A new CDC guideline for prescribing opioids for pain recently became available. Nonopioid drugs for pain were reviewed in a previous issue.

Recent reports of inappropriate use and diversion of OxyContin tablets have prompted Purdue Pharma to include a "Black Box Warning"in the product labeling to call attention to the potential for abuse and to reinforce the FDA-approved indication "...for the management of moderate to severe pain when a continuous, around-the-clock analgesic is needed for an extended period of time..."

Breaking drug tablets in half is a common practice. Since our last article on this subject, some new data have become available.

Testing for drug use has become increasingly common, not only in health care, but also in drug rehabilitation, in the military, at the workplace, after accidents and in the criminal justice system. Performance-enhancing drugs such as anabolic steroids, growth hormone (Genotropin, and others) and erythropoietin (Procrit, Epogen) are not discussed here.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Previously approved by the FDA for treatment of depression, general anxiety disorder, diabetic peripheral neuropathic pain and fibromyalgia, duloxetine (Cymbalta – Lilly) has now also been approved for treatment of chronic musculoskeletal pain.

An oral solution (Vituz – Hawthorne) containing two old drugs, the centrally-acting opioid hydrocodone bitartrate and the first-generation H1-antihistamine chlorpheniramine maleate, has been approved by the FDA for relief of cough and [other] symptoms associated with upper respiratory allergies or a common cold in adults. Several extended-release products containing hydrocodone and chlorpheniramine are available as capsules and suspensions and have been used for years for similar indications. Vituz is classified as a schedule III controlled substance, but the FDA has asked the DEA...

The Drug Enforcement Administration (DEA) has reclassified all hydrocodone combination products as schedule II controlled substances; they were previously classified as schedule III. Hydrocodone alone (Zohydro ER) is already a schedule II controlled substance.

The opioid agonist tramadol is now available in an oral solution (Qdolo – Athena Bioscience) for management of pain severe enough to require an opioid and for which alternative treatment options are inadequate. Tramadol has been available for years in immediate-release tablets and capsules, extended-release capsules (Ultram, and others), and in a fixed-dose combination tablet with acetaminophen (Ultracet, and generics).

The FDA has approved a low-dose formulation of the selective serotonin reuptake inhibitor (SSRI) paroxetine mesylate (Brisdelle – Noven Therapeutics) for treatment of moderate-to-severe vasomotor symptoms associated with menopause. It is the first non-hormonal therapy to be approved for this indication. Paroxetine mesylate (Pexeva) and paroxetine hydrochloride (Paxil, and generics) are marketed in higher doses for treatment of depression and other psychiatric disorders.