Chapter 7

Drug Classification and Indication, Nervous System and Functions

Nervous System Divisions:

  • Central Nervous System (CNS) and Peripheral Nervous System (PNS).

Functions:

  • Autonomic Nervous System: Manages involuntary motor activity.

  • Somatic Nervous System: Manages voluntary motor activities.

Neuron Structure:

  • Comprises body, axon, axon terminals, and dendrites.

Drug Classifications:

Seizure Disorders:

  • Epilepsy: Recurring seizures due to neuronal electrical disturbances.

    • Seizure Types: Focal and generalized.

    • Drug Therapy: Aims to eliminate seizures while maintaining quality of life.

    • Anticonvulsants: Narrow therapeutic ranges; brand-name specifications are common.

Parkinson’s Disease (PD):

  • Neurotransmitter imbalance (dopamine and acetylcholine).

    • Levodopa / Carbidopa: First-line treatment.

    • Dopamine Agonists: Eg. Bromocriptine.

    • MAOIs: Eg. Selegiline.

Multiple Sclerosis (MS):

  • Autoimmune disease affecting myelin.

    • Drug Treatments: Include beta interferons and Glatiramer acetate.

Alzheimer’s Disease:

  • Progressive dementia; Memantine may slow progression.

Attention Deficit Hyperactivity Disorder (ADHD):

  • Characterized by inattention and hyperactivity.

    • CNS Stimulant

The central nervous system (CNS) primarily utilizes a range of neurotransmitters, including seven key ones:

  1. Acetylcholine (ACh):

    • Function: Involved in motor control and also plays a role in arousal, attention, memory, and motivation.

    • System: Parasympathetic system.

  2. Norepinephrine (NE):

    • Function: Influences sleep, wakefulness, and mood; involved in the body's stress response.

    • System: Sympathetic system.

  3. Dopamine (DA):

    • Function: Plays roles in reward, motivation, memory, attention, and regulation of body movements.

    • System: Neither exclusively sympathetic nor parasympathetic but is involved in multiple CNS pathways.

  4. Serotonin (5-HT):

    • Function: Regulates mood, emotion, sleep, and appetite.

    • System: Neither exclusively sympathetic nor parasympathetic but influences both systems.

  5. Gamma-Aminobutyric Acid (GABA):

    • Function: Primary inhibitory neurotransmitter; plays a role in reducing neuronal excitability throughout the nervous system.

    • System: Neither exclusively sympathetic nor parasympathetic.

  6. Glutamate:

    • Function: Main excitatory neurotransmitter involved in cognitive functions such as learning and memory.

    • System: Neither exclusively sympathetic nor parasympathetic.

  7. Endorphins:

    • Function: Act as natural painkillers and are involved in pleasure and reward mechanisms.

    • System: Neither exclusively sympathetic nor parasympathetic but play roles in stress and pain response.

These neurotransmitters are integral to the functioning of the CNS, impacting various physiological responses and behaviors.