Drugs for treatment of migraine are listed in Table 2 on page 9. Drugs for prevention of migraine are listed in Table 3 on page 10. Treatment of migraine in the emergency room, which may involve use of intravenous drugs, is not included here.

The FDA has approved tramadol hydrochloride extended-release (Ryzolt – Purdue) for treatment of moderate to moderately severe chronic pain in adults. Tramadol is already available in another extended-release formulation (Ultram ER) and in immediate-release tablets alone (Ultram, and others) and combined with acetaminophen (Ultracet, and others).

Pain can be acute or chronic. Chronic pain has been broadly classified into two types: nociceptive and neuropathic. Nociceptive pain can be treated with nonopioid analgesics or opioids. Neuropathic pain is less responsive to opioids; adjuvant medicines such as antidepressants and anticonvulsants are often used to treat neuropathic pain. Combining different types of analgesics may provide an additive analgesic effect without increasing adverse effects.

The FDA has approved an agonist/antagonist combination of morphine and naltrexone (Embeda – King) for treatment of chronic moderate to severe pain requiring around-the-clock analgesia for an extended period of time. The addition of naltrexone is intended to prevent abuse of morphine.

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

Concerns have surfaced again at the FDA and in the media about the safety of acetaminophen and the multiplicity of products on the market in the US that contain various amounts of it.

Duloxetine (Cymbalta - Lilly) is the second drug to be approved by the FDA for treatment of fibromyalgia. Pregabalin (Lyrica), which is also approved for treatment of neuropathic pain and epilepsy, was the first. Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) that is already marketed for treatment of depression and diabetic neuropathy.

Some drugs for treatment of migraine attacks are listed in table 2 on page 18. Drugs for prevention of migraine are listed in table 3 on page 20. Treatment of migraine in the emergency room, which may involve use of intravenous drugs, is not included here.

Pain can be acute or chronic. Chronic pain has been broadly classified into two types: nociceptive and neuropathic. Nociceptive pain is generally treated with nonopioid analgesics and opioids. Antidepressants and anticonvulsants have been used to treat neuropathic pain. Combining two different types of analgesics may nprovide an additive analgesic effect without increasing adverse effects.

The physiologic changes that occur with aging can affect the pharmacokinetics and pharmacodynamics of many prescription and over-the-counter drugs, increasing the likelihood of adverse effects.

A fixed-dose combination of oxycodone 5 mg and ibuprofen 400 mg (Combunox - Forest Laboratories) is now available and is being heavily advertised for short-term treatment of moderate to severe acute pain.

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.

The Medical Letter review of Palladone (hydromorphone HCl) extended-release capsules (March 14, 2005) warned that a lethal dose could be released if the new formulation was taken with alcohol. Because of that risk, the FDA asked the manufacturer (Purdue) to withdraw the drug from the market (FDA News. July 13, 2005; FDC Reports – “The Pink Sheet” July 18, 2005; 67:3).

A once-daily extended-release (ER) oral formulation of the opioid analgesic hydromorphone hydrochloride (Palladone - Purdue Pharma) has been approved by the FDA for treatment of opioid-tolerant patients with persistent moderate to severe pain. Hydromorphone HCl, a semisynthetic congener of morphine and active metabolite of hydrocodone that has been used since the 1920s, is also available in immediate-release oral, injectable and suppository forms (Dilaudid, and others).

In our January 17 issue, a short article on NSAID alternatives mentioned that tramadol (Ultram, and others), a weak opioid analgesic, could be helpful for some patients. A few readers have commented that we should have said something about its drawbacks. The need for slow titration in dosage limits the drug's use for treatment of acute pain. Seizures have been reported with tramadol; patients taking an antidepressant or an antipsychotic drug may be at increased risk. Tramadol is not a controlled substance, but psychological and physical dependence have occurred.

Patients taking nonsteroidal anti-inflammatory drugs (NSAIDs) may be asking their health care providers if they should continue, and some may be asking for alternatives. For most patients taking nonspecific NSAIDs, it would be reasonable to continue. For those who are taking the COX-2 selective celecoxib (Celebrex) because they cannot tolerate the gastrointestinal (GI) effects of nonspecific NSAIDs, it seems reasonable to continue at doses no higher than 100 mg b.i.d. or 200 mg once daily; at these dosages cardiovascular risk has been no higher than with placebo. All NSAIDs, including COX-2 inhibitors, can decrease renal blood flow and cause fluid retention, hypertension and renal failure, especially in the elderly and in patients who take diuretics. The unpublished study that led to an FDA alert on an increased cardiovascular risk with naproxen (Naprosyn, and others) was conducted in patients older than 70. See NSAID addendum

With the removal of Vioxx from the market and concerns about cardiovascular toxicity with other selective COX-2 inhibitors, patients are looking for safe alternatives, and manufacturers of other drugs are looking for additional market share. The COX-2 inhibitors first became popular because they have less upper GI toxicity than older less selective NSAIDs, at least in the short term, in patients not taking aspirin.

Three types of analgesic drugs are available: non-opioids, including aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen; opioids; and adjuvant drugs that are not usually thought of as analgesics, such as antidepressants, which can act as adjuvants when given with NSAIDs or opioids, or have analgesic activity of their own in some types of pain. Combining two different types of analgesics may provide an additive analgesic effect without necessarily increasing adverse effects.

Gabapentin (Neurontin - Pfizer), which has been available in the US since 1994, is approved by the FDA only for treatment of partial epilepsy and postherpetic neuralgia, but is widely used off-label for a number of other indications, especially neuropathic pain syndromes. According to one report, among Medicaid recipients in Florida receiving gabapentin, 71% of prescriptions were for chronic pain and 8% for seizures and neuralgia ("The Pink Sheet" February 2, 2004; 66:30).

Three types of analgesic drugs are available: first, non-opioids, including aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen; second, opioids; and third, drugs not usually thought of as analgesics, which act as adjuvants when given with NSAIDs or opioids, or have analgesic activity of their own in some types of pain. Non-opioids can be given concurrently with opioids for an additive analgesic effect.

Three new 5-HT1 receptors agonissts ('triptans') have been marketed recently for treatment of migraine. Some drugs for prevention of migraine are listed in the table on page 99. Treatment of migraine in the emergency room, which may involve use of intravenous drugs, is not included here.

Tramadol hydrochloride (Ultram - Ortho-McNeil), a centrally-acting analgesic marketed in Germany since 1977, was recently approved by the US Food and Drug Administration for oral treatment of moderate to moderately severe pain. Despite some opioid activity, tramadol has not been scheduled as a controlled substance.

Drugs are used both to prevent and treat migraine symptoms. The effectiveness of such use can be difficult to evaluate, even with double-blind controlled trials, because migraine is episodic, response to placebo is frequent, and patients vary in response to a given agent (KMA Welch, N Engl J Med, 329:1476, 1993; SD Silberstein and RB Lipton, Neurology, 44 suppl 7:S6, Oct 1994).

Three types of analgesic drugs are available in the USA: first, aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen; second, opioids; and third, drugs not usually thought of as analgesics, which act as adjuvants when given with NSAIDs or opioids, or have analgesic activity of their own in some types of pain. (American Pain Society, Principles of analgesic Use, 3rd ed, Skokie, illinois: American pain society, 1992).

Fentanyl, a synthetic opioid previously available for parenteral use in anesthesia (Sublimaze), has now been marketed in a controlled-release transdermal formulation (Duragesic - Janssen) for use in patients with chronic pain severe enough to require opioid analgesia. It is not recommended for treatment of postoperative pain because of the drug's slow onset and prolonged duration of action.

Capsaicin, a vanillyl alkaloid found in hot peppers and related plants, is now available without a prescription as Zostrix-HP (GenDerm) for topical relief of pain due to diabetic neuropathy, herpes zoster, or arthritis. The new formulation contains 0.075% capsaicin; the drug was previously available in a 0.025% concentration as Zostrix.

Etodolac (Lodine - Wyeth-Ayerst), a nonsteroidal anti-inflammatory drug (NSAID) available in Europe for several years, was recently approved by the U.S. Food and Drug Administration for use in osteoarthritis and as a general-purpose analgesic. It has not been approved for treatment of rheumatoid arthritis.

Dezocine (Dalgan - Astra), a new synthetic opioid agonist/antagonist structurally related to pentazocine (Talwin), was recently approved for parenteral use as an analgesic by the US Food and Drug Administration.

Ketorolac (kee'; toe role ak) tromethamine (Toradol), manufactured by Syntex but also marketed by Roche, is the first parenteral nonsteroidal anti-inflammatory drug (NSAID) to become available for analgesic use in the USA. Parenteral indomethacin (Indocin I.V.) has been marketed here since 1985, but only for treatment of patent ductus arteriosus in newborn infants. Other parenteral NSAIDs are available in other parts of the world, but low potency, poor aqueous solubility, and substantial tissue irritation on injection have limited their usefulness. Ketorolac has been approved by the US Food and Drug Administration for intramuscular (IM) treatment of moderate to severe pain.