Pharmacology of Opioids and Analgesics

Tobacco

• Psychoactive chemical: Nicotine; safer cigarettes are discussed.
• Health hazards and carcinogens: Tobacco and smoke affect nearly every body part (mouth, brain, stomach, reproductive system). Hundreds of harmful chemicals, including acetone, ammonia, and hexamine, are present. Cigarette tar, a sticky brown mass from condensed particles, contains carcinogens. Examples of carcinogens and poisonous substances include Benzo(a)pyrene, Nitrosamines, Urethane, Arsenic, and Hydrogen cyanide. Combined with other substances, carcinogens can cause cancer.
• Smokeless tobacco and e-cigarettes: Smokeless tobacco has warning labels and increases the risk of oral cancer and dental problems. The product contains carcinogens like nitrosamines, which cause leukoplakia. E-cigarettes and health concerns are also noted.

E-cigarettes

• Nicotine delivery system: E-cigarettes deliver nicotine and other chemicals in vapor form.

Long-Term Effects of Smoking

• Impact on organs: Smoking harms lungs, heart, blood vessels, and other organs.
• Leading cause of death: Smoking is the most preventable cause of death, with risk increasing more with earlier and longer exposure.
• Chronic bronchitis: Inflammation of the airways.
• Blood vessel damage: Nicotine damages blood vessels, leading to plaque buildup.
• Diabetic effect: Smoking can worsen diabetes by affecting insulin resistance.

Environmental Tobacco Smoke (ETS)

• Components: ETS contains mainstream smoke (exhaled by smoker), sidestream smoke (from burning end), and thirdhand smoke (residual chemicals on surfaces).
• Classification: Environmental tobacco smoke is a Class A carcinogen.
• Exposure effects: Exposure causes health problems in those around smokers and those who live in the environment of secondhand smokers.

Nicotine Pharmacology

• Absorption and metabolism: Nicotine is highly absorbed (90%) when inhaled, deactivated in the liver, and excreted by the kidneys.
• Tolerance: Nicotine use increases liver enzyme activity, contributing to tolerance and making a lethal dose possible.
• Half-life: Nicotine has a short half-life (24-84 minutes).
• Mechanism of action: Nicotine mimics acetylcholine, stimulating and then blocking receptors. It triggers a release of dopamine and adrenaline. It has an indirect sympathomimetic effect

Quitting Smoking

• Challenges: Quitting smoking is difficult due to physiological and behavioral effects.
• Treatments: Treatments such as replacement therapy (gum, patches, inhalers) and pharmacological therapy (bupropion) aid quitting attempts.

Caffeine

• Class of chemicals: Caffeine belongs to the xanthine class of chemicals.
• Sources: Caffeine is present in xanthines, including caffeine, theophylline, and theobromine. These chemicals are found in coffee, tea, and chocolate.
• Plant sources: These are derived from coffee plants, tea plants, and cacao plants.

Xanthine Content

• Coffee content: An average cup of coffee has 90-95 mg of caffeine.
• Tea content: Tea contains 40-60 mg of caffeine per cup, depending on the type and brew strength.
• Chocolate content: An average cup of cocoa contains 4 mg caffeine.
• Theophylline and theobromine: Theophylline is mainly found in tea, and used as an asthma medication. Theobromine is present in chocolate and is less potent than caffeine.

Caffeine Pharmacology

• CNS and cardiovascular effects: Caffeine is a stimulant. Theophylline and theobromine are the most potent cardiac stimulants; caffeine has less effect.
• Time course: Fast absorption, peak levels in 30 minutes, half-life about 3 hours (short duration of action)
• Withdrawal symptoms: Withdrawal symptoms include fatigue and headache.
• DSM-5: Caffeine is not officially listed as a substance use disorder in DSM-5.
• Mechanism of action: Xanthines block adenosine receptors in the brain, which also have a calming effect. A decrease in adenosine release results in stimulation
• Physiological effects: Caffeine and other xanthines stimulate the CNS, skeletal muscles, and can cause sleep disturbances and constrict blood vessels.
• Cognitive effects: Caffeine can partially counter the effects of fatigue, although it does not improve performance in well-rested individuals.

Opioids

• Naturally occurring substance: Derived from the opium poppy plant.
• Analgesic and anesthetic: Provides pain relief, pleasure, and anxiety relief.
• Mechanism of action: Bind to opioid receptors in the brain (mu, delta and kappa) affecting pain and emotional centers.
• Classification: Opioids are categorized as natural (morphine, codeine, thebaine), semi-synthetic (heroin, oxymorphone, hydromorphone) and synthetic (meperidine, methadone, morphinians, benzamorphans).
• Agonists & antagonists: Agonists activate receptors; antagonists block them.

Opioid Examples (Morphine, Codeine, Heroin, Fentanyl)

• Opiate & opioid action: Opiates are generally natural and the first connection to the plant. Opioids are a broad category of drugs with natural and synthetic members.
• Potency: Morphine is 10 times more potent than opium.
• Uses: Clinically useful strong analgesic, addictive potential.
• Codeine: Less analgesic strength than morphine, is an antitussive. High doses can cause respiration problems and death.
• Misconceptions: Withdrawing is typically described as excruciating-similar to a mild case of the intestinal flu; after one injection, dependence is not necessarily immediate.

Mechanism of Action on the Brain, Opioid Receptors, and Antagonists

• Brain mechanisms: Opioids and related compounds function by binding to receptors in the brain and glands (enkephalins & endorphins).
• Specific receptors & Neurotransmitters: Targeting mu, delta, and kappa opioid receptors. Interfering with GABA & norepinephrine receptors is a common target..

Acute and Chronic Opioid Toxicity and Misuse

• Acute toxicity: Opioids cause respiratory depression, and sometimes nausea and vomiting.
• Chronic toxicity: Injection and use leads to spread of blood-borne diseases.
• Tolerance: Higher doses needed to maintain effects.
• Physical dependence: withdrawal is unpleasant, but not life-threatening. Can be prevented with opioid agonists.
• Psychological dependence: Positive and negative reinforcement related to drug use. Psychological issues are often associated with overuse.
• Misconceptions: Withdrawal issues can range from mild to intense, requiring professional guidance. Dependence can occur quickly.

Psychedelics

• Alter perceptions and moods: Oldest known drugs that change how the brain perceives and acts.
• Medical uses: Used to treat mental health illnesses (LSD, psilocybin, MDMA).
• Chemical groups: Belong to indole chemical groups, with examples including LSD, psilocybin, and MDMA.
• Brain activity effects: Altered levels of serotonin play a significant role in how the brain works, creating synesthesia (sound perceived as colors etc) or confusion.
• Factors for classification Include chemical structure and pharmacological properties, comparing relative dangers, and how severe hallucinations or other effects are.

Phantastica and Deliriants

• Phantastica: Allow user to communicate with the present world while altering perceptions. LSD, psilocybin, mescaline, and MDMA are in this category.
• Deliriants: Lead to mental confusion and reality distortion. PCP and ketamine are examples of deliriants.

Mechanism of action(LSD, Psilocybin, Mescaline, MDMA)

• Physical Effects: Dilated pupils, increased body temperature, increased heart rate, and blood pressure.
• Psychological effects: Feelings of spiritual connection, terrifying thoughts and sensations (synesthesia, or crossing over of senses).
• Mechanism of action: Stimulates serotonin-21 receptors in the brain, impacting dopamine and norepinephrine receptors and other neurotransmitters, like glutamate.

Cannabis

• Derived from cannabis plants: Chemicals in cannabis plants can be used for medicinal substances. Marijuana is a type of processed preparation from leafy material of the plant.
• THC: A dominant chemical component in marijuana, causing psychoactive effects and is one of the reasons marijuana is considered a schedule 1 drug.
• Cannabinoids: A group of psychoactive ingredients.
• CBD: Does not create feelings of "high" but has various medicinal uses like relieving pain, being neuroprotective, and other applications.
• THC Pharmacology & time-course: Oral and smoked THC differ in absorption speed and duration of effects. THC is metabolized in the liver.
• Mechanism of action: THC binds to CB1 and CB2 receptors in the brain triggering anandamine production in the brain.

Medical Uses of Marijuana and Physiological Effects

• Effective medicine: Safe and effective medicine for various conditions including nausea and appetite stimulation..
• Physiological effects: Increased heart rate, reddened eyes, dryness, munchies (increased appetite), and elevated mood (euphoria). Duration of effects may vary with methods of consumption.

Abuse Potential and Dependence

• Different time course: Different methods of using THC have differing impact duration and effects.
• Tolerance: Repeated exposure can increase tolerance, leading to needing higher doses to experience a similar effect.
• Withdrawals: Withdrawals are typically not life-threatening but may be unpleasant and include anxiety and irritability. The duration can last from a day to 12 days.
• Acute/chronic effects: Increased heart rate , lung damage (impaired air flow), lower sperm counts in men and lower birth rates in women. Some associated risks for those with existing conditions like cardiovascular disease.

Test your knowledge on the pharmacology of opioids and their effects. This quiz covers the classification, mechanisms, and risks associated with opioid use, as well as related substances like xanthines. Perfect for students in pharmacology or healthcare fields!