Omnipaque

ADVERSE REACTIONS—Intrathecal The most frequently reported adverse reactions with OMNIPAQUE are headache, backache, neckache and stiffness, nausea, and vomiting. These reactions usually occur 1 to 10 hours after injection, and almost all occur within 24 hours. They usually last for a few hours, and usually disappear within 24 hours. Severe headaches persisting for days have been reported. Headache is often accompanied by nausea and vomiting and tends to be more frequent and persistent in patients not optimally hydrated. Transient alterations in vital signs may occur and their significance must be assessed on an individual basis. Those reactions reported in clinical studies with OMNIPAQUE are listed below in decreasing order of occurrence, based on clinical studies of 1531 patients. Headaches: The most frequently occurring adverse reaction following myelography has been headache, with an incidence of approximately 18%. Headache may be caused by either a direct effect of the contrast medium or by CSF leakage at the dural puncture site. However, in managing the patient , it is considered more important to minimize intracranial entry of contrast medium by postural management than attempting to control possible CSF leakage (see PATIENT MANAGEMENT ). Pain: Backache, neckache and stiffness, and neuralgia occurred following injection with an incidence of about 8%. Nausea and Vomiting: Nausea was reported with an incidence of about 6%, and vomiting about 3% (see PATIENT MANAGEMENT ). Maintaining normal hydration is very important. The use of phenothiazine antinauseants is not recommended. (See WARNINGS—General .) Reassurance to the patient that the nausea will clear usually is all that is required. Dizziness: Transient dizziness was reported in about 2% of the patients. Other Reactions: Other reactions occurring with an individual incidence of less than 0.1% included: feeling of heaviness, hypotension, hypertonia, sensation of heat, sweating, vertigo, loss of appetite, drowsiness, hypertension, photophobia, tinnitus, neuralgia, paresthesia, difficulty in micturition, and neurological changes. General Adverse Reactions to Contrast Media Physicians should remain alert for the occurrence of adverse effects in addition to those discussed above, particularly the following reactions which have been reported in the literature for nonionic, water-soluble myelographic media including iohexol. These have included, but are not limited to, convulsion, aseptic and bacterial meningitis, and CNS and other neurological disturbances. An aseptic meningitis syndrome has been reported (in less than 0.01%). It was usually preceded by pronounced headaches, nausea and vomiting. Onset usually occurred about 12 to 18 hours postprocedure. Prominent features were meningismus, fever, sometimes with oculomotor signs and mental confusion. Lumbar puncture revealed a high white cell count, high protein content often with a low glucose level and with absence of organisms. The condition usually started to clear spontaneously about 10 hours after onset, with complete recovery over 2 to 3 days. Allergy or Idiosyncrasy: Chills, fever, profuse diaphoresis, pruritus, urticaria, nasal congestion, dyspnea, anaphylactic reactions, anaphylactic shock, and a case of Guillain-Barré syndrome. CNS Irritation: Transient perceptual aberrations such as hallucinations, depersonalization, amnesia, hostility, amblyopia, diplopia, photophobia, psychosis, insomnia, anxiety, depression, hyperesthesia, visual or auditory or speech disturbances, confusion and disorientation. In addition, malaise, weakness, convulsion, EEG changes, meningism, hyperreflexia or areflexia, hypertonia or flaccidity, hemiplegia, paralysis, quadriplegia, restlessness, tremor, echoacousia, echolalia, asterixis, cerebral hemorrhage, and dysphasia have occurred. Profound mental disturbances have also been reported. They consisted of various forms and degrees of aphasia, mental confusion, or disorientation. The onset is usually at 8 to 10 hours and lasts for about 24 hours, without aftereffects. Apprehension, agitation, or progressive withdrawal in several instances to the point of somnolence, stupor, and coma have been reported, as well as transitory hearing loss or other auditory symptoms and visual disturbances, including unilateral or bilateral loss of vision which may last for hours. In one case, persistent cortical loss of vision has been reported in association with convulsions. Ventricular block has been reported; amnesia of varying degrees may be present for the reaction event. Persistent though transitory weakness in the leg or ocular muscles has been reported. Peripheral neuropathies have been reported. They include sensory and/or motor or nerve root disturbances, myelitis, persistent leg muscle pain or weakness, 6th nerve palsy, or cauda equina syndrome. Muscle cramps, fasciculation or myoclonia, spinal convulsion, or spasticity responded promptly to a small intravenous dose of diazepam. In general, the reactions which are known to occur upon parenteral administration of iodinated contrast agents are possible with any nonionic agent. Severe, life-threatening, fatal anaphylactic shock has been reported. Adverse reactions to injectable contrast media fall into two categories: chemotoxic reactions and idiosyncratic reactions. Chemotoxic reactions result from the physicochemical properties of the contrast media, the dose, and speed of injection. All hemodynamic disturbances and injuries to organs or vessels perfused by the contrast medium are included in this category. Idiosyncratic reactions include all other reactions. They occur more frequently in patients 20 to 40 years old. Idiosyncratic reactions may or may not be dependent on the amount of dose injected, the speed of injection, and the radiographic procedure. Idiosyncratic reactions are subdivided into minor, intermediate, and severe. The minor reactions are self-limited and of short duration; the severe reactions are life-threatening and treatment is urgent and mandatory. The reported incidence of adverse reactions to contrast media in patients with a history of allergy is twice that of the general population. Patients with a history of previous reactions to a contrast medium are three times more susceptible than other patients. However, sensitivity to contrast media does not appear to increase with repeated examinations. Most adverse reactions to injectable contrast media appear within 1 to 3 minutes after the start of injection, but delayed reactions may occur.

CONTRAINDICATIONS—Intrathecal OMNIPAQUE should not be administered to patients with a known hypersensitivity to iohexol. Myelography should not be performed in the presence of significant local or systemic infection where bacteremia is likely. Intrathecal administration of corticosteroids with OMNIPAQUE is contraindicated. Because of the possibility of overdosage, immediate repeat myelography in the event of technical failure is contraindicated (see DOSAGE AND ADMINISTRATION ).

DESCRIPTION Iohexol, N , N´ - Bis(2,3-dihydroxypropyl)-5-[ N -(2,3-dihydroxypropyl)-acetamido]-2,4,6-triiodoisophthalamide, is a nonionic, water-soluble radiographic contrast medium with a molecular weight of 821.14 (iodine content 46.36%). In aqueous solution each triiodinated molecule remains undissociated. The chemical structure is: OMNIPAQUE is provided as a sterile, pyrogen-free, colorless to pale-yellow solution, in Pharmacy Bulk Package, in the following iodine concentrations: 300 and 350 mg Iodine/mL. A Pharmacy Bulk Package is used to dispense multiple single doses, utilizing a suitable transfer device. OMNIPAQUE 300 contains 647 mg of iohexol equivalent to 300 mg of organic iodine per mL; and OMNIPAQUE 350 contains 755 mg of iohexol equivalent to 350 mg of organic iodine per mL. Each milliliter of iohexol solution contains 1.21 mg tromethamine and 0.1 mg edetate calcium disodium with the pH adjusted between 6.8 and 7.7 with hydrochloric acid or sodium hydroxide. All solutions are sterilized by autoclaving and contain no preservatives. Iohexol solution is sensitive to light and therefore should be protected from exposure. The available concentrations have the following physical properties: Concentration (mg Iodine/mL) Osmolality By vapor-pressure osmometry. (mOsm/kg water) Osmolarity (mOsm/L) Absolute Viscosity (cp) Specific Gravity 20°C 37°C 37°C 300 672 465 11.8 6.3 1.349 350 844 541 20.4 10.4 1.406 OMNIPAQUE 300 and OMNIPAQUE 350 have osmolalities from approximately 2.2 to 3 times that of plasma (285 mOsm/kg water) or cerebrospinal fluid (301 mOsm/kg water) as shown in the above table and are hypertonic under conditions of use. Chemical Structure

DOSAGE AND ADMINISTRATION — Intrathecal The volume and concentration of OMNIPAQUE 300 to be administered will depend on the degree and extent of contrast required in the area(s) under examination and on the equipment and technique employed. OMNIPAQUE 300 at a concentration of 300 mg Iodine/mL is recommended for the examination of the lumbar, thoracic, and cervical regions in adults by lumbar or direct cervical injection and is slightly hypertonic to CSF. A total dose of 3060 mg iodine or a concentration of 300 mg Iodine/mL should not be exceeded in adults in a single myelographic examination. This is based on clinical trial evaluation to date. As in all diagnostic procedures, the minimum volume and dose to produce adequate visualization should be used. Most procedures do not require either maximum dose or concentration. Anesthesia is not necessary. Premedication sedatives or tranquilizers are usually not needed (see PRECAUTIONS ). Patients should be well hydrated prior to and following contrast administration. Seizure-prone patients should be maintained on anticonvulsant medication. Many radiopaque contrast agents are incompatible in vitro with some antihistamines and many other drugs; therefore, concurrent drugs should not be physically admixed with contrast agents. Rate of Injection To avoid excessive mixing with CSF and consequent dilution of contrast, injection should be made slowly over 1 to 2 minutes. Depending on the estimated volume of contrast medium which may be required for the procedure a small amount of CSF may be removed to minimize distention of the subarachnoid spaces. The lumbar or cervical puncture needle may be removed immediately following injection since it is not necessary to remove OMNIPAQUE after injection into the subarachnoid space. Adults The usual recommended total doses for use in lumbar, thoracic, cervical, and total columnar myelography in adults are 1.2 g Iodine to 3 g Iodine as follows: Procedure Formulations Concentration (mg Iodine/mL) Volume (mL) Dose (g Iodine) Thoracic Myelography (via lumbar injection) OMNIPAQUE 300 300 6-10 1.8-3.0 Cervical Myelography (via lumbar injection) OMNIPAQUE 300 300 6-10 1.8-3.0 Cervical Myelography (via C1-2 injection) OMNIPAQUE 300 300 4-10 1.2-3.0 Total Columnar Myelography (via lumbar injection) OMNIPAQUE 300 300 6-10 1.8-3.0 Refer to DIRECTIONS FOR PROPER USE OF OMNIPAQUE PHARMACY BULK PACKAGE section for instructions. Parenteral products should be inspected visually for particulate matter or discoloration prior to administration. If particulate matter or discoloration is present, do not use. Repeat Procedures If in the clinical judgment of the physician sequential or repeat examinations are required, a suitable interval of time between administrations should be observed to allow for normal clearance of the drug from the body. An interval of at least 48 hours should be allowed before repeat examination; however, whenever possible, 5 to 7 days is recommended.

INDICATIONS AND USAGE—Intrathecal OMNIPAQUE 300 is indicated for intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography).

WARNINGS—General SEVERE ADVERSE EVENTS - INADVERTENT INTRATHECAL ADMINISTRATION Serious adverse reactions have been reported due to the inadvertent intrathecal administration of iodinated contrast media that are not indicated for intrathecal use. These serious adverse reactions include: death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema. Special attention must be given to ensure that OMNIPAQUE 350 is not administered intrathecally. (OMNIPAQUE 300 is approved for intrathecal administration). If grossly bloody CSF is encountered, the possible benefits of a myelographic procedure should be considered in terms of the risk to the patient. Caution is advised in patients with a history of epilepsy, severe cardiovascular disease, chronic alcoholism, or multiple sclerosis. Elderly patients may present a greater risk following myelography. The need for the procedure in these patients should be evaluated carefully. Special attention must be paid to dose and concentration of the medium, hydration, and technique used. Patients who are receiving anticonvulsants should be maintained on this therapy. Should a seizure occur, intravenous diazepam or phenobarbital sodium is recommended. In patients with a history of seizure activity who are not on anticonvulsant therapy, premedication with barbiturates should be considered. Prophylactic anticonvulsant treatment with barbiturates should be considered in patients with evidence of inadvertent intracranial entry of a large or concentrated bolus of the contrast medium since there may be an increased risk of seizure in such cases. Drugs which lower the seizure threshold, especially phenothiazine derivatives, including those used for their antihistamine properties, are not recommended for use with OMNIPAQUE. Drugs which lower the seizure thresh old, especially phenothiazine derivatives, including those used for their antihistamine properties, are not recommended for use with OMNIPAQUE. Others include MAO inhibitors, tricyclic antidepressants, CNS stimulants, and psychoactive drugs described as analeptics, major tranquilizers, or antipsychotic drugs. While the contributory role of these medications has not been established, the use of such drugs should be based on physician evaluation of potential benefits and potential risks. Physicians have discontinued these agents at least 48 hours before and for at least 24 hours postprocedure. Care is required in patient management to prevent inadvertent intracranial entry of a large dose or concentrated bolus of the medium. Also, effort should be directed to avoid rapid dispersion of the medium causing inadvertent rise to intracranial levels (eg, by active patient movement). Direct intracisternal or ventricular administration for standard radiography (not CT) is not recommended. In most reported cases of major motor seizures with nonionic myelographic media, one or more of the following factors were present. Therefore avoid: Deviations from recommended procedure or in myelographic management. Use in patients with a history of epilepsy. Overdosage. Intracranial entry of a bolus or premature diffusion of a high concentration of the medium. Medication with neuroleptic drugs or phenothiazine antinauseants. Failure to maintain elevation of the head during the procedure, on the stretcher, or in bed. Excessive and particularly active patient movement or straining.

OVERDOSAGE Clinical consequences of overdosage with OMNIPAQUE have not been reported. However, based on experience with other nonionic myelographic media, physicians should be alert to a potential increase in frequency and severity of CNS-mediated reactions. Even use of a recommended dose can produce effects tantamount to overdosage, if incorrect management of the patient during or immediately following the procedure permits inadvertent early intracranial entry of a large portion of the medium. The intracisternal LD 50 value of OMNIPAQUE (in grams of iodine per kilogram body weight) is greater than 2 in mice.

Drug Interactions Drugs which lower seizure threshold, especially phenothiazine derivatives including those used for their antihistaminic or antinauseant properties, are not recommended for use with OMNIPAQUE. Others include monoamine oxidase (MAO) inhibitors, tricyclic antidepressants, CNS stimulants, psychoactive drugs described as analeptics, major tranquilizers, or antipsychotic drugs. Such medications should be discontinued at least 48 hours before myelography, should not be used for the control of nausea or vomiting during or after myelography, and should not be resumed for at least 24 hours postprocedure. In nonelective procedures in patients on these drugs, consider prophylactic use of anticonvulsants.

Drug/Laboratory Test Interaction If iodine-containing isotopes are to be administered for the diagnosis of thyroid disease, the iodine-binding capacity of thyroid tissue may be reduced for up to 2 weeks after contrast medium administration. Thyroid function tests which do not depend on iodine estimation, eg, T 3 resin uptake or direct thyroxine assays, are not affected. Many radiopaque contrast agents are incompatible in vitro with some antihistamines and many other drugs; therefore, no other pharmaceuticals should be admixed with contrast agents.

CLINICAL PHARMACOLOGY—Intrathecal Iohexol is absorbed from cerebrospinal fluid (CSF) into the bloodstream and is eliminated by renal excretion. No significant metabolism, deiodination, or biotransformation occurs. The initial concentration and volume of the medium, in conjunction with appropriate patient manipulation and the volume of CSF into which the medium is placed, will determine the extent of the diagnostic contrast that can be achieved. Following intrathecal injection in conventional radiography, OMNIPAQUE 300 will continue to provide good diagnostic contrast for at least 30 minutes. Slow diffusion of iohexol takes place throughout the CSF with subsequent absorption into the bloodstream. Once in the systemic circulation, iohexol displays little tendency to bind to serum or plasma proteins. At approximately 1 hour following injection, contrast of diagnostic quality will no longer be available for conventional myelography. If computerized tomographic (CT) myelography is to follow, consideration should be given to a delay of several hours to allow the degree of contrast to decrease. After administration into the lumbar subarachnoid space, computerized tomography shows the presence of contrast medium in the thoracic region in about 1 hour, in the cervical region in about 2 hours, and in the basal cisterns in 3 to 4 hours. In patients with renal impairment, depending on the degree of impairment, prolonged plasma iohexol levels may be anticipated due to decreased renal elimination.

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Omnipaque Iohexol Iohexol Iohexol Iodine Tromethamine Edetate calcium disodium Hydrochloric acid Sodium hydroxide colorless to pale yellow Omnipaque Iohexol Iohexol Iohexol Iodine Tromethamine Edetate calcium disodium Hydrochloric acid Sodium hydroxide colorless to pale yellow

Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term animal studies have not been performed with OMNIPAQUE to evaluate carcinogenic potential. OMNIPAQUE was not genotoxic in a series of studies, including the Ames test, the mouse lymphoma TK locus forward mutation assay, and a mouse micronucleus assay. OMNIPAQUE did not impair the fertility of male or female rats when administered at dosages up to 4 g Iodine/kg (2.3 times the maximum recommended dose for a 50 kg human, or approximately 0.4 times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates.)

NDA020608

Omnipaque

Iohexol

0407-1413

HUMAN PRESCRIPTION DRUG

INTRATHECAL,INTRAVASCULAR,INTRAVENOUS,ORAL,RECTAL

PRINCIPAL DISPLAY PANEL - 300 mg Bottle Box Label NDC 0407-1413-68 GE Healthcare Y-538B Contains 10 x 500 mL Bottles OMNIPAQUE™ (iohexol) Injection 300 mg Iodine/mL PHARMACY BULK PACKAGE Not for Direct Infusion For Injection or Oral Use Sterile Aqueous Solution PRINCIPAL DISPLAY PANEL - 300 mg Bottle Box Label

PHARMACY BULK PACKAGE–NOT FOR DIRECT INFUSION Section I — Intrathecal Section II — Intravascular Section III — Oral/Body Cavity Use 350 NOT FOR INTRATHECAL USE

Information for Patients (or if applicable, parents of pediatric patients) Patients receiving injectable radiopaque diagnostic agents should be instructed to: Inform your physician if you are pregnant (see CLINICAL PHARMACOLOGY ). Inform your physician if you are diabetic or if you have multiple myeloma, pheochromocytoma, homozygous sickle cell disease or known thyroid disorder (see WARNINGS ). Inform your physician if you are allergic to any drugs, food, or if you had any reactions to previous injections of dyes used for x-ray procedures (see PRECAUTIONS—General ). Inform your physician about any other medications you are currently taking, including non-prescription drugs, before you are administered this drug.

Nursing Mothers It is not known to what extent iohexol is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women. Bottle feedings may be substituted for breast feedings for 24 hours following administration of OMNIPAQUE.

Pediatric Use Pediatric patients at higher risk of experiencing adverse events during contrast medium administration may include those having asthma, a sensitivity to medication and/or allergens, congestive heart failure, a serum creatinine greater than 1.5 mg/dL or those less than 12 months of age.

Pregnancy Teratogenic Effects Pregnancy Category B Reproduction studies performed in rats and rabbits at dosages up to 4 g Iodine/kg and 2.5 g Iodine/kg, respectively [2.3 and 1.4 times the maximum recommended dose for a 50 kg human, or approximately 0.4 (rat) and 0.5 (rabbit) times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates] have not revealed evidence of impaired fertility or harm to the fetus due to OMNIPAQUE. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Teratogenic Effects Pregnancy Category B Reproduction studies performed in rats and rabbits at dosages up to 4 g Iodine/kg and 2.5 g Iodine/kg, respectively [2.3 and 1.4 times the maximum recommended dose for a 50 kg human, or approximately 0.4 (rat) and 0.5 (rabbit) times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates] have not revealed evidence of impaired fertility or harm to the fetus due to OMNIPAQUE. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

HOW SUPPLIED OMNIPAQUE 300 500 mL in + PLUS PAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages (NDC 0407-1413-68) OMNIPAQUE 350 500 mL in + PLUS PAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages (NDC 0407-1414-98) Protect polymer bottles of OMNIPAQUE from strong daylight and direct exposure to sunlight. Do not freeze. OMNIPAQUE should be stored at controlled room temperature, 20°-25°C (68°- 77°F); excursions permitted to 15°-30°C (59°-86°F) [see USP Controlled Room Temperature]. OMNIPAQUE Injection in all presentations may be stored in a contrast media warmer for up to one month at 37°C (98.6°F). SPECIAL HANDLING AND STORAGE FOR POLYMER BOTTLES ONLY: DO NOT USE IF TAMPER-EVIDENT RING IS BROKEN OR MISSING.

Protect polymer bottles of OMNIPAQUE from strong daylight and direct exposure to sunlight. Do not freeze. OMNIPAQUE should be stored at controlled room temperature, 20°-25°C (68°- 77°F); excursions permitted to 15°-30°C (59°-86°F) [see USP Controlled Room Temperature]. OMNIPAQUE Injection in all presentations may be stored in a contrast media warmer for up to one month at 37°C (98.6°F). SPECIAL HANDLING AND STORAGE FOR POLYMER BOTTLES ONLY: DO NOT USE IF TAMPER-EVIDENT RING IS BROKEN OR MISSING.

PRECAUTIONS—General Diagnostic procedures which involve the use of radiopaque diagnostic agents should be carried out under the direction of personnel with the prerequisite training and with a thorough knowledge of the particular procedure to be performed. Appropriate facilities should be available for coping with any complication of the procedure, as well as for emergency treatment of severe reactions to the contrast agent itself. After parenteral administration of a radiopaque agent, competent personnel and emergency facilities should be available for at least 30 to 60 minutes since severe delayed reactions have occurred. (See ADVERSE REACTIONS .) Preparatory dehydration is dangerous and may contribute to acute renal failure in patients with advanced vascular disease, diabetic patients, and in susceptible nondiabetic patients (often elderly with preexisting renal disease). Dehydration in these patients seems to be enhanced by the osmotic diuretic action of contrast agents. Patients should be well hydrated prior to and following administration of any contrast medium, including iohexol. The possibility of a reaction, including serious, life-threatening, fatal, anaphylactoid, cardiovascular or central nervous system reactions, should always be considered (see ADVERSE REACTIONS ). Therefore, it is of utmost importance that a course of action be carefully planned in advance for the immediate treatment of serious reactions, and that adequate and appropriate facilities and personnel be readily available in case of any reaction. The possibility of an idiosyncratic reaction in susceptible patients should always be considered (see ADVERSE REACTIONS ). The susceptible population includes, but is not limited to, patients with a history of a previous reaction to contrast media, patients with a known sensitivity to iodine per se, and patients with a known clinical hypersensitivity: bronchial asthma, hay fever, and food allergies. The occurrence of severe idiosyncratic reactions has prompted the use of several pretesting methods. However, pretesting cannot be relied upon to predict severe reactions and may itself be hazardous for the patient. It is suggested that a thorough medical history with emphasis on allergy and hypersensitivity, prior to the injection of any contrast media, may be more accurate than pretesting in predicting potential adverse reactions. A positive history of allergies or hypersensitivity does not arbitrarily contraindicate the use of a contrast agent where a diagnostic procedure is thought essential, but caution should be exercised (see ADVERSE REACTIONS ). Premedication with antihistamines or corticosteroids these patients should be considered. Pretreatment does not prevent serious life-threatening reactions, but may reduce both their incidence and severity. In patients with severe renal insufficiency or failure, compensatory biliary excretion of the drug is anticipated to occur, with a slow clearance into the bile. Patients with hepatorenal insufficiency should not be examined unless the possibility of benefit clearly outweighs the additional risk. Administration of contrast media should be performed by qualified personnel familiar with the procedure and appropriate patient management (see PATIENT MANAGEMENT ). Sterile technique must be used with any spinal puncture. If nondisposable equipment is used, scrupulous care should be taken to prevent residual contamination with traces of cleansing agents. Parenteral products should be inspected visually for particulate matter and discoloration prior to administration. If particulate matter or discoloration is present, do not use. Repeat Procedures If in the clinical judgment of the physician sequential or repeat examinations are required, a suitable interval of time between administrations should be observed to allow for normal clearance of the drug from the body (see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY ). Information for Patients (or if applicable, parents of pediatric patients) Patients receiving injectable radiopaque diagnostic agents should be instructed to: Inform your physician if you are pregnant (see CLINICAL PHARMACOLOGY ). Inform your physician if you are diabetic or if you have multiple myeloma, pheochromocytoma, homozygous sickle cell disease or known thyroid disorder (see WARNINGS ). Inform your physician if you are allergic to any drugs, food, or if you had any reactions to previous injections of dyes used for x-ray procedures (see PRECAUTIONS—General ). Inform your physician about any other medications you are currently taking, including non-prescription drugs, before you are administered this drug. Drug Interactions Drugs which lower seizure threshold, especially phenothiazine derivatives including those used for their antihistaminic or antinauseant properties, are not recommended for use with OMNIPAQUE. Others include monoamine oxidase (MAO) inhibitors, tricyclic antidepressants, CNS stimulants, psychoactive drugs described as analeptics, major tranquilizers, or antipsychotic drugs. Such medications should be discontinued at least 48 hours before myelography, should not be used for the control of nausea or vomiting during or after myelography, and should not be resumed for at least 24 hours postprocedure. In nonelective procedures in patients on these drugs, consider prophylactic use of anticonvulsants. Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term animal studies have not been performed with OMNIPAQUE to evaluate carcinogenic potential. OMNIPAQUE was not genotoxic in a series of studies, including the Ames test, the mouse lymphoma TK locus forward mutation assay, and a mouse micronucleus assay. OMNIPAQUE did not impair the fertility of male or female rats when administered at dosages up to 4 g Iodine/kg (2.3 times the maximum recommended dose for a 50 kg human, or approximately 0.4 times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates.) Pregnancy Teratogenic Effects Pregnancy Category B Reproduction studies performed in rats and rabbits at dosages up to 4 g Iodine/kg and 2.5 g Iodine/kg, respectively [2.3 and 1.4 times the maximum recommended dose for a 50 kg human, or approximately 0.4 (rat) and 0.5 (rabbit) times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates] have not revealed evidence of impaired fertility or harm to the fetus due to OMNIPAQUE. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Nursing Mothers It is not known to what extent iohexol is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women. Bottle feedings may be substituted for breast feedings for 24 hours following administration of OMNIPAQUE. Pediatric Use Pediatric patients at higher risk of experiencing adverse events during contrast medium administration may include those having asthma, a sensitivity to medication and/or allergens, congestive heart failure, a serum creatinine greater than 1.5 mg/dL or those less than 12 months of age.