Products
Analgesics are available in numerous dosage forms. These include, for example, tablets, effervescent tablets, powders, granules, suppositories, syrups, transdermal patches, and injectables. One of the oldest painkillers is opium, which is obtained from the incised, immature capsules of the opium poppy. It has been used medicinally for thousands of years. The first synthetic analgesics, such as salicylic acid, acetylsalicylic acid (aspirin), and acetanilide, a precursor to acetaminophen, were developed in the 19th century.
Structure and properties
Analgesics do not have a uniform chemical structure. However, several groups can be identified (see below).
Effects
Analgesics have analgesic (pain-relieving) properties. Some representatives are additionally antipyretic (antipyretic) and anti-inflammatory (antiphlogistic). Both peripheral and central drug targets exist. These include cyclooxygenases and opioid receptors.
Pharmacokinetics
Indications
For the treatment of acute and chronic pain. Some representatives are also used for the treatment of fever.
Dosage
According to the product information. Use depends on the individual product. Duration of therapy should be kept short if possible due to adverse effects.
Abuse
Opioids are abused as intoxicants because of their psychtropic, euphoric, and sedative properties. Typical examples include heroin, morphine, codeine, and oxycodone. Because of the high potential for dependence and the life-threatening and destructive adverse effects, abuse is strongly discouraged.
Active Substances
The following is a selection of important representatives: Acetanilides:
- Paracetamol
NSAIDs (non-steroidal anti-inflammatory drugs):
- Acetylsalicylic acid
- COX-2 inhibitor
- Diclofenac
- Ibuprofen
- Mefenamic acid
- Naproxen
Opioids:
- Codeine
- Fentanyl
- Hydromorphone
- Methadone
- Morphine
- Oxycodone
Pyrazolone:
- Metamizole
Other drug groups: Phytopharmaceuticals:
- Willow bark
Co-analgesics:
- Antiepileptic drugs
- Antidepressants
Cannabinoids:
- Dronabinol (THC)
- Cannabis
Anesthetics:
- Methoxyflurane
N-type calcium antagonists:
- Ziconotide
Piprante:
- Grapiprant (only as a veterinary drug).
Placebos have also shown some efficacy in clinical trials. Local anesthetics and anesthetics are not usually counted as analgesics.
Contraindications
Numerous precautions must be observed when using analgesics. Full details can be found in the drug label.
Adverse effects
Analgesics should not be consumed uncritically because of their potential adverse effects. Paracetamol is considered well tolerated but must be properly dosed because overdose damages the liver and is life-threatening. The most common potential adverse effects of NSAIDs include digestive upset and central nervous disturbances. All NSAIDs can rarely cause serious to life-threatening side effects, especially when taken over a long period of time. Common side effects of opioids at therapeutic doses include constipation, nausea, and fatigue. Overdose is life-threatening. Metamizole may rarely cause blood count disorders such as agranulocytosis.
