Pharmacological agents used in medical imaging

 Pharmacological agents used in medical  imaging

Pharmacological agents

 Used in medical imaging

we'll be looking at their functions

dosage how they're administered

side effects and contraindications.

A radiographic image

Contrast media are not the only pharmacological agents or drugs used in radiography other drugs you'll find being used in a radiology department include antispasmodics gastrocnemius antihistamines and steroids.

The antispasmodic example of this is hycacine n-butyl bromide commonly marketed as buscopan is an anti-cholinergic this means that it blocks the acetylcholine receptor preventing acetylcholine from working now acetylcholine is a neurotransmitter that causes increased intestinal motility and gastric secretion it practically increases bowel movement thus when buscopan blocks the activity of acetyl column bowel movement is reduced this is good because when the abdomen is being radiographically examined bowel movement causes movement on sharpness thus when buscopan is used to reduce intestinal motility greater image quality is observed as there is less movement on sharpness buscopan is usually administered intravenously with a dosage of 20 milligrams.

The major advantage of buscopan is its low cost

however, it causes antimuscarinic side effects like blurred vision dry mouth tachycardia gastric dilatation, and urinary retention

because of these side effects, boscopan should not be used on patients with angle-closure glaucoma this is a rare type of glaucoma in which the drainage system of the eye is obstructed causing a build-up of pressure within the eye buscopan would only make this worse also patients with paralytic alias should not use buscopan in paralytic alias there is already little or no bowel movement buscopan would worsen the condition of such a patient it is also contraindicated in prostatism this is because patients with prostatism suffer urinary retention

which is also one of the side effects of boscopan another anti-spasmodic is glucagon commonly marketed as glycogen you probably know glucagon is a hormone that stimulates the production of sugar apart from this function glucagon also helps to reduce intestinal motility and gastric secretion producing effects similar to those of boscopan.

 The dosage for glucogen is 0.3milligram per kilogram of the patient for a barium meal and one milligram per kilogram for a barium enema

 It is also administered intravenously glucagon is a more powerful anti-spasmodic than buscopan also, it acts for a short period of time this is good because it prevents it from interfering with the bowel transit time what this means is that while you need an anti-spasmodic to prevent bowel movement you wouldn't want it to act for too long on the bowel because if it acts for too long it will cause a delay in the movement of the stomach contents to the small intestine in a barium follow-through exam contrast media needs to move from the stomach to the small intestine if the antispasmodic stops bowel movement for too long this movement of contrast media is delayed and the examination is made longer so by acting for a short period of time glucagon ensures the exam is not prolonged due to slower gastric emptying a disadvantage of glucagon however, is that it is more expensive than Busco pam and because it is a protein molecule it has a tendency to cause hypersensitivity reactions it is contraindicated in conditions like glucagonoma insulinoma and the chromosotoma.

Another type of pharmacological agent used is the gastrokinetic agent an example is metaclopramide commonly marketed as maxillon while antispasmodics prevent intestinal motility and gastric secretion the stroconetic agents perform the exact opposite they are dopamine antagonists this means that they prevent the action of dopamine causes decreased intestinal motility and gastric secretion thus by preventing the action of dopamine gastrokinetic agents like maxillon cause increased intestinal motility and gastric secretion with faster bowel movements contrast media travels from the stomach to the small intestine in less time this allows barium follow-through investigations to be performed faster maxillon is administered orally or intravenously with a dosage of 20 mg like we have mentioned maxillon speeds up the exam time by allowing barium to transit faster from the stomach to the small intestine another advantage is that it has an antiemetic effect this means that it prevents vomiting this is very helpful in nauseated patients however maxillon causes certain drug-induced movement disorders are known as extrapyramidal side effects examples of these are irregular movements muscle spasm and tremor this is observed especially at high doses of maxillon next antihistamines an example is diphenhydramine commonly marketed as Benadryl.

 Histamines can be released when contrast media is administered on a patient and these histamines cause many inflammatory reactions leading to symptoms like itching and flushing benevole helps to block the histamine receptor preventing the action of histamine 50 milligrams of Benadryl is given intravenously immediately before administering contrast media

its side effects include drowsiness

blurred vision and dry mouth next is steroids one example is methylpernicilone commonly marketed as medull it is the immune system that produces the chemicals that mediate contrast media reactions

steroids are potent immunosuppressants they suffer the actions of the immune system preventing many contrast media reactions from happening to meddle is commonly in a tablet form and is administered in two oral 32-milligram doses the first dose is given 12 hours before contrast media is administered

while the second dose is given two hours before contrast media

its side effects include nausea vomiting headaches and sweating another type of steroid is hydrocortisone commonly marketed as soulcordith like methylpernicillon it suppresses the

immune system and prevents contrast media reactions its dosage is 200 milligrams administered

intravenously immediately before contrast media is given this is where its advantage over

mithilpurnicus alone lies if you remember methopreness alone has to be given 12 and two hours before

contrast media for it to work this means that it cannot be used for emergency examinations that require

contrast media hydrocortisone on the other hand does not need to be given in advance

if an emergency examination comes up it can be given immediately and still work also hydrocortisone is administered intravenously making it useful for patients who are unable to take oral medications

its side effects include nausea headaches and diarrhea