Clinical Pharmacology Flashcards
What are the groups of drugs used to treat GI disease?
Acid suppression Drugs affecting GI motility Laxatives Drugs for IBD Drugs affecting intestinal secretions
What are the acid suppression drugs?
Antacids
H2 receptor antagonists
Proton pump inhibitors
What are the drugs affecting GI motility?
Anti-emetics
Anti-muscarinics
Anti-motility
Which drugs are used to treat IBD?
Aminosalicylates
Corticosteroids Immunosuppressant’s
Biologics
What do anti acids contain?
Magnesium or aluminium
How do antiacids work?
Neutralise gastric acid
When should anti acids be used?
When symptoms occur
What is common example of a over the counter anti acid?
Rennie
What is an alginates?
A viscous gel that floats on stomach contents and reduces reflux
How do H2 receptor antagonists work?
Block histamine receptor thereby reducing acid secretion
When are H2 receptor A indicated?
In GORD or peptic ulcer disease
How are H2 receptor antagonists given?
Orally or IV
How do PPI work?
Block proton pump and thereby reduce acid secretion
When are PPI indicated?
GORD
Peptic ulcer disease
What do pro kinetic drugs do?
Increase gut motility and gastric emptying
What are pro kinetic drugs good for treating?
Vomiting
Why are prokinetic drugs good for relieving vomiting?
Because they empty the stomach
and once food has left the stomach it cannot reflux back up
What is the mechanism for prokinetic drugs?
Mechanism is unknown
but involves parasympathetic NS control of smooth muscle and sphincter tone
What is the mechanism of drugs that decrease GI motility?
Operate via opiate receptors in GI tract to decrease Ach release
Decreases smooth muscle contraction
Increases anal sphincter tone
Symptoms of which diseases can be treated with anti-spasmodics?
IBS
Renal colic
What are the 4 types of laxatives?
Bulk
Osmotic
Stimulant
Softeners
How do laxative work?
Work by increasing bulk or drawing fluid into the gut
What do osmotic laxatives require to work?
Adequate fluid intake
What are the two routes of admission for laxatives?
Oral
Rectal
What drugs are given to treat IBD?
Aminosalicylates Corticosteroids Immunosuppressants Biologics Infliximab
How do corticosteroids treat IBD?
Have anti-inflammatory effects to treat the inflammation in IBD
How are corticosteroids given?
Orally
IV
Rectally
What should you not do with any patient on long term steroid courses?
DO NOT withdraw them suddenly from treatment
What do immunosuppressants prevent?
Immune cell proliferation
What is required with the treatment with immunosuppressants?
Specialist use and close monitoring
What is an example of a commonly used biologic?
Infliximab
What do biologics reduce in IBD?
Inflammation
Do biologics treat the undelying disease in IBD?
No
What is the main adverse effect when using immunosuppressants?
Mainly related to bone marrow suppression
What other conditions are biologics used in?
Psoriasis
Rheumatoid Arthritis
What is the malignancy rate in the use of Infliximab?
1-2%
What are the contraindications of the use of infliximab?
MS Current TB Current serious infection Pregnancy Breastfeeding
What is the mechanism of cholestyramin?
Relieves itching from jaundice
What is a side affect of cholestyramin?
Is highly bindable to other drugs
What is ursodeoxycholic used to treat?
Gallstones and primary biliary cirrhosis
How does ursodeoxycholic work?
Inhibits the enzyme that is involved in the formation of cholesterol
What are the 4 stages of pharmacology?
Absorption
Distribution
Metabolism
Excretion
Is diarrhoea and constipation an acute or chronic condition?
Can be either
What is the most common cause of bowel changes?
Antibiotic treatment
What is the most common cause of GI bleeding?
Low dose aspirin
What is the 3rd most common cause of GI bleeding?
Warfarin
What are changes in gut bacteria mainly due to?
Use of AB
When using Ab and experiencing diarrhoea what can lose its effectiveness?
OCP
so use another form of contraception if taking the pill and on AB
What are the risk factors for hepatotoxicity?
Age (older)
Sex (female)
Alcohol consumption Genetics
Malnourishment
What is intrinsic hepatotoxicity?
Hepatotoxicity due to a predictable drug
Is dose dependant
Is an acute situation
What is idiosyncratic hepatotoxicity?
Hepatotoxicity due to an unpredictable drug
Can occur at any time Not dose dependant
What scoring system grades liver failure patients?
Child-Pugh classification
What score qualifies for group A in Child-Pugh Classification?
<7
What score qualifies for group b in Child-Pugh Classification?
7-9
What score qualifies for group C in Child-Pugh Classification?
> 9
What score is often used for liver transplantation scoring?
Child-Pugh Classification
What drugs will worsen encephalopathy?
Diuretics
What drugs should be avoided in liver disease?
Warfarin/anti-coagulants
Aspirin
NSAIDS
Opiates
Where should you refer to for drug information?
BNF
Why should opiate be avoided in liver disease patients?
may precipitate encephalopathy by increasing sedation