MD216 | CNS stimulants & drug abuse

What is the mechanism of action of doxapram?

respiratory stimulant

Which patients should avoid doxapram?

Kidney & Liver disease patients

Indication of doxapram

Sedative overdose, Post-anesthetic, Idiopathic hypoventilation

What drug is used in idiopathic hypoventilation?

Doxapram

Mechanism of action of picrotoxin

inhibits GABA-A receptor 》decrease Cl influx 》Hyperexcitability

low dose Doxapram

activate carotid chemoreceptor

high dose Doxapram

activate medullary respiratory center

side effects of Doxapram

pulmonary hypertension & systemic vasoconstriction

GABA-A receptor blocker

Picrotoxin, Pentylenetetrazol

Mechanism of action of strychnine

inhibits glycine receptor 》 decrease Cl influx 》 hyperexcitability 》 increase skeletal muscle contraction 》severe injury 》rhabdomyolysis 》Acute kidney failure

Strychnine causes what?

Opisthotonus

Treatment for opisthotonus

Diazepam , Vecuronium

GABA-A receptor blocker cause what?

Tonic-clonic seizure

What receptors are inhibited by Amphetamine?

VMAT2 & Catecholamines transporter

Side effects of amphetamine

Euphoria, angina ,weight loss , Schizophrenia, hyperthermia

How Amphetamine act on the respiratory center

activate respiratory center 》 increase respiratory rate

BP after using amphetamine

Increase

Therapeutic uses of Dextroamphetamine & Methylphenidate

Narcolepsy & ADHD

Therapeutic uses of dexmethylphenidate

ADHD

Drug interactions of Amphetamine

1. Tricyclic antidepressants 》addictive effects

2. Antihypertensive drug 》 decrease action of the drugs

3. Tyramine 》 Hypertensive crisis " Cheese effect"

Cocaine inhibits

catecholamine transporter

Effect of cocaine

1. Local vasoconstriction

2. Block K+ channel 》arrhythmia

3. Local anesthetic

Side effects of cocaine

Arrhythmia, MI, cerebral vasoconstriction

Chronic use 》 anxiety, depression, psychosis

withdrawal syndrome of cocaine

dysphoria, cocaine craving

cocaine + alcohol

cocaethylene 》 cardiac arrest

Methylxanthine

1. Caffeine

2. Theophylline

3. Theobromine

MOA of methylxanthines

inhibits adenosine receptor 》 increase neurotransmitter release

methylxanthine > 1000 mg

delirium, seizure

Opioids

1. Morphine

2. Heroine

3. Codeine

MOA of opioids

1. Mu receptor agonist 》increase DA》Euphoria

2. K receptor agonist 》 Dysphoria

withdrawal syndrome of morphine & heroine

1. N/V

2. muscle aches

3. rhinorrhea

4. mydriasis

5. piloerection

6. sweating

treatment for withdrawal syndrome of morphine & heroin

1. Naloxone

2. Naltrexone

3. Methadone

active form of Marijuana

tetrahydrocannabinol (THC)

MOA of THC

binds CB1 》inhibits GABA interneuron in VTA 》increase DA》Euphoria

increase appetite

decrease IOP

relief chronic pain

Withdrawal syndrome of Marijuana

1. restlessness

2. insomnia

3. irritability

Effect of gamma-hydroxybutyric acid (GHB)

1. Euphoria

2. increase sensory

3. amnesia

Hallucinogens

Lysergic acid diethylamide (LSD)

symptoms after using LSD

perceptual symptoms : shape & color distortion

❌️dependence

MOA of nicotine

stimulates nicotinic Ach receptors in the mesolimbic pathway 》 addiction

withdrawal syndrome of nicotine

irritability, sleep problem

treatment for withdrawal syndrome of nicotine

1. slowly absorbed form of nicotine

2. Bupropion

MOA of benzodiazepines

acts on alpha1- GABA-A receptor 》 Euphoria

withdrawal syndrome of benzodiazepines

irritability, insomnia, phonophobia

MOA of alcohol

1. stimulates GABA-A receptor

2. stimulates glycine receptor

3. stimulates 5-HT3 receptor

4. inhibits NMDA receptor

withdrawal syndrome of alcohol

tremor , sweating, agitation

MOA of ketamine& phencyclidine

inhibits NMDA receptor 》decrease memory function & vision

❌️ ADDICTION & WITHDRAWAL SYNDROME

Ecstasy

Methylenedioxymethamphetamine (MDMA)

MOA of MDMA

binds to 5HT transporter (SERT)》 acute toxic effect : Hyperthermia

Withdrawal syndrome of amphetamine

Dysphoria

Withdrawal syndrome of MDMA

depression