Other Less Commonly Used Interventional Medications (5–7,10,11,15–20,23)
Drug | Indication | Dose | Pharmacokinetics | Mechanism of action | Contraindications/cautions | Adverse effects/interactions |
Acetazolamide | Cerebral flow reserve in brain perfusion studies | 1 g diluted in sterile water intravenously over 2 min | Onset, 30 min, slow; peak, 2 h; duration, 12 h; half-life, 3–6 h; 70%–90% plasma protein–bound | Carbonic anhydrase inhibitor; causes sodium bicarbonate dieresis and vasodilation in brain in response to cerebral carbonic acidosis (carbon dioxide clearance inhibition) | Contraindicated in sodium or potassium depletion, hyperchloremic acidosis, Addison disease, closed-angle glaucoma, and severe renal or liver dysfunction; caution in acute stroke, kidney or liver disease, diabetes, gout, lupus, hypotension, and pregnancy | Tingling sensation, flushing, dizziness, blurred vision, confusion, nausea, headache, tinnitus, and allergic reaction; potential interactions with aspirin, lithium, cyclosporin, amphetamines, other diuretics, antihypertensives, salicylates, hypoglycemics, phenytoin, sodium bicarbonate, anticoagulants, and cardiac glycosides |
Cimetidine | Enhanced detection of Meckel diverticulum | 300 mg orally, 4 times over 24 h in adults and 20 mg/kg in 20 mL of saline intravenously over 20 min in children | Onset, 0.5–1 h; peak, 1 h; half-life, 2 h; duration, 4–6 h; 20% plasma protein–bound | H2 histamine receptor blocker; reduces gastric acid secretion and volume and impedes 99mTc-pertechnetate secretion | Contraindicated in known hypersensitivity; caution in renal or cardiovascular dysfunction | Headache, dizziness, diarrhea, muscle pain, confusion, and bradycardia; potential interactions with medications metabolized in liver; can also alter bioavailability of drugs reliant on stomach pH for absorption |
Ranitidine | As above | 300 mg orally for adults and 1 mg/kg intravenously over 20 min for children | Onset, 60 min; peak, 2–3 h; half-life, 2–3 h; duration, 4–13 h; 15% plasma protein–bound | As above | As above | As above |
Omeprazole | 40 mg orally morning before and morning of scan | Onset, 60 min; peak, 2 h; half-life, 0.5 h; duration, 3–5 d; 95% plasma protein–bound | Proton pump inhibitor (irreversible); suppresses stomach acid secretion and impedes 99mTc-pertechnetate secretion | Contraindicated in known hypersensitivity; caution in liver dysfunction; ranitidine is preferred in pediatrics | Infrequent but include headache, dizziness, abdominal pain, diarrhea, nausea, vomiting, and rash; potential interactions with diazepam, phenytoin, warfarin, and medications reliant on gastric acidity for absorption |
Duration is period of significant or measurable effect. Some adverse effects are more likely when used therapeutically than in single interventional doses.