1. Over the years literature has tend to ignore abnormal drug-radiopharmaceutical interactions
   1. Current review of literature define at least 250 different abnormal pharmaceutical interactions with some 40 different imaging procedures
   2. Part of the problem may be our failure to recognize that there is a problem
   3. Example - Patient has increased renal retension when undergoing a bone scan
      1. Would you recongize it?
      2. If so what could the problem be? Link to UAMS - Nuclear Pharmacy
2. Classification schemes for drug-radiopharmaceutical interactions
   1. The organ system involved
   2. Individual nonradioactive drug or its pharmacologic class
   3. Type of nuclear medicine study and/or the radiopharmaceutical
   4. Desirability of interaction
   5. Proposed mechanism (actual or theorized) for the interaction
   6. Note the organization at UAMS
3. Different types of drug-radiopharmaceutical interactions
   1. Pharmacologic interaction – interaction between a drug and a radiopharmaceutical occurs when either the intended and/or secondary physiologic or biologic effects of a therapeutic drug - altered biodistrbution of the radiotracer
   2. Toxicologic interaction – overextension of the usual therapeutic action of a drug and the resultant alteration in the biorouting of the radiotracer
   3. Pharmacokinetic interaction – the absorption, distribution, metabolism, or excretion of the drug will contribute to altering of the distribution of the radiotracer
   4. Pharmaceutical interaction – some physicochemical property of the drug interacts with some physiochemical property of the radiopharmaceutical
4. Altered biorouting maybe beneficial in nature Examples of drug-radiopharmaceutical interactions
   1. Thyroid studies and drugs that my effect uptake
   2. Possible effects of beta blockers and/or antimigraine medication on brain perfusion imaging
   3. Drugs that may alter bone imaging agents
   4. Drugs that effect liver/spleen imaging which include intrinsic lesions and/or colloid shift
   5. Drugs that alter ⁶⁷Gallium distribution
   6. Drugs that alter iminodiacetic acid in hepatobiliary imaging
   7. Drugs that effect ^99mTcMAA perfusion and ¹³³Xe ventilation distribution
   8. Drugs that may effect ²⁰¹Tl uptake
   9. Drugs that may alter ^99mTechnetium pyrophosphate for infarct analysis
   10. Drugs that may affect in vivo or in vitro labeling of RBCs with pertechnetate
   11. Drugs that may alter various functioning parameters in renal imaging
   12. Types of radioactive meals used to analyze gastric motility
   13. Drugs that may alter gastric motility

Please refer to the appropriate links for specfic "cause and effects" examples.

Material is a portion of a lecture presented by David L. Laven, NH, CRPh, FASHP, FAPPM. Drug-Radiopharmaceutical Interaction and Intervention with Diagnostic Imaging Procedures, Inservice Reviews for Nuclear Medicine Technology Volume 20, number 3.

Return to the Table of Content

10/17