Diagnostic preparations 1313
Interactions
Drug-drug.
Anticonvulsantsandpsychoactive
drugs, hormone preparations, corticosteroids,
cyproheptadine, antithyroid agents:
May
influence test results. Monitor closely.
Paracetamol:
Metyrapone may potentiate
paracetamoltoxicity.Usecautiouslytogether.
Contraindications
Contraindicated in individuals with known
hypersensitivity to the preparation and in
those with adrenocortical insufficiency.
care considerations
• Monitor vital signs closely following
procedure.
• Drugs affecting pituitary or adrenocortical
function should be discontinued before the
metyrapone test.
• Metyraponemay trigger transient adreno
cortical insufficiency in individuals with
severely compromised adrenocortical
or anterior pituitary. This can be rapidly
corrected by giving appropriate doses of
corticosteroids.
• Individuals with liver cirrhosis respond to
metyrapone test more slowly.
Patient teaching
• Instruct person to take the capsules with
milk or yoghurt after a meal.
• Advise person to report any adverse
effects.
• Advise person to take care when standing
up or getting out of bed due to potential
dizziness.
• Caution person that delayed effects may
impact on safety when driving or operating
machinery.
tetrofosmin
Myoview
Pregnancy risk category NR
Use in sport: Permitted
Available form
Powder for injection:
0.23 mg/10 mL
Indications & dosages
➤
Adjunct in diagnosis of ischaemic heart
disease—
Adults:
185–250 MBq IV at peak exercise,
followed by 500–750 MBq IV at rest approx
imately 4 hours afterwards. Imaging may
begin 15 minutes following administration.
Action
Diagnostic radiopharmaceutical for cardio
vascular system imaging. Half-life 6 hours.
Route Onset
Peak Duration
IV 15 mins (at stress), Unknown 4 hrs
30 mins (at rest)
Adverse reactions
CNS:
dizziness, headache, feeling of body
warmth.
CV:
hypotension,
torsades des pointes
.
ENT:
altered sense of smell.
EYE:
abnormal vision.
GI:
mild burning sensation in mouth,
nausea, transient metallic taste, vomiting.
Haematological:
slightWBCcountelevation.
Respiratory:
dyspnoea.
Skin:
erythema, urticaria, flushing, urticaria.
Other:
anaphylaxis
, facial oedema, fever,
hypersensitivity reaction, oedema.
Interactions
Drug-drug.
Drugs that influencemyocardial
function and/or blood flow (beta blockers,
calcium channel blockers, nitrates):
May
cause false positive test results. Monitor
cardiac function closely.
Contraindications
Contraindicated in individuals with known
hypersensitivity to tetrofosmin or other
component in the preparation, and in
women who are pregnant.
care considerations
•
Alert:
Radioactive drug—drug must be
handled with care and appropriate safety
measures should be used to minimise
radiation exposure to the person and to
staff.
