Pharm

• Anatomy and Physiology Review: The gastrointestinal system includes the mouth, tongue, salivary glands (parotid, sublingual, and submandibular), pharynx, esophagus, stomach, liver, gallbladder, pancreas, spleen, small intestine (duodenum, jejunum, ileum), and the large intestine (transverse, ascending, descending, and sigmoid colon; cecum, appendix, rectum, anal canal, and anus).

• Abdominal Assessment: Nursing process requires thorough documentation of bowel patterns and localized abdominal assessments.

• Medication Interactions and B12 Absorption: Nurses must assess for potential interactions and remain aware that any alteration in stomach acidity levels can lead to vitamin $B12$ malabsorption.

• Chest Pain Differentiation: Reports of chest pain require a focused cardiac assessment. Cardiac conditions may be misdiagnosed by patients who report "heartburn."

• Patient Notification and Safety: If clinical improvement is not observed, the provider must be notified. New symptoms, such as coughing or vomiting of blood (hematemesis) or increased pain, must be reported immediately as they may indicate a life-threatening bleeding ulcer.

Peptic Ulcer Disease (PUD) and Gastric Acid Management

• Pathophysiology of PUD: Occurs when gastric or duodenal ulcers are formed due to the breakdown of GI mucosa by pepsin and the caustic effects of hydrochloric acid.

• Risk Factors: PUD is the most harmful disease related to hyperacidity and can result in life-threatening bleeding ulcers. Hospitalized patients often experience stress-related mucosal damage.

• Prophylaxis: Many post-operative or critically ill patients receive medication specifically to prevent stress ulcer formation.

• Antacids:

  • Function: Neutralize existing stomach acid to reduce heartburn symptoms.

  • Examples: Calcium carbonate, aluminum hydroxide, and magnesium hydroxide.

  • Side Effects: Calcium and aluminum compounds can lead to constipation; magnesium compounds cause diarrhea and rhd

  • Contraindications: Magnesium-based antacids should be avoided in patients with impaired renal function.

  • Administration Timing: Wait $1$ hour before taking H2 receptors to avoid decreased absorption. Wait $1$ to $2$ hours before taking other medications when using aluminum compounds.

• H2-Receptor Antagonists:

  • Mechanism of Action: Block histamine at the H2 receptor of the parietal cell, decreasing hydrochloric acid production.

  • Examples: Famotidine, cimetidine (suffix "-dine").

• Proton Pump Inhibitors (PPI):

  • Mechanism of Action: Bind to the hydrogen-potassium ATPase enzyme system ("proton pump") of the parietal cell, inhibiting HCl secretion.

  • Duration: The antisecretory effect lasts longer than $24$ hours.

  • Examples: Pantoprazole, omeprazole (suffix "-zole").

  • Patient Education: Discourage use of alcohol, NSAIDs, and GI-irritating foods.

• Mucosal Protectants (Sucralfate):

  • Mechanism of Action: Locally coat the ulcer site to protect against acid, pepsin, and bile salts; minimally absorbed by the GI tract.

  • Administration: Must be given on an empty stomach, either $2$ hours after or $1$ hour before meals.

  • Precautions: May cause constipation. Use cautiously in chronic renal failure or dialysis patients due to potential accumulation of small amounts of absorbed aluminum.

Pathophysiology and Treatment of Diarrhea and Flatulence

• Definition of Diarrhea: The passage of $3$ or more loose or liquid stools per day, or a higher frequency than is baseline for the individual.

• Causes: Bacteria (contaminated food/water), viruses (influenza, norovirus, rotavirus), parasites, medications (antibiotics, cancer drugs, magnesium antacids), food sensitivities, and diseases like Crohn's or IBS.

• Primary Danger: Dehydration due to loss of water and electrolytes. Severe cases require rehydration via oral solutions or IV fluids.

• Adsorbents (Bismuth Subsalicylate):

  • Action: Coat GI walls and bind bacteria/toxins for elimination in stool.

  • Patient Education: Stool color changes may occur. The medication contains aspirin. Discontinue use if tinnitus (ringing in the ears) occurs.

• Anticholinergics (Hyoscyamine):

  • Action: Inhibit propulsive motility by working on smooth muscle; decrease gastric acid secretion.

  • Education: May cause dizziness or drowsiness. Frequent oral hygiene helps alleviate dry mouth.

• Opiate-like Medications (Loperamide):

  • Action: Decrease fluid/electrolyte flow into the bowel and slow movement to reduce the number of stools.

  • Education: Avoid alcohol and CNS depressants; may cause drowsiness.

• Probiotics (Lactobacillus):

  • Usage: Used to prevent and treat diarrhea, often concomitantly with antibiotics to replenish normal bacterial flora.

• Anti-flatulents (Simethicone):

  • Action: Alter elasticity of mucous-coated gas bubbles, causing them to break into smaller bubbles for easier expulsion.

  • Education: Encourage movement (ambulation), position changes, avoiding straws, and tapering intake of beans and cruciferous vegetables.

Management of Constipation

• Definition: Three or fewer bowel movements per week; stools that are hard, dry, lumpy, or painful/difficult to pass.

• Causes: Lack of fluid or fiber, immobility (lack of ambulation), surgical anesthesia, opiates, and certain medications.

• Assessment: Document discomfort, distention, bowel sounds, and the date of the last movement. Notify providers for absent bowel sounds, worsening pain, extreme distension, or "smearing" of stool (possible blockage/ileus).

• Pharmacological Classes:

  • Fiber Supplements (Psyllium): Add bulk to stool. Must be mixed with at least $8$ ounces of fluid. Administer at least $2$ hours apart from other meds to prevent absorption interference.

  • Stool Softeners (Docusate): Move water and fats into stool. Produce movement in $12$ to $72$ hours.

  • Osmotic Agents (Polyethylene Glycol): Retain water in the stool. Produce movement in $1$ to $3$ days; may cause watery stools.

  • Lubricants (Fleet Enema): Coat stool to seal in water. Produce movement in $2$ to $15$ minutes; may cause cramping or bloating.

  • Stimulants (Bisacodyl): Induce intestinal contraction. Available in oral or rectal forms. Instruct patients to retain suppositories for $15$ to $20$ minutes. Movement typically occurs in $15$ minutes.

Nausea and Vomiting (Antiemetics)

• General Nursing Care: Monitor hemoglobin ($Hgb$), hematocrit ($Hct$), and serum sodium ($Na$) for signs of dehydration. Maintain strict intake/output (I/O) records. Administer antiemetics in advance of meals if appetite is affected.

• Nonpharmacological Interventions: Sips of clear liquids every few minutes; eating bland, non-spicy, low-fat foods; and avoiding strong triggers.

• Anticholinergics (Scopolamine Transdermal):

  • Action: Block ACh receptors in the vestibular center to prevent stimuli to the Chemoreceptor Trigger Zone (CTZ) and Vomiting Center (VC).

  • Precautions: Impairs hazardous tasks (driving, machinery). Contact with eyes causes temporary pupil dilation and blurred vision.

• Antihistamines (Meclizine):

  • Action: Block H1 receptors in the vestibular center. Contraindicated in glaucoma or enlarged prostate. Take $1$ hour before travel.

• Dopamine Antagonists (Prochlorperazine):

  • Action: Block dopamine in the CTZ and calm the central nervous system.

  • Education: Avoid alcohol/CNS depressants. Urine may turn pinkish to reddish-brown. Increased photosensitivity.

• Prokinetics (Metoclopramide):

  • Action: Promote peristalsis. (Increase Gi motility)

  • Warning: Notify provider for new depression or dyskinesia which is abnormal muscle movements (lip smacking, puckering, tongue protrusion, blinking, shaking of limbs).

• Serotonin Antagonists (Ondansetron):

  • Action: Block serotonin receptors in the GI tract, CTZ, and VC.

  • Adverse Effects: QT prolongation (abnormal cardiac rhythm). Serotonin Syndrome risk if taken with SSRIs.

• Neurokinin Receptor Antagonists (Aprepitant):

  • Action: Inhibits substance-P receptors. Interacts with warfarin and birth control.

• Tetrahydrocannabinoids (THC/Dronabinol):

  • Action: Alter mood and perception in the cerebral cortex. Stimulates appetite. Is a scheduled (abusable) medication that cause a "high."

• Herbal Supplements: Ginger (antagonizes 5HT receptors), Peppermint, and Pyridoxine (Vitamin $B6$) for pregnancy-induced nausea.

Central Nervous System (CNS) Nursing Process

• Assessment Focus: CNS assessments rely heavily on subjective data (feelings, thoughts, behaviors). Cumulative effects may occur when multiple CNS drugs are used.

• Therapeutic Timeframe: Many CNS medications take several weeks to produce therapeutic effects. Evaluation should monitor for improved mood, behavior, and movement (fewer abnormal movements and negative thoughts).

• Division of the Nervous System: The CNS (brain and spinal cord) and the PNS (all other nerves). The brain uses electrical impulses and neurotransmitters for communication.

Anxiety and Benzodiazepines

• Symptoms of Anxiety: Aches, racing heart, trembling, sweating, agitation, and sweating.

• Benzodiazepines (Lorazepam):

  • Action: Bind to GABA receptors. Used for sedation, anxiety, and anticonvulsant effects.

  • Nursing Considerations: Children and elderly may have paradoxical reactions (tremors, hallucinations). Must be tapered to avoid withdrawal.

  • Reversal Agent: Flumazenil for overdose.

  • Black Box Warning (BBW): Concomitant use with opioids leads to profound sedation, respiratory depression, coma, and death.

Depression and Antidepressants

• Diagnosis: Five symptoms (including depressed mood, fatigue, suicidal ideation, or insomnia) must be present for a $2$-week period.

• SSRIs (Fluoxetine):

  • Action: Inhibit serotonin reuptake.

  • Side Effects: Serotonin syndrome, decreased libido, urinary retention, and increased bleeding with NSAIDs, aspirin, or warfarin.

• SNRIs (Venlafaxine):

  • Action: Inhibit reuptake of serotonin and norepinephrine.

  • Side Effects: Sustained increase in blood pressure, hyponatremia, and elevated cholesterol.

• Tricyclics (Amitriptyline):

  • Action: Inhibit norepinephrine and serotonin uptake. Often administered at bedtime.

  • Side Effects: Anticholinergic effects (constipation, dry mouth) and cardiac conduction disturbances.

• MAOIs (Tranylcypromine):

  • Action: Inhibit monoamine oxidase, increasing levels of norepinephrine, dopamine, epinephrine, and serotonin.

  • Warnings: Hypertensive crisis when combined with tyramine-containing foods. Side effects can last weeks after discontinuation.

• General BBW for Antidepressants: Increased risk of suicide in children, adolescents, and young adults.

Seizure Disorders and Antiepileptics

• Definitions: Seizures are abnormal synchronous neuronal activity. Status Epilepticus is a seizure lasting > 20 minutes or repeated seizures without recovery (goal: control within $60$ minutes).

• Barbiturates (Phenobarbital): Depress the sensory cortex. Habit-forming. Don't stop abruptly.

• Phenytoin:

  • Therapeutic Level: $10 - 20\,mcg/ml$. Above this may cause psychosis or encephalopathy.

  • Warning: Fatal dermatologic reactions (Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis). Discontinue at the first sign of a rash.

• Levetiracetam: Monitor for psychotic symptoms and irritability. Can cause anaphylaxis or angioedema after the first dose.

• Gabapentin: Used for partial seizures and neuropathic pain. Do not take within $2$ hours of antacids.

Parkinson’s Disease (PD)

• Pathophysiology: Imbalance between dopamine and acetylcholine; deficiency of dopamine.

• Symptoms: Resting tremor, bradykinesia, muscle rigidity, and postural instability.

• Carbidopa/Levodopa:

  • Action: Levodopa crosses the blood-brain barrier; carbidopa prevents its breakdown in the periphery.

  • Side Effects: Hallucinations and intense impulse control disorders (gambling, sexual urges, spending). High-protein foods may impair drug action.

• Selegiline: Inhibits MAO-B. Used as an adjunct to levodopa. High doses carry risk of hypertensive crisis with tyramine.

• Amantadine: Antiviral that acts on dopamine receptors. May cause congestive heart failure and peripheral edema. Avoid use with OTC cold medications.