Pharmacology: Drugs in Radiography (Midterms)

Analgesics

● Analgesics are drugs that relieve pain and allow patients to

tolerate diagnostic or interventional procedures.

● They reduce discomfort from prolonged positioning or from

invasive imaging such as biopsy, drainage, or catheter insertion.

Common non-opioid examples

Paracetamol, Ibuprofen, Aspirin.

Common opioid examples

Morphine, Codeine, Tramadol.

Analgesics: Relevance to Radiography

● Relevance to radiologic technology is high because pain causes

involuntary movement leading to motion artifacts and repeated

exposures.

● Opioid analgesics can depress respiration and consciousness which

may complicate procedures using sedation or contrast.

● Non-steroidal anti-inflammatory analgesics such as Ibuprofen can

reduce kidney perfusion and increase the risk of contrast-induced

nephropathy especially in dehydrated or elderly patients.

● Technologists must check if the patient took pain medication before

the procedure because over-sedation may alter reaction to contrast or

delay recognition of complications such as contrast extravasation.

● Proper assessment of pain level before positioning improves patient

cooperation and image quality.

Anesthetic Agents

● Anesthetic drugs cause loss of sensation either locally or generally to minimize discomfort during procedures.

Local anesthetics

Lidocaine or Bupivacaine

Lidocaine or Bupivacaine

used for needle punctures, biopsies, and catheter placements

General anesthetics

Propofol or Sevoflurane

Propofol or Sevoflurane

used for lengthy or pediatric imaging where patient movement must be fully controlled

Anesthetic Agents: Relevance to Radiography

● Radiologic relevance is significant because these agents help

prevent movement during fluoroscopy, angiography, and MRI.

Anesthetic Agents

● However, anesthetics may depress respiration and cardiac function,

so continuous monitoring of oxygen saturation and heart rate is

required in the imaging suite.

● Interaction with iodinated or gadolinium contrast is minimal but

anesthetics can mask signs of allergic reaction such as restlessness

or discomfort.

● Technologists must be vigilant for physiological changes since

sedated patients may not communicate early symptoms of contrast

reactions.

● Collaboration with the anesthesia team ensures safety and proper

timing between anesthesia administration and image acquisition.

Antiallergic and Antihistamine Drugs

These drugs prevent or manage allergic responses triggered by contrast media or environmental factors in the radiology department.

Common antihistamines

Diphenhydramine, Loratadine, and Cetirizine.

Used as premedication for patients with a previous contrast allergy history?

Corticosteroids such as Prednisone

Antiallergic and Antihistamine Drugs: Relevance to Radiography

● Radiologic relevance is direct because contrast agents may cause

mild to severe hypersensitivity reactions ranging from hives to

anaphylaxis.

● These drugs block histamine receptors to prevent vasodilation,

itching, and bronchoconstriction during contrast exposure.

● They can cause drowsiness and reduced alertness which must be

considered when positioning or transferring the patient.

● Over-sedation from combined antihistamine and anxiolytic use can

suppress breathing and mimic contrast reactions.

● Technologists must confirm if prophylactic antihistamine or corticosteroid medication was taken before contrast administration and should be ready with emergency supplies such as oxygen and epinephrine.

Antianxiety Drugs

Antianxiety or anxiolytic drugs are used to reduce tension, fear, or panic during imaging procedures.

Examples of Antianxiety Drugs

Diazepam, Lorazepam, and Alprazolam.

Antianxiety Drugs: Relevance to Radiography

● They are particularly helpful for patients undergoing MRI who experience claustrophobia or those unable to remain still due to stress.

● Their relevance in radiologic technology lies in improving patient

cooperation and image quality.

● Excessive anxiety causes hyperventilation or muscle tension which can produce poor quality images.

● These drugs act on the central nervous system and may

lead to drowsiness, hypotension, or confusion.

● When combined with contrast agents, the risk of respiratory

depression increases if opioids or sedatives are also used.

● Technologists must ensure patients are accompanied

post-procedure and are closely monitored for dizziness or

delayed response.

● Proper explanation of the procedure can minimize the need

for pharmacologic anxiolysis

Antiarrhythmic Drugs

Antiarrhythmic agents stabilize abnormal heart rhythms.

Common examples of: Antiarrhythmic Drugs

Amiodarone, Lidocaine (IV use), and Digoxin.

Antiarrhythmic Drugs: Relevance to Radiology

● Radiologic relevance is highest in cardiac catheterization, CT angiography, or interventional procedures where heart

rhythm must remain stable.

● These drugs control the electrical conduction of the heart to

prevent tachycardia or fibrillation during stress or contrast

injection.

● Some antiarrhythmics can interact with iodinated contrast

causing exaggerated bradycardia or hypotension.

● Amiodarone in particular increases sensitivity to iodine and may

raise the risk of thyroid dysfunction after contrast exposure.

● Continuous ECG monitoring is essential when patients on

antiarrhythmics undergo contrast studies.

● Technologists should avoid unnecessary stress, maintain calm patient positioning, and report any irregular pulse or chest discomfort during imaging.

Antibacterial Drugs

● Antibacterial or antibiotic drugs destroy or inhibit bacterial growth.

Common examples of: Antibacterial Drugs

Penicillin, Cephalosporins, Macrolides, and Fluoroquinolones.

Antiarrhythmic Drugs: Relevance to Radiology

● In radiologic technology, they are important in preventing

infection during interventional procedures such as biopsies,

abscess drainage, or catheter insertion.

● Patients on long-term antibiotics may have altered gut flora

which can influence barium studies by changing bowel gas

patterns.

Antibacterial Drugs

● Antibiotics like Gentamicin can be nephrotoxic and may increase

the risk of kidney injury when combined with iodinated contrast

media.

● Technologists must ensure patients with renal compromise are

properly hydrated before contrast administration.

● Allergic reactions to antibiotics, especially Penicillin, can resemble

contrast reactions so careful history taking is necessary.

● Aseptic technique in handling catheters, needles, and contrast

syringes complements antibiotic protection and prevents

hospital-acquired infection.

Anticoagulants

prevent blood clot formation

Common Examples of: Anticoagulants

Heparin, Warfarin, and Enoxaparin

Coagulants

promote clotting when bleeding risk is high.

Common Examples of: Coagulants

Vitamin K and Protamine sulfate

Anticoagulant and Coagulant Drugs: Relevance to Radiology

● Radiologic relevance is strong in angiography and

vascular interventions where punctures are frequent.

● Anticoagulants increase the risk of prolonged bleeding

or hematoma at injection or catheter sites.

● Technologists must apply adequate pressure after venipuncture

and observe for bleeding.

● Contrast media does not directly interact with anticoagulants

but renal impairment from contrast can alter anticoagulant

metabolism, increasing bleeding risk.

● Patients on anticoagulants may have prolonged prothrombin

time; pre-procedure lab results must be verified.

● Coagulants may be administered in emergencies to reverse

excessive anticoagulation before procedures such as

image-guided biopsy.

Antidepressants

Antidepressants manage mood disorders and chronic anxiety that could affect cooperation during imaging.

Common Examples of: Antidepressants

Fluoxetine, Sertraline, Amitriptyline, and Venlafaxine.

Antidepressants: Relevance to Radiology

● Antidepressants manage mood disorders and chronic

anxiety that could affect cooperation during imaging.

● Examples include Fluoxetine, Sertraline, Amitriptyline, and

Venlafaxine.

● Some antidepressants alter blood pressure and heart

rhythm, relevant during cardiac or contrast procedures.

● Tricyclic antidepressants and MAO inhibitors can interact

with vasoconstrictor drugs such as epinephrine used in

contrast emergencies causing hypertensive crisis.

● These medications may increase sedation when combined

with anxiolytics or antihistamines given before procedures.

● Technologists should monitor vital signs and avoid giving

additional sedating agents without medical order.

● Antidepressants can cause tremors or restlessness that

mimic anxiety and interfere with steady positioning during

imaging.

● Awareness of these side effects helps technologists interpret

patient behavior accurately during exams.

Antiemetic Drugs

Antiemetics prevent nausea and vomiting related to anxiety, contrast injection, or motion sickness.

Common Examples of: Antiemetic Drugs

Ondansetron, Metoclopramide, and Promethazine.

Antiemetic Drugs: Relevance to Radiology

● Radiologic relevance is important in procedures involving

oral or rectal contrast such as barium studies or enterography.

● Vomiting during these procedures increases aspiration

risk and contaminates imaging equipment.

● Antiemetics help maintain patient comfort and reduce

interruptions during imaging.

● Some drugs like Metoclopramide accelerate gastric emptying which can alter timing for contrast transit studies.

● Sedative antiemetics such as Promethazine can enhance CNS depression when combined with anxiolytics or contrast

premedication.

● Technologists must ensure suction and emesis basins are

ready in case of breakthrough vomiting especially in sedated

patients.

Antihypertensive Drugs

● Antihypertensive agents reduce elevated blood pressure

to prevent cardiovascular complications during imaging.

● Major classes include Beta blockers, ACE inhibitors,

Calcium channel blockers, and ARBs.

Common Examples of: Antihypertensive Drugs

Metoprolol, Captopril, Amlodipine, Losartan

Antihypertensive Drugs: Relevance to Radiology

● Radiologic relevance is critical in cardiac stress testing

and interventional procedures where blood pressure

control prevents vessel rupture.

● Some antihypertensives such as Beta blockers slow the heart rate

which must be accounted for in CT cardiac gating.

● ACE inhibitors and ARBs may impair renal perfusion when

combined with iodinated contrast, increasing risk for

contrast-induced nephropathy.

● Patients should not abruptly stop antihypertensives before imaging since rebound hypertension can occur under procedural stress.

● Technologists should monitor vital signs closely and ensure

adequate hydration to protect renal function during contrast use.

Anti-inflammatory Drugs

● Anti-inflammatory drugs reduce tissue inflammation and pain.

two types of Anti-inflammatory Drugs

• Ibuprofen and corticosteroids such as Prednisone.

• These are non-steroidal (NSAIDs)

Anti-inflammatory Drugs: Relevance to Radiology

● In radiologic practice, corticosteroids are used as premedication for patients with known contrast allergy to suppress immune response.

● NSAIDs may compromise kidney perfusion which raises the

risk of contrast nephropathy especially in dehydrated or diabetic patients.

● Technologists should ensure the patient has no history of

renal dysfunction before administering iodinated contrast if

on long-term NSAIDs.

● Corticosteroids can weaken the immune system which

increases the risk of infection in interventional radiology.

● These drugs may also delay wound healing after

procedures.

● Monitoring of blood glucose is important since steroids can

induce hyperglycemia which affects contrast tolerance.

Antiseptic and Disinfectant Agents

Antiseptics and disinfectants destroy microorganisms and prevent infection.

Common Examples of: Antiseptics

Povidone-iodine and Chlorhexidine

Povidone-iodine and Chlorhexidine

used on patient skin before needle puncture.

Disinfectants 

Sodium hypochlorite and Alcohol

Sodium hypochlorite and Alcohol

used for cleaning equipment and surfaces.

Antiseptic and Disinfectant Agents: Relevance to Radiology

● Radiologic relevance is crucial in maintaining aseptic

technique during interventional procedures, catheter

insertions, or contrast injections.

● Use of proper antiseptic minimizes risk of infection from

invasive imaging.

● Povidone-iodine contains iodine which may cause allergic

reactions in patients sensitive to iodinated contrast.

● Alternative antiseptics like Chlorhexidine should be used

in such cases.

● Technologists must follow strict infection control protocols

and ensure no cross-contamination of imaging equipment.

Bronchodilators

Bronchodilators relax bronchial smooth muscles and improve airway patency

Common Examples of: Bronchodilators

Salbutamol, Terbutaline, and Ipratropium bromide.

Bronchodilators: Relevance to Radiology

● Radiologic relevance includes chest X-rays, CT scans, and MRI of patients with asthma or COPD who may experience

breathing difficulty.

● These drugs may be administered before procedures using

contrast media because contrast or anxiety can trigger

bronchospasm.

● They help ensure adequate lung expansion and improve image clarity.

● Overuse may cause palpitations, tremors, or transient

tachycardia which could affect ECG-gated imaging.

● Bronchodilators have no direct chemical interaction with

contrast media but their need indicates airway hyperreactivity

which raises the risk of allergic contrast reactions.

● Technologists should ensure availability of rescue inhalers and oxygen supply in imaging areas.

Cathartic

Cathartics promote bowel evacuation

antidiarrheal drugs

reduce intestinal motility.

Common Examples of: Cathartics

Bisacodyl or Magnesium

Bisacodyl or Magnesium

essential before barium enema or CT colonography to clear fecal matter for optimal visualization.

Inadequate bowel prep

results in retained feces that mimic pathology or obscure lesions.

Overuse of cathartics

can cause dehydration and electrolyte imbalance increasing risk of contrast nephropathy

Common Examples of: Antidiarrheal

Loperamide

Loperamide

used when imaging requires contrast retention in the intestines such as during small bowel follow-through.

Cathartic and Antidiarrheal Drugs: Relevance to Radiology

● These agents must be used cautiously since prolonged

use can delay contrast transit and distort diagnostic

timing.

● Radiologic technologists must confirm bowel

preparation compliance and hydration status before

examination.

Diuretics

Diuretics increase urine output by promoting renal excretion of sodium and water.

Common Examples of: Diuretics

Furosemide, Spironolactone, and Hydrochlorothiazide.

Diuretics: Relevance to Radiology

● Radiologic relevance includes renal studies and management of patients with heart failure or hypertension.

● Diuretics assist in evaluating kidney function by increasing urinary flow in functional imaging.

● They also prevent fluid overload after contrast injection in patients with cardiac compromise.

● However, excessive diuresis can cause dehydration and

reduce renal perfusion, worsening contrast-induced

nephropathy.

● Loop diuretics such as Furosemide can cause electrolyte

imbalance that triggers arrhythmia during procedures.

● Technologists must ensure the patient is hydrated before

contrast use and monitor urine output post-procedure.

Sedative and Hypnotic Drugs

● Sedatives reduce anxiety and induce calmness while hypnotics promote sleep or deep sedation.

Common Examples of: Sedative and Hypnotic Drugs

Midazolam, Diazepam, and Zolpidem

Sedative and Hypnotic Drugs: Relevance to Radiology

● Highly relevant in MRI, CT, and interventional imaging where

motion must be minimized.

● Facilitate pediatric and uncooperative patient imaging

without general anesthesia.

● Sedatives depress the central nervous system and can lower respiratory rate and blood pressure.

● When combined with contrast agents or opioids, they

increase risk of respiratory arrest.

● Patients must be continuously monitored for oxygen

saturation and cardiac activity.

● Contrast reactions may be masked in deeply sedated

patients because they cannot verbalize symptoms like

itching or chest tightness.

● Technologists should ensure emergency resuscitation

equipment is available before administration.

Vasodilators

expand blood vessels to improve circulation and reduce cardiac workload.

Common Examples of: Vasodilators

Nitroglycerin, Hydralazine, and Sodium nitroprusside.

Vasodilators: Relevance to Radiology

● Used in angiography and cardiac imaging to enhance

visualization of coronary arteries.

● Vasodilators can cause sudden hypotension especially when

combined with contrast which itself may induce vasodilation.

● Technologists must monitor blood pressure and be prepared for

dizziness or fainting

Vasoconstrictors

constrict blood vessels to elevate blood pressure or reduce bleeding.

Common Examples of: Vasoconstrictors

Epinephrine and Phenylephrine

Vasoconstrictors: Relevance to Radiology

● Used to manage severe hypotension or anaphylaxis triggered by

contrast injection.

● Epinephrine is the first-line emergency drug for severe allergic

contrast reactions because it reverses airway constriction and shock.

● Vasoconstrictors can increase heart rate and may provoke

arrhythmias when the patient is under stress or taking other

stimulants.

● Technologists must be trained in recognizing signs of anaphylaxis and

assist promptly under physician supervision.

Epinephrine

the first-line emergency drug for severe allergic contrast reactions because it reverses airway constriction and shock

Furosemide

Loop diuretics such as _____ can cause electrolyte imbalance that triggers arrhythmia during procedures.

Loop diuretics

powerful class of drugs that increase urine production by preventing the reabsorption of sodium, chloride, and potassium in the kidneys' thick ascending limb of the loop of Henle.

If allergic in Iodinated contrast, alternative antiseptic such as 

Chlorhexidine should be used in such cases

Promethazine

can enhance CNS depression when combined with anxiolytics or contrast premedication