Drugs Flashcards
Which category of drug competitively antagonizes acetylcholine (vagal tone)?
Anticholinergics
What do anticholinergics inhibit and how do they do so?
- Bradycardia
- By decreasing vagal tone.
What might anticholinergics cause?
Sinus Tachycardia
What do anticholinergics reduce?
Glandular secretions
What effect do anticholinergics have on gastric pH?
Increase gastric pH
What effect do anticholinergics have on gastrointestinal motility?
Decrease gastrointestinal motility
What are two common side effects of anticholinergics?
- Bronchodilation
- Mydriasis
Which two anticholinergics may produce drowsiness?
- Atropine
- Scopolamine
Which anticholinergic does not cross the blood-brain barrier or placental barriers?
Glycopyrrolate
Which anticholinergic may slow the heart rate (bradycardia) temporarily after IV administration?
Atropine
What type of cardiac arrhythmias can atropine or glycopyrrolate cause if given IV?
What else can atropine given IV cause?
- First and second degree AV blocks before sinus tachycardia.
- Ventricular arrhythmias
What might atropine cause in dogs & cats?
In ruminants?
- Depression
- Restlessness
What might anticholinergics cause in horses?
In ruminants?
- Colic
- Bloat
What do phenothiazines cause?
Calming and muscle relaxation.
What are 3 effects phenothiazines have?
- Antiemetic
- Antiarrhythmic
- Antihistaminic
What do phenothiazines do to analgesics?
Potentiate analgesics
Where are phenothiazines metabolized?
Liver
What is the normal DOA for phenothiazines?
Effects can be seen for up to how long?
- 4 to 8 hours
- Up to 48 hours
Can phenothiazines cause hypertension or hypotension?
Hypotension
Can phenothiazines cause hyperthermia or hypothermia?
Hypothermia
What do phenothiazines inhibit?
Platelet aggregation
T/F: Phenothiazines are analgesic.
False - They are not analgesic.
What is the concern with using phenothiazines in an epileptic patient?
They may lower seizure threshold in animals with epilepsy.
What are 2 side effects seen with excessive doses of phenothiazines or butyrophenones?
Which species is particularly susceptible?
- Apparent involuntary musculoskeletal effects and hallucinatory activity.
- Horses
What side effect with phenothiazines can be seen in Boxers?
Occasional bradycardia
What effect do intrahepatic or extrahepatic shunts have on phenothiazines?
Increased duration of action.
