Neurons and Neurotransmitters

• Neurotransmitters are chemical messengers carrying signals across synapses.
• GABA is an inhibitory neurotransmitter that stabilizes the brain by decreasing neural transmission, preventing over-excitation.
• Norepinephrine is an excitatory neurotransmitter involved in wakefulness and alertness.
• A neuron consists of four basic parts: soma, dendrites, axon, and terminal buttons.
• The soma, or cell body, contains the nucleus, mitochondria, and cytoplasm, all enclosed by a membrane.
• Dendrites are neuron branches that receive messages from other neurons via molecular receptors.
• The axon is a slender tube carrying messages from the soma to terminal buttons.
• Terminal buttons contain vesicles holding neurotransmitters, which are delivered across a synapse to other neurons.
• Common drug administration routes: orally, subcutaneously, intramuscularly, intradermally, intranasally, inhalational, sublingually, transdermally, and intravenously.
• Transdermal administration differs from oral in how fast it acts and in patient compliance.
• A small therapeutic index indicates a less safe drug, often requiring blood level monitoring.
• Pharmacokinetics involves four stages after administration: absorption, distribution, metabolism, and elimination.
• The liver is the primary organ responsible for breaking down drugs into active metabolites.
• CYP450 enzymes in the liver are key in drug metabolism.

Anxiety and Psychosis

• Atypical antipsychotics are the recommended starting point for treating psychotic behaviors.
• Alcohol and benzodiazepines act as agonists to the GABA neurotransmitter.
• Dopamine is the primary neurotransmitter target for medications that treat psychosis.
• Beta-blockers, used for anxiety, are antagonists that block activating neurotransmitters like norepinephrine and adrenaline, slowing heart rate.

Depression and Bipolar Disorder

• SSRIs target serotonin, while SNRIs target norepinephrine and serotonin.
• GI side effects are common with antidepressants due to many serotonin receptors being located in the gut.
• Lithium is not metabolized in the liver and is excreted unchanged by the kidneys; dehydration can lead to toxicity due to increased reabsorption.
• TCAs, older antidepressants, affect many different systems and are not considered "clean" medications.
• Medications starting with "B" used to treat anxiety disorders: benzodiazepines, beta-blockers, barbiturates, and buspirone.
• Bioavailability refers to how much of a drug is available for use after pharmacokinetics.
• Bioequivalence measures the comparative efficacy of different drugs.
• Medications have different timelines for withdrawal symptoms due to varying half-lives.
• Bipolar disorder originates endogenously, but exogenous or psychosocial stressors can trigger or worsen cycles.

Antipsychotic EPS Effects, and Panic Disorder stages

• Four common EPS effects of antipsychotics: acute dystonia, parkinsonism, akathisia, and tardive dyskinesia.
• Acute dystonia involves intermittent or sustained muscle spasms of the trunk, head, and neck.
• Parkinsonism includes rigidity, bradykinesia, shuffling gait, and tremor.
• Akathisia presents clinically as feelings of inner restlessness and the inability to sit still.
• Tardive dyskinesia may include abnormal movements like lip smacking, facial grimacing, and tremors.
• Panic disorder treatment stages: stopping panic, regulating the limbic system with drugs that increase serotonin, and providing psychotherapy to reduce anticipatory anxiety.