Common Adjunctive Medications in General Nuclear Medicine (5–7,10,11,15–20,23)
| Drug | Indication | Dose | Pharmacokinetics | Mechanism of action | Contraindications/cautions | Adverse effects/interactions |
| Chloral hydrate | Sedation in children | 30–50 mg/kg to maximum of 1 g | Good gut absorption, rapid metabolism, and onset of action in 30–60 min; elimination half-life of 7–11 h and significant effects for 4–8 h | Prodrug; is converted to trichloroethanol, which modulates GABA to cause CNS depression | Contraindicated in significant liver, kidney, or cardiac dysfunction; caution in respiratory insufficiency and known hypersensitivity | Nausea, vomiting, diarrhea, dizziness, ataxia, drowsiness, headache, confusion, and paradoxic excitement; potential interactions with ethanol, warfarin, and CNS depressants |
| Diazepam (benzodiazepam) | Anxiolytic (claustrophobia) | 1–10 mg orally individualized by age and liver/kidney function | Onset, 15–45 min; peak 30–90 min; half-life 46 h; duration can be prolonged; 100% bioavailability orally; 98%–99% PPB; biphasic elimination with rapid component followed by slower half-life of 1–2 d | Causes inhibition through modulation of GABA and neuronal inhibition | Contraindicated in chronic obstructive pulmonary disease, severe liver or lung disease, sleep apnea, and hypersensitivity; caution in depression, dependence, glaucoma, liver or kidney dysfunction, depression, pregnancy, and lactation | Drowsiness, sedation, muscle weakness, ataxia, vertigo, headache, confusion, and paradoxic excitement, all with increased risk in the elderly; potential interactions with CNS depressants, including antihistamines and drugs metabolized by liver |
| Bisacodyl | Laxative for differentiating stool from disease | Single oral dose, 5–15 mg | Minimal absorption after oral administration; onset, 6–8 h | Stimulant laxative; increases stool water retention and peristalsis | Contraindicated in bowel obstruction; caution in liver impairment | Gastric irritation, cramping and fluid or electrolyte imbalance; potential interactions with medications that change gastric acidity |
| Heparin | Blood labeling to prevent clotting | 10–15 units/mL of blood being labeled in vitro | Highly plasma protein–bound with variable elimination based on dose (slow for low doses); rapid onset with effects lasting 3–6 h | Combines with antithrombin III to inactivate numerous clotting factors | Contraindicated in known sensitivity, acute bacterial endocarditis, and high bleeding risk; caution in anticoagulant use, asthma, liver dysfunction, and animal protein allergy | Bleeding, hemorrhage, and hypersensitivity; potential interaction with anticoagulants (including NSAIDs and aspirin) |
PPB = plasma protein bond; NSAIDs = nonsteroidal antiinflammatory drugs.
Duration is period of significant or measurable effect. Some adverse effects are more likely when used therapeutically than in single interventional doses.