McKenna's Drug Handbook for Nursing & Midwifery, 7e

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.

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.

tetrofosmin Myoview Pregnancy risk category NR Use in sport: Permitted Available form Powder for injection: 0.23 mg/10 mL