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.
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]
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 ]
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]
![]() | This section appears to contradict the equianalgesic table in the article on oxycodone .(September 2023) |
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 ]
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 ]
Analgesic | Strength (relative) | Equivalent dose (10 mg oral morphine) [b] | Bioavailability | Half-life of active metabolites (hours) | Oral-to-parenteral ratio | Speed of onset | Duration | |
---|---|---|---|---|---|---|---|---|
Paracetamol (non-opioid) | 1⁄360 | 3600 mg | 63–89% | 1–4 | 37 min (PO); 8 min (IV) | 5–6 hours | ||
Aspirin (NSAID, non-opioid) | 1⁄360 | 3600 mg | 80–100% | 3.1–9 | ||||
Ibuprofen [10] (NSAID, non-opioid) | 1⁄222 | 2220 mg | 87–100% | 1.3–3 | ||||
Diflunisal (NSAID, non-opioid) | 1⁄160 | 1600 mg | 80–90% | 8–12 | ||||
Naproxen [10] (NSAID, non-opioid) | 1⁄138 | 1380 mg | 95% | 12–24 | ||||
Piroxicam (NSAID non-opioid) | 1⁄120 | |||||||
Indomethacin (NSAID non-opioid) | 1⁄64 | |||||||
Diclofenac [10] [11] (NSAID, non-opioid) | 1⁄10 | 100 mg (est.) | 50–60% | 1–4 | ||||
Ketorolac [12] (NSAID, non-opioid) | 1⁄3 | 30 mg IV (est.) | 80–100% | 5–7 | ||||
Nefopam (Centrally-acting non-opioid) | 5⁄8 | 16 mg IM (est.) | Nefopam: 3–8, Desmethylnefopam 10–15 | |||||
Dextropropoxyphene [13] | 1⁄20 | 130–200 mg | ||||||
Codeine | 3⁄20 | 100–120 mg (PO) | ~90% | 2.5–3 (C6G 1.94; [14] morphine 2–3) | 15–30 min (PO) | 4–6 hours | ||
Tramadol | 1⁄10 | ~100 mg | 75% (IR), 85–90% (ER) | 6.0–8.8 [15] (M1) | ||||
Opium (oral) | 1⁄10 | ~100 mg | ~25% (morphine) | 2.5–3.0 (morphine, codeine) | ||||
Tilidine | 1⁄10 | 100 mg | ||||||
Dihydrocodeine | 1⁄5 | 50 mg | 20% | 4 | ||||
Anileridine [16] | 1⁄4 | 40 mg | ||||||
Alphaprodine | 1⁄6 | 40–60 mg | ||||||
Tapentadol [17] | 3⁄10 | 32 mg | 32% (fasting) | |||||
Pethidine (meperidine) | 1⁄3 | 30 mg SC/IV/IM 300 mg (PO) | 50–60% Orally, 100% SC/IV/IM | 3–5 | 5–15 sec if IV, 15–25 min if orally | |||
Dipipanone [18] [19] | 2⁄5 | 25 mg (PO) | 3.2–3.8 hours | ±4 hours | ||||
Benzylfentanyl | 1⁄2 | |||||||
AH-7921 | 4⁄5 | |||||||
Hydrocodone | 1 | 10 mg | 70% [20] | 3.8–6 (Instant Release; PO) | 10–30 min (Instant Release; PO) | 4–6 | ||
Metopon | 1 | 10 mg | ||||||
Pentazocine lactate (IV) [21] | 1 | 10 mg SC/IV/IM, 150 mg (PO) | ||||||
SR-17018 | 4⁄5 | 10–12 mg | 100% IV (Presumably) Unknown (researches are still being made) | 5–10 seconds if used IV and 15-25 min Orally (PO) | ||||
Morphine (oral) | 1 | 10 mg | ~25% | 2–4 | 3:1 | 30 min (PO) | 3–6 hours | |
Oxycodone (oral) [22] | 1.5 | 6.67 mg | (60–87 / ±75% PO) / 78.2% [23] (IN) / 100% (IV/IM) or other parenteral administrations apart from spinal administration | 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) [24] | ||
Spiradoline | 1.5 | |||||||
Nicomorphine | 2–3 | 3.33–5 mg | 20% | 4 | ||||
Oxycodone (IV/IM) or other parental administrations apart from spinal administration [25] | 3–4 | 2.5–3.33 mg | (60–87 / ±75% PO) / 78.2% [23] (IN) / 100% (IV/IM) or other parental administrations apart from spinal administration | 1.5–3 (IV/IM) | 5 min (IV) [25] | 2–4 hours | ||
Morphine (IV/IM) or other parental administrations apart from spinal administration | 3–4 | 2.5–3.33 mg | 100% | 3–4 | 3:1/4:1 | Instantaneously (from 5 to 15 sec; IV); 5–15 min (IM) | 3–7 hours | |
Clonitazene | 3 | 3.33 mg | ||||||
Methadone (acute) [26] [27] | 3–4 | 2.5–3.33 mg | 40–90% | 15–60 | 2:1 | |||
Methadone (chronic) [27] | 2.5–5 | 2–4 mg | 40–90% | 15–60 | 2:1 | |||
Phenazocine | 4 | ~2.5 mg | ||||||
Diamorphine (Heroin; IV/IM) or other parental administrations apart from spinal administration [28] | 4–5 (IV,IM) 2–2.5 (insufflated) [29] | 2–2.5 mg | 100% | <0.6 (morphine prodrug) [30] | Instantaneously (from 5 to 15 sec; IV); 2 to 5 min (IM) | 3 to 7 hours | ||
Dezocine | 4–6 | 1.6–2.5 mg | 97% (IM) | 2.2 | ||||
6-MAM [31] | 6–7 | 1.25–1.6 | 100% (IV,IM) | <0.6 (morphine prodrug) [30] | presumably 2:1 | Instantaneously (from 5 to 15 sec; IV); 2 to 5 min (IM) | 3 to 7 hours | |
Hydromorphone [32] [33] [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% | 2–3 | 5:1 | |||
Oxymorphone [22] | 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% | 7.25–9.43 | 35 min (PO), Instantaneously (from 5 to 15 sec)(IV) | 6–8 hours orally 2–6 hours parenteral | ||
U-47700 | 7.5 | 1.5 mg | 1.5–3 | |||||
Levorphanol [34] | 8 | 1.25 mg | 70% | 11–16 | 1:1 | |||
Desomorphine | 8–10 | 1–1.25 mg | ~100% (IV) | 2–3 | Instantaneously (from 5 to 15 sec)(IV); 2–5 min (IM) | 3–4 hours | ||
N-Phenethylnormorphine | 8–14 | |||||||
Alfentanyl | 10–25 | 1.5 (90–111 minutes) | Instantaneously (from 5 to 15 sec); 4× more rapid than fentanyl | 0.25 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 | 25 | 15 μg (threshold) and 0.160 mg/kg (dissociative effects) | ||||||
Buprenorphine (SL) [13] | 40 | 0.25 mg | 30% (SL); [35] ~100% (TD); 65% (buccal); [36] [37] 48% (INS) [38] | 20–70, mean 37 | 3:1 | 45 min | 12–24 hours | |
N-Phenethyl-14-ethoxymetopon | 60 | 160 μg | ||||||
Phenomorphan | 60–80 | 0.13–0.16 mg | ||||||
N-Phenethylnordesomorphine | 85 | |||||||
Phenaridine | 50-100 | |||||||
Fentanyl | 50–100 | 0.1 mg (100 μg) IM/IV | 33% (SL); 92% (TD); 89% (INS); 50% (buc) | 0.04 (IV); 7 (TD) | 5 min (TD/IV) | 30–60 minutes (IV) | ||
Metonitazene | 100 | 0.1 mg/100 μg | ||||||
Acrylfentanyl | 50-100+ | |||||||
Buprenorphine (Transdermal) [39] [40] | 100–115 | 0.1 mg (100 μg) | 30% (SL); [35] ~100% (TD); 65% (buccal); [36] [37] 48% (INS) [38] | 3:1 | 45–60 minutes | 12–24 hours | ||
14-Cinnamoyloxycodeinone | 177 | 77 μg | ||||||
Etonitazepyne | 180-190 | 55–60 μg | ||||||
Protonitazepyne | 180-190 | 55–60 μg | ||||||
Remifentanil | 100–200 | 50–100 μg | 0.05 (3–6 min context-sensitive half-life; 7–18 min elimination half-life) | Instantaneously (from 5 to 15 sec) | 15 minutes; rapid offset of effects necessitates continuous infusion for maintenance of anesthesia | |||
Protonitazene | 200 | 50 μg | ||||||
Ocfentanil | 125–250 | 40–80 μg | ||||||
Ro4-1539 | 240–480 | 20–40 μg | ||||||
Isotonitazene | 500 | 20 μg | ||||||
Sufentanil | 500–1,000 | 10–20 μg | 4.4 | |||||
BDPC | 504 | ~20 μg | ||||||
C-8813 | 591 | |||||||
4-Phenylfentanyl | 800 | |||||||
Etonitazene | 1000–1500 | 6.6–10 μg | ||||||
3-Methylfentanyl | 1000–1500 | |||||||
N-Desetylisotonitazene | 1000–2000 | 5–10 μg | ||||||
Etorphine | 1,000–3,000 | 3.3–10 μg | ||||||
Ohmefentanyl | 6300 | |||||||
Acetorphine | 8700 | 1.33 μg | ||||||
Dihydroetorphine [41] | 1,000–12,000 | 0.83–10 μg (20–40 μg SL) | ||||||
Carfentanil [42] | 10,000 | 1.0 μg | 7.7 | |||||
2-Fluorohmefentanil | 18,000 | |||||||
4-Carboethoxyohmefentanil | 30,000 | |||||||
Ohmecarfentanil | 30,000 | |||||||
R-30490 | 10,000-100,000 | |||||||
Lofentanil | 10,000-100,000 | |||||||
14-Methoxymetopon (intraspinally) [43] | 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. |
An analgesic drug, also called simply an analgesic, antalgic, 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.
Hydrocodone, also known as dihydrocodeinone, is a semi-synthetic 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 sold 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, it is classified as a Schedule II Controlled Substance.
Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as an analgesic. There are numerous methods used to administer morphine: orally; administered under the tongue; via inhalation; injection into a vein, injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via administered into the rectal canal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are sold under the brand names MS Contin and Kadian, among others. Generic long-acting formulations are also available.
Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid used medically to treat chronic pain and opioid use disorder. Prescribed for daily use, the medicine relieves cravings and opioid 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.
Oxycodone, sold under the brand name Roxicodone and OxyContin among others, is a semi-synthetic opioid used medically for the treatment of moderate to severe pain. It is highly addictive and is a commonly abused drug. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.
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).
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.
Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, including pain relief.
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.
Dihydrocodeine is a semi-synthetic opioid analgesic prescribed for pain or severe dyspnea, or as an antitussive, either alone or compounded with paracetamol (acetaminophen) or aspirin. It was developed in Germany in 1908 and first marketed in 1911.
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.
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.
The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(mu)-opioid peptide (MOP) receptors. The prototypical μ-opioid receptor agonist is morphine, the primary psychoactive alkaloid in opium and for which the receptor was named, with mu being the first letter of Morpheus, the compound's namesake in the original Greek. It is an inhibitory G-protein coupled receptor that activates the Gi alpha subunit, inhibiting adenylate cyclase activity, lowering cAMP levels.
Tapentadol, sold under the brand names Nucynta and Palexia among others, is a synthetic opioid analgesic of the benzenoid class with a dual mode of action as a highly selective full agonist of the μ-opioid receptor and as a norepinephrine reuptake inhibitor (NRI). Tapentadol is used medically for the treatment of moderate to severe pain. It is addictive, a commonly abused drug, and poses a high risk of physical and/or mental dependence.
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.
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.
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.
Nefopam, sold under the brand name Acupan among others, is a centrally acting, non-opioid painkilling medication, with central stimulant and sympathomimetic properties 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.
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.
Explanatory notes
Citations
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.
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). ...
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