Gadolinium-based contrast agents, which are used mainly for magnetic resonance imaging and angiography, were first introduced partly because of the discovery in the 1990’s that iodine-based contrast agents could cause nephrotoxicity and acute renal failure. Some recent reports have suggested, however, that gadolinium-based agents may also be nephrotoxic.1 One patient who developed acute renal failure after use of gadolinium-based contrast had a renal biopsy that showed acute tubular injury.2Moreover, after exposure to gadolinium-based contrast, some patients with severe renal insufficiency,...

A reader expressed disappointment that our recent listing of “Some Warfarin Drug Interactions”1 did not include acetaminophen. Perhaps it should have. Acetaminophen can increase the anticoagulant effect of warfarin, particularly with continued use, but it does so inconsistently. The mechanism of this interaction has not been established, but may be related to an acetaminophen metabolite inhibiting vitamin K-epoxide reductase, the target for warfarin’s anticoagulant effect.2Patient susceptibility varies, possibly on a genetic basis; occasional use of acetaminophen generally has little or...

The nicotine receptor partial agonist varenicline (Chantix - Pfizer) appears to be the most effective drug available to treat tobacco dependence, but the FDA has added a warning to the package insert about neuropsychiatric symptoms and exacerbations of preexisting psychiatric illness associated with its use. Agitation, hostility, depressed mood, suicidal ideation and suicidal behavior have been reported as postmarketing adverse events in patients who took varenicline and stopped smoking and in those who took the drug and continued to smoke.

Paliperidone palmitate (Invega Sustenna – Ortho-McNeil Janssen) has been approved by the FDA as a once-monthly injection for acute and maintenance treatment of schizophrenia in adults. An extended-release oral formulation (Invega) has been available since 2006.1 Long-acting injections of antipsychotic drugs typically are used to treat patients who cannot adhere to an oral regimen.2,3 Paliperidone is the primary active metabolite of risperidone (Risperdal), which is also available as a long-acting (every 2 weeks) injection. It is unclear whether either risperidone or paliperidone is a better...

The FDA has approved an extended-release formulation of clonidine hydrochloride (Kapvay– Shionogi) for treatment of attention-deficit/hyperactivity disorder (ADHD) in children 6-17 years old. It is the second alpha₂-adrenergic agonist approved for this indication; guanfacine hydrochloride (Intuniv) was the first, but only clonidine is approved for use with stimulants.

The FDA has approved fidaxomicin (Dificid – Optimer), a new oral macrolide antibiotic, for treatment of Clostridium difficile-associated diarrhea in patients ≥18 years old. The incidence and severity of C. difficile infection (CDI) have increased in recent years with the emergence of an epidemic hypervirulent strain (NAP1/B1/027), possibly related to widespread use of fluoroquinolones.

Sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra, Staxyn) have become the standard treatment for erectile dysfunction. Head-to-head comparisons of these agents are still lacking, but some differences between them and new recommendations for their dosing (see Table 2) are worth noting.

The FDA has approved a sublingual spray formulation of fentanyl (Subsys – Insys) for management of breakthrough pain in adult cancer patients who are receiving and are tolerant to opioid therapy (taking ≥60 mg/day of oral morphine or the equivalent). Fentanyl is already available in the US for intravenous, intrathecal, epidural, transdermal and transmucosal use.

Palbociclib (Ibrance – Pfizer), an oral cyclin-dependent kinase inhibitor, has been approved by the FDA for use in combination with the aromatase inhibitor letrozole (Femara, and generics) for first-line treatment of postmenopausal women with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer. It is the first cyclin-dependent kinase inhibitor to become available in the US.

The FDA has approved a once-daily, extended-release chewable tablet formulation of methylphenidate (QuilliChew ER – Pfizer) for treatment of attention-deficit/hyperactivity disorder (ADHD). It is the first long-acting chewable formulation of the drug to be marketed in the US. Immediate-release chewable methylphenidate tablets (Methylin, and generics) have been available since 2003.