Alzheimer's or Parkinson's disease. An oral formulation of rivastigmine tartrate has been available in the US since 2000,2 but gastrointestinal adverse effects possibly related to rapidly rising serum concentrations have limited its use.

The FDA has approved the marketing of desvenlafaxine (Pristiq - Wyeth), the main active metabolite of venlafaxine (Effexor, and others - Wyeth), for treatment of major depressive disorder. Venlafaxine, a norepinephrine and serotonin reuptake inhibitor (SNRI), is available generically as an immediate-release tablet. Venlafaxine extended-release capsules (Effexor XR) are scheduled to go off-patent in 2010.

The FDA has approved the proton-pump inhibitor (PPI) dexlansoprazole (Kapidex - Takeda), a delayed release formulation of the R-enantiomer of lansoprazole (Prevacid - Takeda), for treating and maintaining healing of erosive esophagitis and for treatment of heartburn associated with non-erosive gastroesophageal reflux disease (GERD).

The FDA has approved the marketing of fesoterodine (Toviaz - Pfizer), a muscarinic receptor antagonist, for treatment of overactive bladder. It is the sixth antimuscarinic drug approved for this indication.

The FDA has approved tapentadol hydrochloride (Nucynta - Ortho-McNeil Janssen) for oral treatment of moderate to severe acute pain in patients ≥18 years old. It has been classified as a Schedule II controlled substance