How do opioid analgesics work?
Opioidanalgesics are medications prescribed for the management ofacuteandchronic paininmany conditions. Opioid analgesics are also used to treat opioid use disorder. Opioid medications have a high risk foraddictionand must be used with great caution.
All opioid analgesics bind to opioid receptors but work in different ways. Opioid receptors areproteinmolecules onnerve cell(neuron) membranes in thecentralandperipheralnervous systems. Opioid receptors mediate the body’s response to most hormones and some of their functions include modulatingpain,stressresponse,respiration, digestion, mood, and emotion.
The five different opioid receptors discovered in the human body are:
- Mureceptor(MOR)
- Kappa receptor (KOR)
- Delta receptor (DOR)
- Nociceptin receptor (NOR)
- Zeta receptor (ZOR)
Opioid analgesics work by binding to one or more of the opioid receptors. Opioid analgesics are primarily of three types:
- Opioid agonists: Full opioid agonists relieve pain by stimulating opioid receptors on neurons, which inhibit the release of chemicals (neurotransmitters) that transmit pain signals.
- Partial opioid agonists: Partial opioid agonists elicit a partial functional response because they work as agonists in some receptors and antagonists in others, and consequently, produce fewer adverse effects than full agonists while being effective for pain relief (analgesia).
- Opioid antagonists: Opioid antagonists bind to opioid receptors but do not produce any functional response. Opioid antagonists prevent agonists from binding to the particular opioid receptor and are useful in treating opioid dependence.
How are opioid analgesics used?
Opioid analgesics come in many formulations and strengths. Opioid analgesics are administered through several routes such as:
- Oral: Tablets, capsules, syrups, solutions, lozenges
- Rectal: Suppositories
- Ureteral: Suppositories
- Transmucosal:
- Nasal: Sprayed into thenostril
- Injections:
- Subcutaneous:注入tissue under theskin
- Long-acting subcutaneous injection: Monthly injection into the tissue under the skin
- Intramuscular:注入肌肉
- Intravenous:注入vein
- Epidural:注入space outside the uppermost layer (dura) of the spinal canal
- Intrathecal: Injected into thecerebrospinal fluidin the spinal canal
- Subdermal:Implantplaced under the skin on the inner side of the upperarm, for slow release ofmedicationthat lasts up to six months
- Transdermal: Applied as a skin patch that slowly releases medication over 7 days, and is absorbed through the skin
Opioid analgesics are used to manage severe pain when alternative treatments are inadequate, and to treat opioid use disorder. Some opioid analgesics are used to treatdiarrheabecause they inhibitstomachacid secretion andgastrointestinalpropulsion and motility. Opioid analgesics should be used with caution in patients withkidneyorliverimpairment.
Opioid overdose can have severe consequences, andnaloxone, an opioidantagonist, is administered to reverse opioid effects in case of opioid overdose. Opioid analgesics are typically never abruptly discontinued, but tapered with an opioidagonist/antagonist combination before weaning off.
Opioid analgesics may be used in conditions that include:
- Severeacute pain
- Moderate to severe pain
- Severechronicpain
- Breakthrough pain in conditions such ascancer, sickle-celldisease
- Diabeticperipheral neuropathy
- HIV-associatedneuropathy
- Postherpetic neuralgia
- Laborpain
- Preoperativeand preanesthesia
- Balancedanesthesia
- General and local anesthesia
- Adjunct anesthesia
- Conscious analgesia
- Continuous sedation and analgesia
- Post-operative analgesia
- CyanoticTetralogy of Fallot(congenitalheartdefects that lead to lowoxygenand bluishskin colorin premature newborns)
- Weaning off from full opioid agonists
- Opioid addiction and dependence (opioid use disorder)
- Diarrhea
- Chroniclow back pain
- Opioid-inducedpruritus(itching), off-label
- Cough(off-label)
What are side effects of opioid analgesics?
Side effects of opioid analgesics may include the following:
- Dizziness
- Somnolence(drowsiness)
- Lightheadedness
- Headache
- Malaise
- Fatigue
- Asthenia(weakness)
- Fever
- Constipation
- Nausea
- Vomiting
- Belchingand retching
- Anorexia(loss of appetite)
- Abdominal pain
- Abdominaldistention
- Dyspepsia(indigestion)
- Diarrhea
- Reduced intestinal motility
- Paralytic ileus(paralysisof intestinal muscles)
- Gastroesophageal refluxdisease (GERD)
- Gastritis
- Gastroenteritis
- Gastrointestinal bleeding
- Biliarytractspasm
- 打嗝
- 肠胃气胀
- Skin reactions such as:
- Rash
- Blisters
- Urticaria(hives)
- Pruritus (itching)
- Dermatitis
- Stevens-Johnson syndrome(a rare medical emergency withflu-like symptoms and a painful rash)
- Toxicepidermalnecrolysis (a severe skinconditionwith widespread redness, skin celldeath, and exfoliation which can lead tosepsis)
- Hypersensitivity reactions such as:
- Angioedema(swelling in the tissue under the skin ormucousmembranes)
- Oropharyngealedema(swelling in themouth, tongue, andpharynx)
- Back pain
- Arthralgia(jointpain)
- Arthritis(inflammationof joints)
- Myalgia(muscle pain)
- Influenza
- Chills
- Neck pain
- Pelvic pain
- Burning at the injection site
- Application site reaction with skin patches
- Infection
- Abscess
- Hyperhidrosis(excessivesweating)
- Flushing
- Hot flashes
- Dehydration
- Pallor
- Blurred vision
- Amblyopia(lazy eye)
- Runny eyes
- Miosis(pupilconstriction)
- Mydriasis(pupildilation)
- Visual disturbances
- Cataracts
- Conjunctivitis(eyeinflammation)
- Tinnitus(ringing in the ears)
- Earpain
- Dysgeusia(tastedistortion)
- Glossitis(tongue inflammation)
- Stomatitis (soremouth)
- Xerostomia(dry mouth)
- Nasalcongestion
- Nasal irritation
- Rhinorrhea(runny nose)
- Epistaxis(nasal bleeding)
- Sinuscongestion
- Histaminerelease
- 粘膜炎症
- Rhinitis(inflammation ofnasal passage)
- Sinusitis(inflammation of the sinuses)
- Pharyngitis(inflammation of the pharynx)
- Bronchitis(inflammation of the bronchial passage)
- Central nervous system(CNS)depression
- Paradoxical CNS stimulation
- Agitation
- Confusion and mental fog
- Difficulty in concentration
- Falsesenseof well-being
- Floating feeling
- Mood swing
- Restlessness
- Euphoria
- 烦躁不安(不安)
- Anxiety
- Depression
- Depersonalization
- Insomnia
- Abnormaldreams
- Abnormal thinking
- Hallucination
- Delirium
- Paranoid reaction
- Suicidaltendency
- Psychosis
- Amnesia(memoryloss)
- Tremor
- Speech disorder
- Paresthesia(pricklingsensation)
- Hyperalgesia (heightenedsensitivityto pain)
- Myoclonus(involuntarytwitchingor jerking of muscles)
- Muscle spasms
- Hypertonia(excessive muscle tone)
- Skeletal musclerigidity
- Abnormal coordination andgait
- Accidentalinjury
- Seizures
- Sedation
- Coma
- Intracranialpressure
- Upperrespiratorytract infection
- Cough
- Pneumonia
- Atelectasis(partial or complete collapse of a lung orsectionof a lung)
- Hemoptysis(coughing up blood)
- Dyspnea(shortness of breath)
- Apnea(cessation of breath)
- Respiratory depression(hypoventilation/shallowbreathing)
- Respiratory arrest
- Bronchospasm
- Asthma
- Pulmonary edema
- Pulmonary embolism
- Hypoxia(low oxygen saturation in tissues)
- Angina pectoris(chest pain)
- Hypertension(high blood pressure)
- Myocardial infarction(heart attack)
- Tachycardia(rapid heartbeat)
- Palpitations
- Arrhythmia(irregular heartbeat)
- AbnormalECGresults such as:
- QT-interval prolongation
- ST-segment elevation
- Shock
- Cardiacarrest
- Circulatorydepression
- Wenckebach block (atrioventricularnodal block)
- Vasodilation
- Bradycardia(slow heartbeat)
- Hypotension(low blood pressure)
- Orthostatic hypotension(blood pressuredrop when standing up from sitting or lying down)
- Vertigo
- Syncope(fainting)
- Adrenal insufficiency
- Micturitiondisorder (abnormality in urination)
- Ureteral spasm
- Oliguria(decreased urination)
- Dysuria(painful urination)
- Urinaryretention
- Urinary tract infection(UTI)
- Cystitis(bladder inflammation)
- Creatinineincrease
- Proteinuria(excessive protein in theurine)
- Kidney failure
- Prostatic disorder
- Peripheral edema
- Oropharyngeal edema (swelling in the mouth, tongue, and pharynx)
- Abnormal liver function test results
- Elevated liverenzymessuch as GGT,SGPT
- Elevatedblood urea nitrogen(BUN) levels
- Hepatitis
- Liver failure
- Gout
- Hyperglycemia(highglucosein theblood)
- Anemia
- Lowhemoglobin
- Ecchymosis(skin discoloration due to bleeding under the skin)
- Weight loss
- Serotoninsyndrome
- Menstrualdisorder
- Menopausal symptoms
- Androgendeficiency
- Erectile dysfunction
- Neonatalopioid withdrawal syndrome
- Physical and psychological opioid dependence
- Congenital oculomotor (eye muscle movement) disorders frommethadoneuse duringpregnancy
- Death related to ultra-rapid metabolizers ofcodeine
Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with yourdoctoror药剂师为了确保这些药物时不造成任何伤害n you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.
What are names of some opioid analgesic drugs?
Genericand brand names of some opioidanalgesicdrugs include:
- Actiq
- Buprenex
- buprenorphine
- buprenorphine transdermal
- butorphanol
- Butrans
- codeine
- ConZip
- Demerol
- Dilaudid
- Dilaudid-HP
- Dsuvia
- Duragesic
- Duramorph
- fentanyl
- fentanyl intranasal
- fentanyl transdermal
- fentanyl transmucosal
- Fentora
- hydrocodone
- hydromorphone
- Hysingla ER
- Infumorph
- Kadian
- Lazanda
- levorphanol
- loxicodegol (pendingFDAapproval)
- meperidine
- methadone
- Methadose
- Mitigo
- morphine
- MS Contin
- nalbuphine
- Nucynta
- Nucynta ER
- oliceridine
- Olinvyk
- Oxaydo
- oxycodone
- OxyContin
- oxymorphone
- paregoric
- Qdolo
- remifentanil
- Roxicodone
- Sublimaze
- Subsys
- Sufenta
- sufentanil
- sufentanil SL
- tapentadol
- tramadol
- Ultiva
- Ultram
- Xtampza ER
- Zohydro ER