An oral nonopioid analgesic is often sufficient for acute treatment of mild to moderate migraine pain without severe nausea or vomiting. A triptan is the drug of choice for treatment of moderate to severe migraine in most patients without vascular disease. Treatment of pain when it is still mild to moderate in intensity improves headache response and reduces the risk of recurrence.

The FDA has approved the over-the-counter (OTC) sale of Narcan (Emergent), a nasal spray that delivers 4 mg of the opioid antagonist naloxone. Narcan nasal spray has been available by prescription since 2015 for emergency treatment of opioid overdose. Generic formulations of Narcan have also been approved; the manufacturers of these products will be required to switch them to OTC status and amend their labeling accordingly. Kloxxado, an 8-mg naloxone nasal spray, remains available only by prescription.

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

View the Comparison Table: Some Oral/Transdermal Opioid Analgesics

The FDA has approved a generic injectable formulation of the opioid antagonist nalmefene (Purdue) for the management of known or suspected opioid overdose. Revex, the reference product, was withdrawn from the market in 2008 for commercial reasons.

The FDA has approved Seglentis (Esteve/Kowa), an oral combination of tramadol hydrochloride, a weak opioid agonist and weak serotonin and norepinephrine reuptake inhibitor (SNRI), and celecoxib, a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID), for use in adults with acute pain that is severe enough to require an opioid and for which alternative treatment options are inadequate.

The FDA has approved a higher-dose injectable formulation of the opioid antagonist naloxone (Zimhi – Adamis) for emergency treatment of opioid overdose. A single IM or SC injection of the new formulation delivers 5 mg of naloxone; injectable formulations that deliver 0.4 mg or 2 mg of the drug have been available for years. Naloxone is also available in intranasal formulations for the same indication (see Table 1).

The FDA has approved a fixed-dose combination of the amide local anesthetic bupivacaine and the nonsteroidal anti-inflammatory drug (NSAID) meloxicam as an extended-release (ER) solution (Zynrelef – Heron) for single-dose, intraoperative, soft-tissue or periarticular instillation to provide postsurgical analgesia for up to 72 hours in adults undergoing foot and ankle, small-to-medium open abdominal, or lower extremity total joint arthroplasty surgical procedures.

The FDA has approved a higher-dose intranasal naloxone formulation (Kloxxado – Hikma) for emergency treatment of opioid overdose. A single spray of the new formulation delivers 8 mg of naloxone; a formulation that delivers 4 mg per spray (Narcan) was approved in 2015.

Oliceridine (Olinvyk - Trevena), an IV opioid agonist, has been approved by the FDA for management of acute pain severe enough to require an opioid and for which alternative treatment options are inadequate.

A fixed-dose combination of orphenadrine citrate, aspirin, and caffeine (Orphengesic Forte – Galt; previously available as Norgesic Forte) has been approved as a prescription drug by the FDA for treatment of mild to moderate pain caused by acute musculoskeletal disorders. Single-ingredient generic orphenadrine citrate is available by prescription in oral and injectable formulations and has been used for years as an adjunct for treatment of acute musculoskeletal pain. Orphengesic Forte is being marketed as a non-opioid alternative for pain relief.

The FDA now requires boxed warnings in the package inserts of benzodiazepines describing the potential for these drugs to be abused and misused and to cause addiction and physical dependence. Benzodiazepine labels have contained a boxed warning about a risk of serious drug interactions with opioids since 2016.

The FDA has required new warnings in the labels of gabapentin (Neurontin, and others) and pregabalin (Lyrica, Lyrica CR, and generics) about the risk of life-threatening or fatal respiratory depression in patients with respiratory risk factors. Respiratory risk factors include chronic obstructive pulmonary disease (COPD) and concurrent use of opioids or other CNS depressants. Elderly patients are also at increased risk.

Opioids delay gastric emptying and the absorption of many oral drugs, including the P2Y₁₂ inhibitors clopidogrel (Plavix, and generics), prasugrel (Effient, and generics), and ticagrelor (Brilinta), which are commonly used for initial treatment of acute coronary syndrome (ACS). An article in our February 25, 2019 issue reviewed studies showing that coadministration of opioids delayed and decreased absorption of oral P2Y₁₂ inhibitors and increased platelet reactivity. Recently published clinical outcomes data may add to these concerns.

Cannabis (marijuana) contains more than 60 pharmacologically active cannabinoids; delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best known. THC is the main psychoactive constituent of cannabis. CBD, unlike THC, does not produce intoxication or euphoria.

The FDA has approved Apadaz (KemPharm), a short-acting, fixed-dose combination of benzhydrocodone and acetaminophen, for short-term management (≤14 days) of acute pain severe enough to require an opioid and for which alternative treatment options are inadequate. Benzhydrocodone is a prodrug of hydrocodone. Fixed-dose combinations of short-acting hydrocodone and acetaminophen or ibuprofen have been available for years and are the most abused opioid products in the US. Apadaz was developed under the presumption that inclusion of the inactive prodrug would reduce the potential for abuse of the combination by non-oral routes such as smoking, snorting, or injection, but the FDA did not approve Apadaz as an abuse-deterrent formulation.

Some readers have questioned our characterization of opioid withdrawal as not life-threatening (Med Lett Drugs Ther 2018; 60:137). While death during opioid withdrawal is unusual, it is possible — for example, due to severe untreated dehydration, withdrawal-induced suicidality, or rare myocardial events. We probably should have said that opioid withdrawal is generally not life-threatening. We will make that addition to the article as it appears on our website.

The FDA has approved Roxybond (Daiichi Sankyo), an short-acting (SA) oxycodone formulation with abuse-deterrent properties, for treatment of pain requiring management with an opioid. Roxybond is the first SA opioid to be approved as an abuse-deterrent product. Oxaydo, another IR oxycodone formulation, has properties that discourage its intranasal and intravenous use, but is not considered an abuse-deterrent product by the FDA. Use of opioids for treatment of pain was reviewed in a recent issue.

Pharmacologic management of opioid withdrawal symptoms can reduce the intensity of drug craving and improve treatment retention in patients with opioid use disorder who will receive maintenance treatment. Withdrawal management without subsequent maintenance treatment is associated with high rates of relapse, overdose death, and HIV and/or hepatitis C virus infection. Several guidelines on management of opioid withdrawal are available. Maintenance treatment of opioid use disorder was reviewed in a previous issue.

View Expanded Table: Some Drugs for Management of Opioid Withdrawal Symptoms

The FDA has approved lofexidine (Lucemyra – US WorldMeds/Salix), a centrally acting alpha₂ receptor agonist, to manage withdrawal symptoms in adults abruptly stopping opioid use. Available in the UK since 1992, lofexidine is the first nonopioid to be approved in the US for management of opioid withdrawal symptoms. Clonidine (Catapres, and generics), another central alpha₂ receptor agonist, has been used off-label for this indication for many years.

Use of nonopioid drugs for pain was reviewed in a previous issue. For many types of moderate to severe acute pain, acetaminophen and/or an NSAID may be as effective as an opioid. Immediate-release formulations of full opioid agonists should generally be used for acute pain that is severe enough to require treatment with an opioid. Use of extended-release or long-acting opioid formulations initially and treatment durations >1 week have been associated with an increased risk of unintended long-term use.

The FDA has approved a subcutaneous (SC) extended-release formulation of the mu-opioid receptor partial agonist and kappa-opioid receptor antagonist buprenorphine (Sublocade – Indivior) for once-monthly treatment of moderate to severe opioid use disorder. Sublocade is the first injectable buprenorphine product to be approved in the US. Buprenorphine is also available in sublingual formulations with or without the opioid antagonist naloxone, in a buccal formulation with naloxone, and as a subdermal implant (Probuphine).

View the Comparison Table: Some Nonopioid Analgesics for Pain

Nonopioid drugs can be used in the treatment of many nociceptive and neuropathic pain conditions. Use of opioids for pain will be reviewed in a future issue.

Opioid use disorder is a chronic, relapsing disease with both physical and psychiatric components. It is associated with economic hardship, social isolation, incarceration, increased rates of blood-borne infections such as HIV and viral hepatitis, adverse pregnancy outcomes, and increased mortality. According to the CDC, there were 33,091 deaths related to opioid overdose in the US in 2015, more than in any previous year. Several guidelines on the management of opioid use disorder have recently been published.

Development of abuse-deterrent opioid products, including reformulation of existing products, has become a priority for drug manufacturers and public health advocates. Since our last article on this subject, several new abuse-deterrent opioid formulations have been approved by the FDA, including an oxycodone tablet formulation (Roxybond – Inspirion) that is the first immediate-release opioid product FDA-approved to include claims of abuse deterrence in its labeling. No opioid formulation prevents consumption of a large number of intact dosage units, the most common method of abuse. Abuse-deterrent formulations have one or more properties that make their intentional nontherapeutic use more difficult, less attractive, or less rewarding.

The FDA has approved Arymo ER (Egalet), a new extended-release, abuse-deterrent tablet formulation of morphine sulfate, for management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate. Arymo ER can only be marketed to deter abuse by injection because another single-entity, extended-release morphine product, MorphaBond, which has not been marketed to date, has marketing exclusivity for deterrence of abuse by the intranasal route through October 2018.

The FDA has approved subdermal implants of the partial opioid agonist buprenorphine (Probuphine – Titan) for maintenance treatment of opioid dependence in patients stabilized on low to moderate doses of transmucosal buprenorphine. Probuphine was designed to provide continuous low levels of buprenorphine for 6 months and to safeguard against illicit use of the drug.

The FDA has approved Xtampza ER (Collegium), a new extended-release, abuse-deterrent capsule formulation of oxycodone, for management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate.

Belbuca (Endo), a buccal formulation of the partial opioid agonist buprenorphine, has been approved by the FDA for management of pain severe enough to require daily, around-the-clock, long-term opioid treatment. Buprenorphine is also available as a transdermal patch (Butrans) and in a parenteral formulation (Buprenex, and generics) for treatment of pain. A sublingual formulation of buprenorphine and buccal and sublingual formulations containing buprenorphine and the opioid antagonist naloxone are approved for use as alternatives to methadone for treatment of opioid dependence.

The FDA has approved Vivlodex (Iroko), a low-dose formulation of the nonsteroidal anti-inflammatory drug meloxicam (Mobic, and generics), for management of osteoarthritis pain. According to the manufacturer, the new formulation aligns with stronger FDA warnings about the cardiovascular risks of NSAIDs and the recommendation to use the lowest possible doses of these drugs.

Development of abuse-deterrent opioid products, including reformulation of existing products, has become a priority for drug manufacturers and public health advocates. Three available opioid formulations, OxyContin (Purdue), Embeda (Pfizer), and Hysingla ER (Purdue), now include claims of abuse deterrence in their package inserts.

The FDA has approved a buccal film formulation of the partial opioid agonist buprenorphine combined with the opioid antagonist naloxone (Bunavail – BioDelivery Sciences) for maintenance treatment of opioid dependence. Sublingual tablet and film formulations of the same combination were approved earlier. The manufacturer of Bunavail claims that the new product is superior to sublingual formulations because of the convenience of buccal administration and better absorption into the blood, permitting use of lower doses.

Many different drugs are used for treatment of osteoarthritis pain, but none of them prevent progression of the disease. Many nonpharmacologic approaches are available as well, including weight management, exercise, physical therapy, assistive devices, and total joint arthroplasty. New guidelines for the management of osteoarthritis have recently been published.

The FDA has approved a fixed-dose extended-release formulation of oxycodone and acetaminophen (Xartemis XR – Mallinckrodt) for oral treatment of acute pain severe enough to require an opioid. Oxycodone is available in the US as a single entity in oral immediate-release (Oxecta, and others) and extendedrelease (OxyContin) formulations. Immediate-release oxycodone is also available in combination with aspirin (Percodan, and others), acetaminophen (Percocet, and others), or ibuprofen (see Table 1).

A recent Medical Letter article reported renewed interest in the intranasal administration (off-label) of the opioid antagonist naloxone because of an increase in deaths from opioid overdose in the US.1 Now the FDA has approved a more practical alternative for emergency treatment of life-threatening opioid overdose in adults and children: a single-dose naloxone auto-injector (Evzio – Kaleo) for intramuscular or subcutaneous use.

Evzio will be available in kits containing two prefilled 0.4-mg auto-injectors with voice guidance and a "trainer" device that also has voice guidance, but does not contain medication or a needle. The manufacturer has not published a price for Evzio to date, but news reports indicate that each kit could cost hundreds of dollars, compared to about $20 for a standard 0.4-mg injectable dose of naloxone, which can be given intranasally.

1. Intranasal naloxone for treatment of opioid overdose. Med Lett Drugs Ther 2014; 56:21.

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The recent increase in deaths from heroin overdose in the US has led to renewed interest in the opioid antagonist naloxone, particularly in making it available as an intranasal spray to paramedics and possibly to relatives and close friends of heroin users. Intravenous (IV) administration is preferred, but peripheral venous access may be difficult to obtain in IV drug abusers, and exposure to their blood may be hazardous.

Treatment of migraine in the emergency department, which may involve use of intravenous drugs, is not discussed here.

A new sublingual tablet formulation of the partial opioid agonist buprenorphine combined with the opioid antagonist naloxone (Zubsolv – Orexo) has been approved by the FDA for maintenance treatment of opioid dependence. Zubsolv tablets have relatively greater bioavailability than previously approved sublingual film (Suboxone) and sublingual tablet formulations of buprenorphine/naloxone and, according to an open-label survey, they taste better. The new tablets are smaller and dissolve faster than other tablet formulations, and they are individually sealed in child-resistant packaging.1

Buprenorphine is a Schedule III controlled substance that can be prescribed in an office setting by qualified physicians who register with the Substance Abuse and Mental Health Services Administration.2

Zubsolv is available as triangular tablets containing 1.4 mg of buprenorphine and 0.36 mg of naloxone and round tablets containing 5.7 mg of buprenorphine and 1.4 mg of naloxone, which achieve plasma concentrations of buprenorphine equivalent to those with the 2/0.5-mg and 8/2-mg strengths of other buprenorphine/naloxone tablets. A package of Zubsolv 5.7/1.4-mg tablets costs the same ($211) as a box of Suboxone 8/2-mg films. A bottle of generic buprenorphine/naloxone 8/2-mg tablets costs $250.3

1. A Fischer et al. Pharmaceutical and pharmacokinetic characterization of a novel sublingual buprenorphine/naloxone tablet formulation in healthy volunteers. Drug Dev Ind Pharm 2013 Oct 7 (epub).

2. Buprenorphine: an alternative to methadone. Med Lett Drugs Ther 2003; 45:13.

3. Approximate wholesale acquisition cost (WAC) of 30 tablets or films. Source: $ource® Monthly (Selected from FDB MedKnowledge™) October 5, 2013. Reprinted with permission by FDB, Inc. All rights reserved. ©2013. www.fdbhealth.com/policies/drug-pricing-policy. Actual retail prices may be higher.

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Pain can be acute or chronic. The two major types of chronic pain are nociceptive pain and neuropathic pain. Nociceptive pain can be treated with nonopioid analgesics or opioids. Neuropathic pain is less responsive to opioids and is often treated with adjuvant drugs such as antidepressants and antiepileptics. Combining different types of analgesics may provide an additive analgesic effect without increasing adverse effects.

The FDA has approved the opioid agonist hydromorphone in a once-daily extended-release (ER) oral tablet formulation (Exalgo – Covidien) for the management of moderate to severe pain in opioid-tolerant patients requiring continuous, long-term therapy. Another hydromorphone ER formulation (Palladone – Purdue) was available previously, but was withdrawn from the market because taking it with alcohol could interfere with the extended-release mechanism and lead to rapid release of potentially lethal amounts of the drug ("dose-dumping").

The FDA has approved the partial opioid agonist buprenorphine in a transdermal formulation (Butrans – Purdue) for treatment of moderate to severe chronic pain. Buprenorphine has been available in the US for years in parenteral formulations for pain and in sublingual tablets for opioid dependence.1 Transdermal buprenorphine has been available in Europe for several years.2

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 required manufacturers of propoxyphene-containing products (Darvon, and others) to strengthen boxed warnings to include the potential for overdose.1 This action followed disclosure of fatal overdoses linked to propoxyphene-containing products taken alone or concurrently with other CNS depressants, including alcohol. Many of the overdoses occurred in patients with a history of emotional instability or suicide attempts. Accumulation of metabolites of propoxyphene can lead to central nervous system, cardiac and respiratory depression; convulsions and cardiotoxicity have occurred.

A Schedule IV controlled substance, propoxyphene is a weak full agonist opioid indicated for relief of mild to moderate pain.2 It is often prescribed in combination with acetaminophen (Darvocet, and others). One reasonable alternative would be codeine with acetaminophen; 32 mg of codeine has an analgesic effect similar to that of 65 mg of propoxyphene. Another would be 400 mg of ibuprofen, which may be more effective than either propoxyphene or codeine combined with acetaminophen.

1. FDA News Release. FDA takes actions on Darvon, other pain medications containing propoxyphene. Available at www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm170769.html. Accessed August 23, 2010.

2. Drugs for pain. Treat Guidel Med Lett 2010; 92:25.

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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.

An intraveneous (IV) formulation of ibuprofen (Caldolor - Cumberland) was recently approved by the FDA for use in adults. It can be administered alone for treatment of mild to moderate pain or as an adjunct to opioid analgesics for moderate to severe pain. It is also approved for reduction of fever.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment could also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

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The FDA has approved subcutaneous injection of methylnaltrexone (Relistor - Wyeth/Progenics), a selective mu-opioid receptor antagonist, for treatment of opioid-induced constipation in patients with advanced illness (such as incurable cancer or end-stage chronic obstructive pulmonary disease) who are receiving palliative care.

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.

The FDA has approved a transmucosal tablet formulation of fentanyl citrate (Fentora - Cephalon) for management of breakthrough pain in opioid-tolerant patients with cancer. An oral transmucosal fentanyl lozenge on a stick (Actiq, and others) is also available for this indication, and is widely used off-label for chronic, non-cancer pain as well.

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.

Oxymorphone hydrochloride, a semi-synthetic opioid agonist, has been available for many years in the US as Numorphan (Endo) for parenteral use and as a rectal suppository. Now it has been approved by the FDA for oral administration as an immediate-release (IR) tablet (Opana) for treatment of moderate to severe acute pain, and as an extended-release tablet (Opana ER) for treatment of moderate to severe pain in patients requiring continuous opioid treatment for an extended period of time.

Every pharmaceutical drug is a dose-dependent poison. This article describes the clinical presentation and treatment of some dangerous overdoses commonly reported in adults.

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.

Pregabalin (Lyrica - Pfizer), a structural analog of gamma-aminobutyric acid (GABA) similar to gabapentin (Neurontin - Pfizer, and others), which recently became available generically, has been approved by the FDA for treatment of neuropathic pain associated with postherpetic neuralgia (PHN) and diabetic peripheral neuropathy (DPN), and for adjunctive treatment of partial onset seizures in adults with epilepsy.

Ropinirole (Requip - GlaxoSmithKline), a dopamine agonist already available for treatment of Parkinson's disease, is now the first drug approved by the FDA for treatment of moderate to severe restless legs syndrome (RLS).

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).

Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

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).

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.

The FDA has approved the marketing of buprenorphine in sublingual tablets (Reckitt Benckiser) both alone (Subutex) and with naloxone (Suboxone) for treatment of opioid dependence. Previously available only for parenteral use in treatment of pain (Buprenex, and others), it offers an alternative to methadone (Dolophine, and others), which is now often abused (New York Times, February 9, 2003; page 1). As a schedule III narcotic, buprenorphine will be subject to fewer prescribing restrictions than a schedule II drug such as methadone (MJ Kreek and FJ Vocci, J Subst Abuse Treat 2002; 23:93).w1150a

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.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment may also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

Acute toxic reactions to drugs of abuse continue to be important problems. Some patients may have mixed intoxications with complex combinations of signs and symptoms.

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.

Reports of adverse interactions between drugs continue to accumulate. Recently, the FDA has expanded the recommendations on drug interactions found in the package inserts of new drugs.

Acute toxic reactions to drugs of abuse continue to be important problems. Since the last Medical Letter article on this subject (volume 32, page 92, 1990), new reactions and new approaches to treating them have been reported.

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.

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.

Some commonly used systemic drugs that may cause pulmonary toxicity are listed in the table below. These adverse effects may sometimes be difficult to distinguish from the underlying disease (JAD Cooper, Jr et al, Am Rev Respir Dis, 133:321, 488, 1986). Pulmonary effects that are part of a generalized reaction or are indirect effects of drugs - on respiratory muscles, for example, or on the immune system - are not included here.