Pharmacology of Autonomic Nervous System, Neurological Disorders, and Antiepileptic Drugs

What is the primary purpose of the ANS and its main branches?

The ANS regulates internal functioning and maintains homeostasis, divided into the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS).

What basic terminology is essential for understanding ANS pharmacology?

Agonist: works along with; Antagonist: works against; Mimetic: to mimic; Lytic: to work against.

What intracellular events occur during ANS receptor stimulation?

Signal transduction involves action potentials from sodium and calcium influx, triggering neurotransmitter release.

What are the subtypes and functions of SNS receptors?

Alpha 1: vasoconstriction, pupil dilation, bladder sphincter constriction; Alpha 2: prevents overstimulation; Beta 1: increases heart activity and renin release; Beta 2: bronchodilation and uterine relaxation; Dopaminergic: improves renal perfusion.

What is the prototype adrenergic drug and its primary use?

Epinephrine (Adrenalin) is non-selective, used for Anaphylactic Shock, causing vasoconstriction, increased cardiac output, and bronchodilation.

How do vasopressors manage hypotension and shock?

Vasopressors like Levophed, Dopamine, and Dobutamine increase tissue perfusion; Dopamine is dose-dependent.

What are the characteristics of Adrenergic Blockers?

Alpha Blockers treat hypertension and BPH; Beta Blockers can be selective (Beta 1) or nonselective (Beta 1 & 2).

What are the physiologic effects and receptors of the PNS?

Acetylcholine is the primary neurotransmitter; Muscarinic receptors constrict pupils and decrease heart rate; Nicotinic receptors trigger muscle contractions.

What are the prototypes for Cholinergic and Anticholinergic drugs?

Cholinergic Agonist: Bethanechol treats urinary retention; Anticholinergic: Atropine blocks PNS effects.

What defines a 'Cholinergic Crisis'?

Toxicity from excessive Acetylcholine, characterized by SLUD: Salivation, Lacrimation, Urination, and Defecation.

How are Myasthenia Gravis and Alzheimer's Disease managed?

Myasthenia Gravis is treated with Neostigmine or Pyridostigmine; Alzheimer's is managed with reversible cholinesterase inhibitors.

What is the pathophysiology and treatment for Parkinson's Disease?

PD is a depletion of dopamine and excess acetylcholine; treated with Levodopa-Carbidopa and COMT Inhibitors.

How do AEDs work, and what are the primary prototypes?

AEDs decrease sodium influx, inhibit calcium influx, or increase GABA; prototypes include Phenytoin, Carbamazepine, Ethosuximide, and Valproic Acid.

What are the considerations for seizures during pregnancy?

Most AEDs are harmful to the fetus; Valproic Acid must be avoided due to spina bifida risk.

What is the first-line treatment for Status Epilepticus?

IV Benzodiazepines (Lorazepam or Diazepam), followed by Phenytoin.

What are the indications and risks for Neuromuscular Blockers?

Neuromuscular Blockers are used for muscle relaxation during surgery but carry risks of respiratory paralysis and prolonged effects.

What are the indications for Neuromuscular Blockers?

Used for intubation, ventilation, and surgery.

What are the risks associated with Neuromuscular Blockers?

They do not affect consciousness or pain; the patient is paralyzed but awake unless sedated. Nursing must assess for apnea and hyperkalemia.

What is the chronotropic effect?

Causing a change in heart rate.

What is the dromotropic effect?

Causing a change in speed of electrical conduction in the AV node of the heart.

What is the inotropic effect?

Causing a change in myocardial contraction.

What does normotensive mean?

Having normal blood pressure.

What is a pressor effect?

An effect that increases blood pressure.

What is affinity in pharmacology?

The rate of binding of ligands that demonstrates a tendency or strength of the effect.

What is an agonist?

A ligand that can bind to a receptor, alter the function of the receptor, and trigger a physiologic response.

What is an antagonist?

A ligand that binds to a receptor but fails to activate the physiologic response.

What is down-regulation?

A process by which a cell decreases the quantity of a cellular component in response to an external variable; also called desensitization.

What is a first messenger?

An extracellular ligand that binds to a cell surface receptor and initiates intracellular activity.

What are ligands?

Substances such as neurotransmitters, medications, and hormones that bind to receptors in the autonomic nervous system.

What is a second messenger?

The molecule inside the cell that acts to transmit signals from a receptor to the target.

What is the second messenger?

The link between events occurring outside the cell.

What is signal transduction?

When receptors on target tissues are stimulated by a ligand, initiating a cascade of intracellular events.

What is up-regulation?

A process by which a cell increases the quantity of a cellular component in response to an external variable; also called hypersensitization.

What is acetylcholine?

A neurotransmitter in the cholinergic system with high concentrations in the motor cortex and basal ganglia; it has excitatory effects at synapses and inhibitory effects at some peripheral sites.

What is the function of acetylcholinesterase?

An enzyme that breaks down acetylcholine into choline and acetate, mainly found at neuromuscular junctions.

What is Alzheimer disease (AD)?

The most common type of dementia, characterized by significant neuron loss and the presence of plaques and neurofibrillary tangles.

What are cholinergic drugs?

Agents that stimulate the parasympathetic nervous system in the same manner as acetylcholine.

What is myasthenia gravis (MG)?

A chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of skeletal muscles.

What does akinesia refer to?

Rigid limbs.

What is an anticholinergic drug?

A drug that inhibits the actions of acetylcholine in the brain.

What is an antimuscarinic drug?

A drug that interacts with muscarinic cholinergic receptors to produce an anticholinergic response.

What are the basal ganglia?

An area in the midbrain that controls smooth voluntary movement.

What is bradykinesia?

Inability to move.

What is a catechol-O-methyltransferase (COMT) inhibitor?

A medication that inhibits the metabolism of levodopa in the periphery.

What is cycloplegia?

Paralysis in the ciliary muscle of the eye.

What is a dopamine receptor agonist?

A drug that increases levels of dopamine to correct neurotransmitter imbalance.

What is a hypertensive crisis?

A severe increase in blood pressure that can lead to a stroke.

What are muscarinic receptors?

Receptors located in most internal organs that may be excited or inhibited by acetylcholine.

What is mydriasis?

Pupil dilation.

What are nicotinic receptors?

Receptors located in motor nerves and skeletal muscles that produce muscle contraction when activated by acetylcholine.

What is Parkinson disease?

The most common form of parkinsonism, characterized by resting tremor, bradykinesia, rigidity, and postural instability.

What is parkinsonism?

A general term for neurologic disorders that cause problems with movement.

What are quaternary amines?

Anticholinergic drugs that are lipid insoluble and do not readily cross cell membranes.

What is the substantia nigra?

A region of the midbrain with dopamine cells.

What are tertiary amines?

Anticholinergic drugs that are lipid-soluble and can cross cell membranes.

What does 'wearing off' refer to?

Periods when medication is not working well, causing worsening of parkinsonian symptoms.

What are antiepileptic drugs?

Drugs used to control seizures or convulsions.

What is clonic?

Spasms that alternate between contraction and relaxation.

What is the clonic phase?

Rapid rhythmic and symmetric jerking movements of the body.

What is a convulsion?

A tonic-clonic type of seizure characterized by spasmodic contractions of involuntary muscles.

What is epilepsy?

A condition where the patient has repetitive seizures.

What is gingival hyperplasia?

Overgrowth of the gums related to long-term administration of phenytoin.

What is malignant hyperthermia?

A rare but life-threatening complication of anesthesia characterized by hypercarbia and metabolic acidosis.

What is a muscle spasm?

A sudden, involuntary, painful muscle contraction.

What is a seizure?

A brief episode of abnormal electrical activity in nerve cells of the brain.

What is spasticity?

A condition caused by nerve damage that involves increased muscle tone and stiff movements.

What is status epilepticus?

Repeated seizures or a seizure lasting at least 30 minutes.

What is tonic?

Muscle spasms with sustained contraction.

What is a tonic-clonic seizure?

The most common type of seizure, often referred to as a major motor seizure.

What is the tonic phase?

Sustained contraction of skeletal muscles with abnormal postures.