Equianalgesic

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An equianalgesic chart is a conversion chart that lists equivalent doses of analgesics (drugs used to relieve pain). Equianalgesic charts are used for calculation of an equivalent dose (a dose which would offer an equal amount of analgesia) between different analgesics. [1] Tables of this general type are also available for NSAIDs, benzodiazepines, depressants, stimulants, anticholinergics and others.

Contents

Format

Equianalgesic tables are available in different formats, such as pocket-sized cards for ease of reference. [1] A frequently-seen format has the drug names in the left column, the route of administration in the center columns and any notes in the right column. [2] [3]

Purpose

There are several reasons for switching a patient to a different pain medication. These include practical considerations such as lower cost or unavailability of a drug at the patient's preferred pharmacy, or medical reasons such as lack of effectiveness of the current drug or to minimize adverse effects. Some patients request to be switched to a different narcotic due to stigma associated with a particular drug (e.g. a patient refusing methadone due to its association with opioid addiction treatment). [4] Equianalgesic charts are also used when calculating an equivalent dosage of the same drug, but with a different route of administration.[ citation needed ]

Precautions

An equianalgesic chart can be a useful tool, but the user must take care to correct for all relevant variables such as route of administration, cross tolerance, half-life and the bioavailability of a drug. [5] For example, the narcotic levorphanol is 4–8 times stronger than morphine, but also has a much longer half-life. Simply switching the patient from 40 mg of morphine to 10 mg of levorphanol would be dangerous due to dose accumulation, and hence frequency of administration should also be taken into account.

There are other concerns about equianalgesic charts. Many charts derive their data from studies conducted on opioid-naive patients. Patients with chronic (rather than acute) pain may respond to analgesia differently. Repeated administration of a medication is also different from single dosing, as many drugs have active metabolites that can build up in the body. [6] Patient variables such as sex, age, and organ function may also influence the effect of the drug on the system. These variables are rarely included in equianalgesic charts. [7] [3] [8]

Opioid equivalency table

Opioids are a class of compounds that elicit analgesic (pain killing) effects in humans and animals by binding to the µ-opioid receptor within the central nervous system. The following table lists opioid and non-opioid analgesic drugs and their relative potencies. Values for the potencies represent opioids taken orally unless another route of administration is provided. As such, their bioavailabilities differ, and they may be more potent when taken intravenously.[ citation needed ]

Nonlinearities

This chart measures pain relief versus mass of medication. Not all medications have a fixed relationship on this scale. Methadone is different from most opioids because its potency can vary depending on how long it is taken. Acute use (1–3 days) yields a potency about 1.5× stronger than that of morphine and chronic use (7 days+) yields a potency about 2.5 to 5× that of morphine. Similarly, the effect of tramadol increases after consecutive dosing due to the accumulation of its active metabolite and an increase of the oral bioavailability in chronic use.[ citation needed ]

Comparison to oral morphine [lower-alpha 1]
AnalgesicStrength
(relative)
Equivalent dose
(10 mg oral morphine) [lower-alpha 2]
BioavailabilityHalf-life of active metabolites
(hours)
Oral-to-parenteral ratioSpeed of onsetDuration
Paracetamol (non-opioid)13603600 mg63–89%1–437 min (PO); 8 min (IV)5–6 hours
Aspirin (NSAID, non-opioid)13603600 mg80–100%3.1–9
Ibuprofen [10] (NSAID, non-opioid)12222220 mg87–100%1.3–3
Diflunisal (NSAID, non-opioid)11601600 mg80–90%8–12
Naproxen [10] (NSAID, non-opioid)11381380 mg95%12–24
Piroxicam (NSAID non-opioid)1120 (est.)
Indomethacin (NSAID non-opioid)164 (est.)
Diclofenac [10] [11] (NSAID, non-opioid)110 (est.) (same as Codeine)100 mg (est.)50–60%1–4
Ketorolac [12] (NSAID, non-opioid)13 (est.)30 mg IV (est.)80–100%5–7
Nefopam (Centrally-acting non-opioid)58 (est.)16 mg IM (est.) Nefopam: 3–8, Desmethylnefopam 10–15
Dextropropoxyphene [13] 113120130–200 mg
Codeine 110320100–120 mg (PO)~90%2.5–3 (C6G 1.94; [14] morphine 2–3)15–30 min (PO)4–6 hours
Tramadol 110~100 mg75% (IR), 85–90% (ER)6.0–8.8 [15] (M1)
Opium (oral)110~100 mg~25% (morphine)2.5–3.0 (morphine, codeine)
Tilidine 110100 mg
Dihydrocodeine 1550 mg20%4
Anileridine [16] 1440 mg
Alphaprodine 141640–60 mg
Tapentadol [17] 31032 mg32% (fasting)
Pethidine (meperidine)1330 mg SC/IM/IV, 300 mg (PO)50–60%3–5
Benzylfentanyl 12
AH-7921 45
Hydrocodone 110 mg70% [18] 3.8–6 (Instant Release; PO)10–30 min (Instant Release; PO)4–6
Metopon 110 mg
Pentazocine lactate (IV) [19] 110 mg SC/IV/IM, 150 mg (PO)
Morphine (oral) 1 10 mg ~25%2–43:130 min (PO)3–6 hours
Oxycodone (oral) [20] 1.56.67 mg60-87%2–3 hours (Instant Release)(PO); 4.5 hours (Controlled Release)(PO)10–30 min (Instant Release)(PO); 1 hour (Controlled Release)(PO)3–6 hours (Instant Release)(PO); 10–12 hours (Controlled Release)(PO) [21]
Spiradoline 1.5
Nicomorphine 2–33.33–5 mg20%4
Oxycodone (IV) [22] 33.33 mg96%1.5–3 (IV)5 min (IV) [22] 2-4 hours
Morphine (IV/IM)33.33 mg100%2–33:1Instantaneously (from 5 to 15 sec; IV); 5–15 min (IM)3–7 hours
Clonitazene 33.33 mg
Methadone (acute) [23] [24] 3–42.5–3.33 mg40–90%15–602:1
Methadone (chronic) [24] 2.5–52–4 mg40–90%15–602:1
Phenazocine 4~2.5 mg
Diamorphine (Heroin; IV/IM) [25] 4–5 (iv, im) 2–2.5 (insufflated) [26] 2–2.5 mg100%<0.6 (morphine prodrug) [27] Instantaneously (from 5 to 15 sec; IV); 2 to 5 min (IM)3 to 7 hours
Dezocine 4–61.6–2.5 mg97% (IM)2.2
Hydromorphone [28] [29] [17] 10 (SC, IV, IM)
3–3.75 (PO)
0.5-0.75 mg (SC, IV, IM)
2.5 mg (PO)
Orally: 30–35%, Intranasal:

52- 58% IV/IM: 100% 62%

2–35:1
Oxymorphone [20] 10 (SC, IV, IM)
3–4(PO)
3.33 mg (PO), 0.333 mg (IV,IM & Interlaminar)PO: 10%

Buccal: 28% Sublingual:37.5% Intranasal: 43% IV, IM & IT: 100%

7.25–9.4335 min (PO), Instantaneously (from 5 to 15 sec)(IV)6–8 hours orally

2-6 hours parenteral

U-47700 7.51.5 mg1.5–3
Levorphanol [30] 81.25 mg70%11–161:1
Desomorphine (Krokodil)8–101–1.25 mg~100% (IV)2–3Instantaneously (from 5 to 15 sec)(IV); 2–5 min (IM)3–4 hours
N-Phenethylnormorphine 8–14
Alfentanyl 10–251.5 (90–111 minutes)Instantaneously (from 5 to 15 sec); 4× more rapid than fentanyl0.25 hr (15 min); up to 54 minutes until offset of effects
Trefentanil (10–25)+
Brifentanil (10–25)+
Acetylfentanyl 15
7-Hydroxymitragynine 17~0.6 mg
Furanylfentanyl 20
Butyrfentanyl 25
Enadoline 2515 µg (threshold) and 0.160 mg/kg (dissociative effects)
Buprenorphine (SL) [13] 400.25 mg30% (SL); [31] ~100% (TD); 65% (buccal); [32] [33] 48% (INS) [34] 20–70, mean 373:145 min12–24 hours
N-Phenethyl-14-ethoxymetopon 60160 µg
Phenomorphan 60–800.13–0.16 mg
N-Phenethylnordesomorphine 85
Phenaridine (50–100)−
Fentanyl 50–1000.1 mg (100 µg) IM/IV33% (SL); 92% (TD); 89% (INS); 50% (buc)0.04 (IV); 7 (TD)5 min (TD/IV)30–60 minutes (IV)
Metonitazene1000.1 mg/100 µg
Acrylfentanyl (50–100+)
Buprenorphine (Transdermal) [35] [36] 100–1150.1 mg (100 µg)30% (SL); [31] ~100% (TD); 65% (buccal); [32] [33] 48% (INS) [34] 3:145–60 minutes12–24 hours
14-Cinnamoyloxycodeinone 17777 µg
Etonitazepyne 180-19055-60 µg
Protonitazepyne 180-19055-60 µg
Remifentanil 100–20050–100 µg0.05 (3–6 min context-sensitive half-life; 7–18min elimination half-life)Instantaneously (from 5 to 15 sec)15 minutes; rapid offset of effects necessitates continuous infusion for maintenance of anesthesia
Protonitazene 20050 µg
Ocfentanil 125–25040–80 µg
Ro4-1539 240–48020-40 µg
Isotonitazene 50020 µg
Sufentanil 500–1,00010–20 µg4.4
BDPC 504~20 µg
C-8813 591
4-Phenylfentanyl 800
Etonitazene 1000-15006,6-10 µg
3-Methylfentanyl 1000-1500
N-Desetylisotonitazene 1000-20005-10 µg
Etorphine 1,000-3,0003.3–10 µg
Ohmefentanyl 6300
Acetorphine 87001.33 µg
Dihydroetorphine [37] 1,000–12,0000.83–10 µg (20–40 µg SL)
Carfentanil [38] 10,0001.0 µg7.7
2-Fluorohmefentanil18,000
4-Carboethoxyohmefentanil30,000
Ohmecarfentanil (30,000)
R-30490 (10,000–100,000)−
Lofentanil (10,000–100,000)+
14-Methoxymetopon (intraspinally) [39] (1,000,000)
PO: oral • IV: intravenous injection • IM: intramuscular injection • SC: subcutaneous injection • SL: sublingual • TD: transdermal
"Strength" is defined as analgesic potency relative to oral morphine.
Tolerance, sensitization, cross-tolerance, metabolism, and hyperalgesia may be complex factors in some individuals.
Interactions with other drugs, food and drink, and other factors may increase or decrease the effect of certain analgesics and alter their half-life.
Because some listed analgesics are prodrugs or have active metabolites, individual variation in liver enzymes (e.g., CYP2D6 enzyme) may result in significantly altered effects.

See also

Explanatory notes

  1. Approximate. There is a wide range of values in controlled trials. [9]
  2. 10 mg oral morphine is equivalent to n mg analgesic drug x, e.g. 10 mg morphine is equivalent to 3600 mg paracetamol or 1.5 mg hydromorphone

Citations

  1. 1 2 Joishy 1999.
  2. McPherson 2009, p. 5.
  3. 1 2 Natusch 2012.
  4. McPherson 2009, p. 3.
  5. McPherson 2009, p. 4.
  6. McPherson 2009, p. 8.
  7. McPherson 2009, p. 9.
  8. Anderson et al 2001.
  9. Pereira et al 2001.
  10. 1 2 3 "Dosing Guidelines for Acetaminophen and Selected NSAIDs" (PDF). Elsevier Health. Mosby. 1999. Retrieved 2022-11-22.
  11. "Diclofenac (Voltaren®) vs Naproxen (Aleve®, Naprosyn®) - eMedExpert.com". www.emedexpert.com. Retrieved 2022-11-22.
  12. Pharma Guide Pre-Work 3rd Edition
  13. 1 2 "Ch. 4 Narcotics: Synthetic Narcotics: Dextropropoxyphene". Drugs of Abuse. Drug Enforcement Administration, U.S. Department of Justice. 2005. Archived from the original on 2006-11-02.
  14. KuKanich B (February 2010). "Pharmacokinetics of acetaminophen, codeine, and the codeine metabolites morphine and codeine-6-glucuronide in healthy Greyhound dogs". J. Vet. Pharmacol. Ther. 33 (1): 15–21. doi:10.1111/j.1365-2885.2009.01098.x. PMC   2867071 . PMID   20444020.
  15. "ULTRAM® (tramadol hydrochloride) Tablets Full Prescribing Information" (PDF). US Food and Drug Administration. Ortho-McNeil Pharmaceutical, Inc. March 2008. p. 4. Retrieved December 28, 2016. The mean terminal plasma elimination half-lives of racemic tramadol and racemic M1 are 6.3 ± 1.4 and 7.4 ± 1.4 hours, respectively. The plasma elimination half-life of racemic tramadol increased from approximately six hours to seven hours upon multiple dosing.
  16. "Anileridine". DrugBank Version: 3.0. DrugBank.
  17. 1 2 Cupp 2012.
  18. Zacny JP, Gutierrez S (April 2009). "Within-subject comparison of the psychopharmacological profiles of oral hydrocodone and oxycodone combination products in non-drug-abusing volunteers". Drug Alcohol Depend. 101 (1–2): 107–14. doi:10.1016/j.drugalcdep.2008.11.013. PMID   19118954.
  19. "TALWIN (pentazocine lactate) injection, solution". DailyMed. National Institute of Health. Retrieved 2011-12-10.
  20. 1 2 "Equianalgesic Conversion". GlobalRPH.
  21. Sunshine, A., Olson, N., Colon, A., Rivera, J., Kaiko, R.F., Fitzmartin, R.D., Reder, R.F., Goldenheim, P.D. (July 1996). "Analgesic Efficacy of Controlled-Release Oxycodone in Postoperative Pain". Journal of Clinical Pharmacology. 36 (7): 595–603. doi:10.1002/j.1552-4604.1996.tb04223.x. PMID   8844441. S2CID   35076787.
  22. 1 2 Silvasti M, Rosenberg P, Seppälä T, Svartling N, Pitkänen M (May 1998). "Comparison of analgesic efficacy of oxycodone and morphine in postoperative intravenous patient-controlled analgesia". Acta Anaesthesiologica Scandinavica. 42 (5): 576–580. doi:10.1111/j.1399-6576.1998.tb05169.x. PMID   9605375. S2CID   25763059 . Retrieved 10 August 2022.
  23. Tabla de equivalencia opiáceos
  24. 1 2 Manfredonia JF (March 2005). "Prescribing methadone for pain management in end-of-life care". J Am Osteopath Assoc. 105 (3 Suppl 1): S18–21. PMID   18154194.[ permanent dead link ] Table 2: Conversion Ratio of Oral Morphine to Methadone.
  25. Reichle CW, Smith GM, Gravenstein JS, Macris SG, Beecher HK (April 1962). "Comparative analgesic potency of heroin and morphine in postoperative patients". J. Pharmacol. Exp. Ther. 136 (1): 43–6. PMID   14491157.
  26. Cone EJ, Holicky BA, Grant TM, Darwin WD, Goldberger BA (October 1993). "Pharmacokinetics and pharmacodynamics of intranasal 'snorted' heroin". Journal of Analytical Toxicology. 17 (6): 327–337. doi:10.1093/jat/17.6.327. ISSN   0146-4760. PMID   8271778.
  27. Sawynok J (January 1986). "The therapeutic use of heroin: a review of the pharmacological literature". Canadian Journal of Physiology and Pharmacology. 64 (1): 1–6. doi:10.1139/y86-001. PMID   2420426.
  28. Toronto Surgery 2014.
  29. Walker 2001.
  30. "Levorphanol". DrugBank Version: 3.0. DrugBank.
  31. 1 2 Mendelson J, Upton RA, Everhart ET, Jacob P 3rd, Jones RT (1997). "Bioavailability of sublingual buprenorphine". Journal of Clinical Pharmacology. 37 (1): 31–7. doi:10.1177/009127009703700106. PMID 9048270
  32. 1 2 "Buprenorphine / Naloxone Buccal Film (BUNAVAIL) C-III" (PDF). Pharmacy Benefits Management (PBM) Services. September 2014.
  33. 1 2 BUNAVAIL (buprenorphine and naloxone) buccal film, CIII [prescribing information online] . BioDelivery BioDelivery Sciences International, Inc. (BDSI), Raleigh, NC. Jun 2014.
  34. 1 2 Eriksen J, Jensen NH, Kamp-Jensen M, Bjarnø H, Friis P, Brewster D (1989). "The systemic availability of buprenorphine administered by nasal spray". J. Pharm. Pharmacol. 41 (11): 803–5. doi:10.1111/j.2042-7158.1989.tb06374.x
  35. Khanna, IK; Pillarisetti, S (2015). "Buprenorphine - an attractive opioid with underutilized potential in treatment of chronic pain". Journal of pain research. 8: 859–70. doi:10.2147/JPR.S85951. PMID 26672499
  36. Cote, J; Montgomery, L (July 2014). "Sublingual buprenorphine as an analgesic in chronic pain: a systematic review". Pain medicine (Malden, Mass.). 15 (7): 1171–8. doi:10.1111/pme.12386. PMID 24995716
  37. Ohmori S, Morimoto Y (2002). "Dihydroetorphine: a potent analgesic: pharmacology, toxicology, pharmacokinetics, and clinical effects". CNS Drug Reviews. 8 (4): 391–404. doi:10.1111/j.1527-3458.2002.tb00236.x. ISSN   1080-563X. PMC   6741694 . PMID   12481194. Dihydroetorphine (DHE) is one of the strongest analgesic opioid alkaloids known; it is 1000 to 12,000 times more potent than morphine. ...
       MOR is the most commonly used opioid analgesic for pain relief, and its oral daily dose (20 to 1000 mg) is relatively high (44). On the other hand, DHE produces rapid analgesic effects at an extremely low dose, 20 ìg sublingually in humans (60, 78). ...
  38. "Carfentanil". DrugBank Version: 3.0. DrugBank.
  39. King MA, Su W, Nielan CL, Chang AH, Schütz J, Schmidhammer H, Pasternak GW (17 January 2003). "14-Methoxymetopon, a very potent μ-opioid receptor-selective analgesic with an unusual pharmacological profile". European Journal of Pharmacology. 459 (2): 205. doi:10.1016/s0014-2999(02)02821-2. PMID   12524147 . Retrieved 19 February 2024.

General and cited references

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Related Research Articles

<span class="mw-page-title-main">Analgesic</span> Any member of the group of drugs used to achieve analgesia, relief from pain

An analgesic drug, also called simply an analgesic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in some instances eliminate, sensation, although analgesia and anesthesia are neurophysiologically overlapping and thus various drugs have both analgesic and anesthetic effects.

<span class="mw-page-title-main">Hydrocodone</span> Opioid drug used in pain relief

Hydrocodone, also known as dihydrocodeinone, is a semisynthetic opioid used to treat pain and as a cough suppressant. It is taken by mouth. Typically it is dispensed as the combination acetaminophen/hydrocodone or ibuprofen/hydrocodone for pain severe enough to require an opioid and in combination with homatropine methylbromide to relieve cough. It is also available by itself in a long-acting form under the brand name Zohydro ER, among others, to treat severe pain of a prolonged duration. Hydrocodone is a controlled drug: in the United States a Schedule II Controlled Substance.

<span class="mw-page-title-main">Methadone</span> Opioid medication

Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid use disorder. It is used to treat chronic pain, and it is also used to treat addiction to heroin or other opioids. Prescribed for daily use, the medicine relieves cravings and removes withdrawal symptoms. Withdrawal management using methadone can be accomplished in less than a month, or it may be done gradually over a longer period of time, or simply maintained for the rest of the patient's life. While a single dose has a rapid effect, maximum effect can take up to five days of use. After long-term use, in people with normal liver function, effects last 8 to 36 hours. Methadone is usually taken by mouth and rarely by injection into a muscle or vein.

<span class="mw-page-title-main">Tramadol</span> Medication of the opioid type, patented 1972

Tramadol, sold under the brand name Ultram among others, is an opioid pain medication and a serotonin–norepinephrine reuptake inhibitor (SNRI) used to treat moderately severe pain. When taken by mouth in an immediate-release formulation, the onset of pain relief usually begins within an hour. It is also available by injection. It is available in combination with paracetamol (acetaminophen).

<span class="mw-page-title-main">Hydromorphone</span> Opioid medication used for pain relief

Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is a morphinan opioid used to treat moderate to severe pain. Typically, long-term use is only recommended for pain due to cancer. It may be used by mouth or by injection into a vein, muscle, or under the skin. Effects generally begin within half an hour and last for up to five hours. A 2016 Cochrane review found little difference in benefit between hydromorphone and other opioids for cancer pain.

<span class="mw-page-title-main">Opioid</span> Psychoactive chemical

Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work in the brain to produce a variety of effects, including pain relief. As a class of substances, they act on opioid receptors to produce morphine-like effects.

<span class="mw-page-title-main">Opioid use disorder</span> Medical condition

Opioid use disorder (OUD) is a substance use disorder characterized by cravings for opioids, continued use despite physical and/or psychological deterioration, increased tolerance with use, and withdrawal symptoms after discontinuing opioids. Opioid withdrawal symptoms include nausea, muscle aches, diarrhea, trouble sleeping, agitation, and a low mood. Addiction and dependence are important components of opioid use disorder.

<span class="mw-page-title-main">Buprenorphine</span> Opioid used to treat pain & opioid use disorder

Buprenorphine, sold under the brand name Subutex among others, is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection, as a skin patch (transdermal), or as an implant. For opioid use disorder, the patient must have moderate opioid withdrawal symptoms before buprenorphine can be administered under direct observation of a health-care provider.

<span class="mw-page-title-main">Oxymorphone</span> Opioid analgesic drug

Oxymorphone is a highly potent opioid analgesic indicated for treatment of severe pain. Pain relief after injection begins after about 5–10 minutes, after oral administration it begins after about 30 minutes, and lasts about 3–4 hours for immediate-release tablets and 12 hours for extended-release tablets. The elimination half-life of oxymorphone is much faster intravenously, and as such, the drug is most commonly used orally. Like oxycodone, which metabolizes to oxymorphone, oxymorphone has a high potential to be abused.

<span class="mw-page-title-main">Dipipanone</span> Opioid analgesic drug

Dipipanone, sold under the brand names of Pipadone and Diconal is a strong opioid analgesic drug, used for acute pain by mouth (PO) for adults. It is often used in instances where morphine is indicated but cannot be used due to the patient being allergic to morphine. In analgesic potency 25 mg dipipanone is approximately equivalent to 10 mg morphine.

<span class="mw-page-title-main">Levorphanol</span> Opioid analgesic drug

Levorphanol is an opioid medication used to treat moderate to severe pain. It is the levorotatory enantiomer of the compound racemorphan. Its dextrorotatory counterpart is dextrorphan.

Opioid-induced hyperalgesia (OIH) or opioid-induced abnormal pain sensitivity, also called paradoxical hyperalgesia, is an uncommon condition of generalized pain caused by the long-term use of high dosages of opioids such as morphine, oxycodone, and methadone. OIH is not necessarily confined to the original affected site. This means that if the person was originally taking opioids due to lower back pain, when OIH appears, the person may experience pain in the entire body, instead of just in the lower back. Over time, individuals taking opioids can also develop an increasing sensitivity to noxious stimuli, even evolving a painful response to previously non-noxious stimuli (allodynia). This means that if the person originally felt pain from twisting or from sitting too long, the person might now additionally experience pain from a light touch or from raindrops falling on the skin.

<span class="mw-page-title-main">Tapentadol</span> Opioid analgesic of benzenoid class

Tapentadol, brand names Nucynta among others, is a centrally acting opioid analgesic of the benzenoid class with a dual mode of action as an agonist of the μ-opioid receptor and as a norepinephrine reuptake inhibitor (NRI). Analgesia occurs within 32 minutes of oral administration, and lasts for 4–6 hours.

<span class="mw-page-title-main">Dezocine</span> Opioid analgesic

Dezocine, sold under the brand name Dalgan, is an atypical opioid analgesic which is used in the treatment of pain. It is used by intravenous infusion and intramuscular injection.

<span class="mw-page-title-main">Ciramadol</span> Opioid analgesic drug

Ciramadol (WY-15,705) is an opioid analgesic that was developed in the late 1970s and is related to phencyclidine, tramadol, tapentadol and venlafaxine. It is a mixed agonist-antagonist for the μ-opioid receptor with relatively low abuse potential and a ceiling on respiratory depression which makes it a relatively safe drug. It has a slightly higher potency and effectiveness as an analgesic than codeine, but is weaker than morphine. Other side effects include sedation and nausea but these are generally less severe than with other similar drugs.

<span class="mw-page-title-main">Propiram</span> Opioid analgesic drug

Propiram is a partial μ-opioid receptor agonist and weak μ antagonist analgesic from the ampromide family of drugs related to other drugs such as phenampromide and diampromide. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. Propiram reached Phase III clinical trials in the United States and Canada.

<span class="mw-page-title-main">Nefopam</span> Analgesic medication

Nefopam, sold under the brand name Acupan among others, is a centrally acting, non-opioid painkilling medication, that is primarily used to treat moderate to severe pain.

"Pain ladder", or analgesic ladder, was created by the World Health Organization (WHO) as a guideline for the use of drugs in the management of pain. Originally published in 1986 for the management of cancer pain, it is now widely used by medical professionals for the management of all types of pain.

<span class="mw-page-title-main">Opiate</span> Substance derived from opium

An opiate is an alkaloid substance derived from opium. It differs from the similar term opioid in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain. Opiates are alkaloid compounds naturally found in the opium poppy plant Papaver somniferum. The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine. Opiates have long been used for a variety of medical conditions, with evidence of opiate trade and use for pain relief as early as the eighth century AD. Most opiates are considered drugs with moderate to high abuse potential and are listed on various "Substance-Control Schedules" under the Uniform Controlled Substances Act of the United States of America.

Opioid rotation or opioid switching is the process of changing one opioid to another to improve pain control or reduce unwanted side effects. This technique was introduced in the 1990s to help manage severe chronic pain and improve the opioid response in cancer patients. In order to obtain adequate levels of pain relief, patients requiring chronic opioid therapy may require an increase in the original prescribed dose for a number of reasons, including increased pain or a worsening disease state. Over the course of long-term treatment, an increase in dosage cannot be continued indefinitely as unwanted side effects of treatment often become intolerable once a certain dose is reached, even though the pain may still not be properly managed. One strategy used to address this is to switch the patient between different opioid drugs over time, usually every few months. Opioid rotation requires strict monitoring in patients with ongoing levels of high opioid doses for extended periods of time, since long term opioid use can lead to a patient developing tolerance to the analgesic effects of the drug. Patients may also not respond to the first opioid prescribed to them at all, therefore needing to try another opioid to help manage their pain. A patient's specific response and sensitivity to opioids include many factors that include physiology, genetics and pharmacodynamic parameters, which together determine the amount of pain control and tolerance of a particular opioid.