GI DRUGS (in progress)

Antisialagogues

Medications that reduce or inhibit the flow or saliva and oral secretions

↓ GI secretions (includes saliva) by inhibiting effects of acetylcholine

Atropine

Side effects: Dry mouth, constipation, tachycardia, dilation of pupils, CNS stimulation

Glycopyrrolate

(safer in pregnant animals – little chance of crossing blood-brain or placental barriers)

•Side effects: Dry mouth, constipation, tachycardia, dilation of pupils, CNS stimulation

Antidiarrheals - Anticholinergics

•For:  tenesmus & vomiting (related to colonic irritation)

•How: block acetylcholine release

•Atropine

•Aminopentamide (DISCONTINUED)

•Methscopolamine

•Propantheline

Antidiarrheals - Narcotics

•↑ fluid absorption by

•↓ GI secretions & peristaltic contractions

•↑ segmental contractions by combining with mu opioid receptors

Loperamide (Imodium®)

Causes less CNS depression

Side effects: CNS depression (excitement in cats & horses), ileus, bloat, constipation, urinary retention

Diphenoxylate (Lomotil®)

Includes atropine to discourage human abuse

Side effects: CNS depression (excitement in cats & horses), ileus, bloat, constipation, urinary retention

Paregoric (Controlled)

opium derivative

Side effects: CNS depression (excitement in cats & horses), ileus, bloat, constipation, urinary retention

Antidiarrheals - Protectants & Adsorbents

•Protectants = coat mucosa

•Adsorbents = binding bacteria, toxins, drugs, etc.

•May affect absorption of other drugs

Bismuth subsalicylate(Pepto-Bismol®) NOT BEST OPTION

•Protectant + adsorbent

•Coats mucosa & is anti-endotoxic + anti-inflammatory

•Aspirin-like CAREFUL DOSING WITH CATS

Side effects: black stool, radiographic opacities

Kaolin/pectin (Kaopectate®) NOT BEST OPTION

•Aspirin-like CAREFUL DOSING WITH CATS

•Protectant + adsorbent 

Activated charcoal

Potent Adsorbent – do not give with other drugs * alcohol (xylitol), petroleum, metals

Probotics

•Seeds GI with good bacteria

•Lactobacillus spp., Enterococcus faecium

•Plain yogurt with active cultures

•FortiFlora®

•Mycequin®

Antidiarrheals - Antibiotics

•↓ bacteria (primarily anaerobic) that cause GI inflammation

•Directly ↓ GI tract response to inflammatory stimuli

•Side Effects:  ↑ dose or long term = CNS effects

Metronidazole

•↓ bacteria (primarily anaerobic) that cause GI inflammation

•Directly ↓ GI tract response to inflammatory stimuli

•Side Effects: @ ↑ dose or long term = CNS effects

Tylosin

•Extra-label use in cats/dogs for bacterial overgrowth, IBD, & colitis due to clostridial bacteria

Appetite Stimulates

Nutrition Maintains Life/Heals, Support enterocyte health, Optimal immune function, Cats susceptible to hepatic lipidosis (‘fatty liver’)

Mirtazapine- Dogs/cats

Cyproheptadine- Cats

Laxatives & Cathartics

Categories: Emollient and Bulk laxatives; Osmotic and Irritant cathartics

Chronic constipation, hairball removal, empty colon prior to procedure, ease stool passage post surgery/trauma

•PO or suppository

Emollient Laxatives (lubricant oils)

Best for recovery from anal surgeries, or other rectal ailments

•Docusate agents, Change surface tension of feces: water can penetrate stool

•Mineral oil (careful: PO; aspiration, swallowing reflex*)

•Cod liver oil or white petroleum (Laxatone®)

•Glycerin (most common as suppository)

Bulk Forming Laxatives

•Indigestible plant fiber, absorb water into intestine,  feces softens as it retains water.

•Benefits: Largely natural, Produce normal, soft but formed stool, Minimal effects on nutrient absorption

•Psyllium (Metamucil®)

•Bran

Osmotic Cathartics

•Hypertonic salts OR non-digestible sugars , Draw water into colon & then feces

•Magnesium causes a hormone release that ↑peristalsis

•Caution: Electrolyte imbalances may occur!, Some are contraindicated in cats & dogs (Fleet Enema®)

Lactulose (PO)

less electrolyte imbalances

•can be used to eliminate ammonia in liver disease

Magnesium hydroxide

(PO) (Milk of Magnesia®)

Dioctyl Sodium Sulfosuccinate

(DSS) enema

Irritant Cathartics

•↑ peristalsis by irritating GI nerve endings

Not for Use = suspected obstructed bowel, impacted feces, tenesmus from colonic irritation, Hx rectal/anal Sx

Bisacodyl (Dulcolax®)

Enterically coated, so do not crush or chew = severe cramping

DO NOT administer milk or antacids within 1 hr = cramping

Castor oil

is converted the duodenum to ricinolein acid which is highly irritating

Emetics

Two categories: Centrally acting emetics & Locally acting emetics

Vomit inducing for: overdoses, accidental ingestion, poisoning

•Always check with poison control first

•Protracted nausea/retching post emesis: Treat with anti-emetic

1. Centrally Acting Emetics

Apomorphine

•Stimulates dopamine receptors in CRTZ

•IV –rapid

•Conjunctiva – 10-20 mins (rinse post)

•Canine emetic of choice

•Side effects:

•Protracted vomiting, CNS depression, restlessness

Dexmedetomidine

IV, IM - emetic of choice in cats

Xylazine (Rompun®)

•IV, IM - cats

•Side effects:

•Bradycardia, ↓ respiratory rate, hypotension

Anticholinergics:

UNWANTED SIDE EFFECTS, BETTER OPTIONS EXIST, REGARDED AS INEFFECTIVE

•For:  tenesmus & vomiting (related to colonic irritation)

•How: block acetylcholine release

•Drugs:

•Atropine

•Aminopentamide (DISCONTINUED)

•Methscopolamine

•Propantheline

Loperamide (Imodium®)

Causes less CNS depression

Side effects: CNS depression (excitement in cats & horses), ileus, bloat, constipation, urinary retention

Diphenoxylate (Lomotil®)

Includes atropine to discourage human abuse

Side effects: CNS depression (excitement in cats & horses), ileus, bloat, constipation, urinary retention

Stimulant Laxatives

•↑ peristalsis by irritating GI nerve endings

Not for use: suspected obstructed bowel, impacted feces, tenesmus from colonic irritation, Hx rectal/anal Sx