Prototype: dimenhydrinate (PO, IM IV)- nonprescription OTC drug

Action: inhibits vestibular stimulation in the middle ear-to prevent motion sickness, n/v, vertigo;

• also used to prevent or alleviate allergic reactions by acting as an antagonist to histamine (H1) receptors 

Contraindications:

• NOT FOR PTS W GLAUCOMA - increases intraocular pressure
• Urinary retention or obstruction
• Asthma

Side effects:

• Anticholinergic effects- drowsiness/dizziness, dry mouth, blurred vision tachycardia, constipation, restlessness headache
• SEDATION 

Considerations: antiemetics can mask the underlying cause of vomiting- should not be used until it has been determined (unless so severe to cause dehydration + e- imbalances)

Pt teaching:

• Take 30 mins before traveling
• Increase fluid intake, suck on hard candy or chew gum to relieve dry mouth 
• Void every 4 hrs + palpate lower abdomen q 4-6 hrs to check bladder for fullness
• Avoid activities that require alertness (driving)

Prototype: Scopolamine (transdermal patch behind ear 4 hrs before travel; replace q 3 days)

Action: ask, primarily on the vomiting center in the brain decreases stimulation of CTZ + vestibular center in the ear- for motion sickness, post op n/v

Contraindications: glaucoma, urinary retention or obstruction, asthma

Side effects: dizziness/drowsiness, dry mouth, blurred vision (pupillary dilation), tachycardia, constipation

Considerations: 

Pt teaching

• Take 30 mins before traveling, if using patch- four hours before travel
• Increase fluid intake, suck on hard candy or chew gum to relieve dry mouth 
• Void every 4 hrs + palpate lower abdomen q 4-6 hrs to check bladder for fullness

Prototype: Promethazine

Action: act on chemo trigger zone, block dopamine 2 receptors- relief of postop n/v, chemotherapy/radiation sickness

Contraindications: glaucoma, urinary retention, obstruction, asthma, e- imbalances (hypoK, hypoCal, hypoMg), older adults, breastfeeding

Side effects:

• Acetylcholine effects- HYPOTENSION + EPS (restlessness, anxiety, spasms of face/neck)
• SEDATION
• adverse- EPS, low blood count
• Drug interactions:
  • ↑ CNS depression and ACh effects w ETOH + other CNS depressants
  • ↓ effects of phenytoin (seizure med)

Considerations:

• obtain orthostatic blood pressure + pulse readings, RR+ ECG before therapy, and periodically- monitor for Q and T wave changes

Action: Stimulates chemo trigger zone + acts directly on gastric mucosa- induces vomiting after a non-toxic substance is ingested

• Avoid vomiting if substance is caustic or petroleum- get pt to hospital and charcoal or gastric lavage can be used
• only use an emetic if you know what the person has ingested

caustic substances: ammonia, chlorine bleach, lye, toilet cleaners, battery acid

Prototype: diphenoxylate w atropine (Lomotil)

Action: opioid related agent- decreases GI motility + hypersecretion to relieve diarrhea

Contraindications: glaucoma (increases ICP), severe hepatic impairment, children/older adults (more susceptible to resp depression), severe diarrhea due to infx, UC, breastfeeding

Side effects:

• physical dependence, 
• constipation
• dizzy, drowsy, headache, n/v
• ADVERSE- Ileus/toxic megacolon, resp depression
• Drug interactions:
  • CNS depression when taken w ETOH sedatives or tranquilizers
  • MAO inhibitors- ups HTN crisis

Considerations:

• do not use for more than 2 days or if fever is present- if fever present, want the pt to have the diarrhea to purge the bacteria
• give max 8 tabs per day

Prototype: Docusate sodium (Colace)

Action: lowers surface tension by promoting water accumulation and emulsification of feces for easier poop- prevents constipation + decreases straining during defecation (MI and post surg pts)

Contraindications:

• diarrhea/vomiting, e- imbalances
• GI bleeding or inflammation- diverticulitis, appendicitis, UC
• GI obstruction fecal impaction, abdominal pain
• preg/breastfeeding 

Side effects:

• n/v, diarrhea, mild abd cramping, rectal irritation
• reddish brown urine
• F/E imbalances (Ca and K)- hypokalemia hypocalcemia!!!
• Drug interactions:
  • ↓ effect w antacids, H2 blockers, PPIs

Considerations: 

Pt teaching:

Prototype: Bisacodyl (Dulcolax)

Action: ↑ peristalsis by irritating intestinal mucosa/smooth muscle- produces watery stool - used as bowel prep for surgery or dx procedures

Contraindications:

• undiagnosed abd pain
• GI inflammation/bleeding (UC/Crohns, appendicitis, diverticulitis)
• spastic colon, bowel obstruction
• pregnancy (avoid stimulant laxatives)

Side effects:

• nausea, diarrhea, mild abdominal cramps
• reddish-brown urine
• F/E imbalances (esp Ca and K+)- 
• HYPOKALEMIA!!!!! HYPOCALCEMIA!!!! - tetany + dysrhythmias
• weakness
• rectal irritation

Prototype: Psyllium (Metamucil)

Action: absorb water into intestines, increase bulk like fiber does + increases peristalsis- promotes large, soft stools

• promote defecation in diverticulosis, control stool for ostomy pts + decrease diarrhea in IBS

Contraindications:

• older adults, pregnancy, dysphagia
• Undiagnosed, abdominal pain
• GI bleeding or inflammatory disorders 
• GI obstruction 

Side effects:

• Excessive use- n/v, diarrhea, cramps, flatus
• ADVERSE- Insufficient fluid intake causes intestinal obstruction, BRONCHOSPASM ANAPHYLAXIS
• Drug interactions: ↓ absorption of oral anticoagulants, aspirin, and digoxin

Considerations/pt teaching:

• Admin- mix in a glass of water or juice, stir and drink immediately; follow with an 8 ounce glass of water

Prototypes: Osmotic laxatives (magnesium hydroxide)

Action: hyperosmolar salts pull water into colon + increase water in feces to increase bulk - stimulates peristalsis and defecation; produces semiformed to watery stool

• Used as bowel prep for dx procedures or surgery, rids body of dead parasites/poisons

Contraindications:  renal insufficiency, 

Side effects:

• N/V, diarrhea, cramps, flatulence
• f/e imbalances (hyper Mg)- hypotension, heart block, drowsiness, weakness, paralysis, flush, resp depression 

Considerations: Monitor serum electrolytes to avoid imbalance

Pt teaching: 

Prototype:  Bismuth subsalicylate

action: coats wall of GI tract and adsorbing bacteria/toxins causing diarrhea

side effects:

• inner ear problems- dizziness, drowsiness, headache, weakness
• BLACK TONGUE + POOP