Tomohexol

Uses

SECTION I- INTRATHECAL

Tomohexol 180, Tomohexol 240, and Tomohexol 300 are used for intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography). Tomohexol 180 is used for intrathecal administration in children including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography(myelography, cisternography).

SECTION II- INTRAVASCULAR

Tomohexol 350 is used for adults for angiocardiography (ventriculography, selective coronary arteriography), aortography including studies of the aortic root, aortic arch, ascending aorta, abdominal aorta and its branches, contrast enhancement for computed tomographic head and body imaging, intravenous digital subtraction angiography of the head, neck, abdominal, renal and peripheral vessels, peripheral arteriography, and excretory urography.

Tomohexol 350 is used for children for angiocardiography (ventriculography, pulmonary arteriography, and venography; studies of the collateral arteries and aortography, including the aortic root, aortic arch, ascending and descending aorta).

Tomohexol 300 is used for adults for aortography including studies of the aortic arch, abdominal aorta and its branches, contrast enhancement for computed tomographic head and body imaging, cerebral arteriography, peripheral venography (phlebography), and excretory urography.

Tomohexol 300 is used for children for angiocardiography (ventriculography), excretory urography, and contrast enhancement for computed tomographic head imaging.

Tomohexol 240 is used for adults for contrast enhancement for computed tomographic head imaging and peripheral venography (phlebography).

Tomohexol 140 is used for adults for intra-arterial digital subtraction angiography of the head, neck, abdominal, renal and peripheral vessels.

Tomohexol 240 is used for children for contrast enhancement for computed tomographic head imaging.

SECTION III - ORAL/BODY CAVITY USE

Tomohexol 240, Tomohexol 300, and Tomohexol 350 have osmolalities from approximately 1.8 to 3.0 times that of plasma (285 mOsm/kg water) and are hypertonic under conditions of use.

Adults: Tomohexol 350 is used for adults for arthrography and oral pass-thru examination of the gastrointestinal tract.

Tomohexol 300 is used for adults for arthrography and hysterosalpingography. Tomohexol 240 is used for adults for arthrography, endoscopic retrograde pancreatography and cholangiopancreatography, herniography, and hysterosalpingography. Tomohexol diluted to concentrations from 6 mgI/mL to 9 mgI/mL administered orally in conjunction with Tomohexol 300 at a concentration of 300 mgI/mL administered intravenously is used for adults for contrast enhanced computed tomography of the abdomen.

Children: Tomohexol 300 is used for children for examination of the gastrointestinal tract.

Tomohexol 240 is used for children for examination of the gastrointestinal tract.

Tomohexol 180 is used for children for examination of the gastrointestinal tract.

Tomohexol diluted to concentrations from 50 mgI/mL to 100 mgI/mL is used for children for voiding cystourethrography.

Tomohexol diluted to concentrations from 9 mgI/mL to 21 mgI/mL administered orally in conjunction with Tomohexol 240 at a concentration of 240 mgI/mL or Tomohexol 300 at a concentration of 300 mgI/mL administered intravenously is used for children for use in contrast enhanced computed tomography of the abdomen.

How Tomohexol works

Organic iodine compounds block x-rays as they pass through the body, thereby allowing body structures containing iodine to be delineated in contrast to those structures that do not contain iodine. The degree of opacity produced by these compounds is directly proportional to the total amount (concentration and volume) of the iodinated contrast agent in the path of the x-rays. After intrathecal administration into the subarachnoid space, diffusion of iohexol in the CSF allows the visualization of the subarachnoid spaces of the head and spinal canal. After intravascular administration, iohexol makes opaque those vessels in its path of flow, allowing visualization of the internal structures until significant hemodilution occurs.

Dosage

Tomohexol dosage

Injection As iohexol soln containing 6-350 mg iodine/mL: Dose and strength used depends on the procedure and route of administration.

Injection-

Angiocardiography:

• Adult:Ventriculography: 350 mg iodine/ml: 30-60 ml, usual: 40 ml, may be repeated as necessary. If with selective coronary arteriography: max 250 ml. Selective coronary arteriography: 350 mg iodine/ml: 3-14 ml per inj, usual: 5 ml. Aortic root and arch study when used alone: 350 mg iodine/ml: 20-75 ml, usual 50 ml. Multiple procedures: 350 mg iodine/ml: max 250 ml.
• Child:Ventriculography: 350 mg iodine/ml: 1-1.5 ml/kg, usual: 1.25 ml/kg; 300 mg iodine/ml: 1.5-2 ml/kg, usual 1.75 ml/kg. Max: 5 ml/kg; 350 mg iodine/ml: 250 ml; 300 mg iodine/ml: 291 ml. Pulmonary angiography: 350 mg iodine/ml: 1 ml/kg. Multiple procedures: Max: 5 ml/kg; 350 mg iodine/ml: 250 ml; 300 mg iodine/ml: 291 ml.

Aortography and selective visceral arteriography

• Adult:Use 300 or 350 mg iodine/ml solution, single inj. Aorta: 50-80 ml; major branches: 30-60 ml; renal arteries: 5-15 ml. Repeat as necessary. Max: 300 mg iodine/ml: 291 ml; 350 mg iodine/ml: 250 ml.
• Child:Use 350 mg iodine/ml solution: 1 ml/kg, single dose. Max: 5 ml/kg up to 250 ml.

Voiding cystourethrography:

• Adult:Use diluted solutions using sterile water for inj to concentrations of 50-100 mg iodine/ml. Usual volume: 50 mg iodine/ml solution: 50-600 ml; 100 mg iodine/ml: 50-300 ml.
• Child:Children: Use diluted solutions using sterile water for inj to concentrations of 50-100 mg iodine/ml: 50-300 ml.

Hysterosalpingography:

• Adult:240 mg iodine/ml: 15-20 ml; 300 mg iodine/ml: 15-20 ml.

Arthrography:

• Adult:Knee: 240 mg iodine/ml: 5-15 ml; 300 mg iodine/ml: 5-15 ml; 350 mg iodine/ml: 5-10 ml. Shoulder: 240 mg iodine/ml: 3 ml; 300 mg iodine/ml: 10 ml. Temporomandibular: 300 mg iodine/ml: 0.5-1 ml. Lower volumes are recommended for double-contrast examinations; higher volumes are recommended fro single-contrast examinations.

Herniography:

• Adult:240 mg iodine/ml: 50 ml.

Excretory urography:

• Adult:Use 300 or 350 mg iodine/ml solution: 200-350 mg iodine/kg.
• Child:Use 300 mg iodine/ml solution: 0.5-3 ml/kg, usual: 1-1.5 ml/kg; max: 3 ml/kg.

Endoscopic retrograde cholangiopancreatography (ERCP), Endoscopic retrograde pancreatography (ERP):

• Adult:Use 240 mg iodine/ml: 10-50 ml.

Intra-arterial-

Peripheral arteriography:

• Adult:Aortofemoral runoffs: 350 mg iodine/ml: 20-70 ml; 300 mg iodine/ml: 30-90 ml. Selective arteriograms (femoral/iliac): 350 mg iodine/ml: 10-30 ml; 300 mg iodine/ml: 10-60 ml. Venography (per leg): 240 mg iodine/ml: 20-150 ml; 300 mg iodine/ml: 40-100 ml.

Cerebral arteriography:

• Adult:Use 300 mg iodine/ml solution: Common carotid artery: 6-12 ml; internal carotid artery: 8-10 ml; external carotid artery: 6-9 ml; vertebral artery: 6-10 ml.

Digital subtraction angiography:

• Adult:Use 140 mg iodine/ml solution: Aorta: 20-45 ml at 8-20 ml/sec; carotid: 5-10 ml at 3-6 ml/sec; femoral: 9-20 ml at 3-6 ml/sec; vertebral: 4-10 ml at 2-8 ml/sec; renal: 6-12 ml at 3-6 ml/sec; other branches of the aorta (includes subclavian, axillary, innominate and iliac): 8-25 ml at 3-10 ml/sec.

Intrathecal-

Contrast-enhanced computerized tomography:

• Adult:Lumbar (via lumbar inj): 180 mg iodine/ml: 10-17 ml; 240 mg iodine/ml: 7-12.5 ml. Thoracic (via lumbar or cervical inj): 240 mg iodine/ml: 6-12.5 ml; 300 mg iodine/ml: 6-10 ml. Cervical (via lumbar inj): 240 mg iodine/ml: 6-12.5 ml; 300 mg iodine/ml solution: 6-10 ml. Cervical (via C1-2 inj): 180 mg iodine/ml: 7-10 ml; 240 mg iodine/ml: 6-12.5 ml; 300 mg iodine/ml: 4-10 ml. Total columnar (via lumbar inj): 240 mg iodine/ml: 6-12.5 ml; 300 mg iodine/ml: 6-10 ml.
• Child:Use 180 mg iodine/ml solution. 0-<3 mth: 240 ml; 3-<36 mth: 4-8 ml; 3-<7 yr: 5-10 ml; 7-<13 yr: 5-12 ml; 13-18 yr: 6-15 ml.

Intravenous-

Contrast-enhanced computerized tomography of the abdomen:

• Adult:In conjunction with dilute oral admin, use 300 mg iodine/ml solution: 100-150 ml. The oral dose is administered 20-40 min prior to IV dose and image acquisition.
• Child:In conjunction with dilute oral admin, use 240 or 300 mg iodine/ml solution: 1-2 ml/kg; max 3 ml/kg. The oral dose is administered 30-60 min prior to IV dose and image acquisition.

Digital subtraction angiography:

• Adult:350 mg iodine/ml: 30-50 ml, as a bolus at 7.5-30 ml/second using a pressure injector, usually for 3 or more inj; max: 250 ml.

Contrast-enhanced computerized tomography:

• Adult:Head imaging by inj: 300 mg iodine/ml: 70-150 ml; 350 mg iodine/ml: 80 ml. Head imaging by infusion: 240 mg iodine/ml: 120-250 ml. Body imaging by inj: 300 mg iodine/ml: 50-200 ml; 350 mg iodine/ml: 60-100 ml.
• Child:Head imaging: 240 or 300 mg iodine/ml: 1-2 ml/kg. Max: 28 g iodine with 240 mg iodine/ml solution or 35 g iodine with 300 mg iodine/ml solution.

Dose and strength used depends on the procedure and route of administration.

Side Effects

Flushing or a sensation of heat; pain, extravasation, thrombophlebitis at the inj site; nausea, vomiting, headache, and dizziness; urticaria, pruritus, pallor, sweating, metallic taste, weakness, coughing, rhinitis, sneezing, lachrymation, visual disturbances; hypotension, tachycardia, bradycardia, transient ECG abnormalities, haemodynamic disturbances; dyspnoea, bronchospasm, angioedema, severe urticaria; convulsions, paraesthesia, paralysis; acute renal failure; thromboembolism, disseminated intravascular coagulation, thrombocytopenia; hyperthyroidism, thyroid storm thyrotoxicosis.

Toxicity

Non-ionic radiocontrast agents like iohexol are cytotoxic to renal cells. The toxic effects include apoptosis, cellular energy failure, disruption of calcium homeostasis, and disturbance of tubular cell polarity, and are thought to be linked to oxidative stress.

Precaution

Asthma or a history of allergies (risk of anaphylactoid reactions is increased); compromised blood-brain barrier (severe neurotoxicity after intrathecal use); epilepsy and brain tumour (higher risk of convulsions); severe hepatic or renal impairment, diabetics with renal impairment, dehydration and others who may be at increased risk of renal failure; multiple myeloma (dehydration from use may cause precipitation of protein in the renal tubules, leading to anuria and fatal renal failure); severe hypertension; advanced cardiac disease; phaeochromocytoma; sickle-cell disease; hyperthyroidism; debilitated, severely ill, very old, or very young patients; occlusive vascular disease. Special care to ensure that 140 and 350 mg iodine/ml solutions are not given intrathecally. Adequate resuscitative facilities should be available when radiographic procedures are undertaken, and patients should be kept under observation for a suitable period after the procedure.

Food Interaction

Tomohexol Drug Interaction

Major: dexamethasone, dexamethasoneUnknown: aspirin, aspirin, charcoal, charcoal, dextran, low molecular weight, dextran, low molecular weight, sodium iodide, sodium iodide, acetaminophen, acetaminophen, valproic acid, valproic acid, cyanocobalamin, cyanocobalamin, pyridoxine, pyridoxine, phytonadione, phytonadione

Tomohexol Disease Interaction

Moderate: myasthenia gravis, asthma/allergies

Volume of Distribution

• 350-849 mL/kg

Elimination Route

Small amounts are absorbed through the bladder via intravesical instillation. Following intrauterine instillation, the majority of the medium within the uterine cavity is discharged into the vagina immediately upon termination of procedure. However, any medium retained in the uterine or peritoneal cavity is absorbed systemically within 60 minutes. May not be absorbed for up to 24 hours if tubes are obstructed and dilated.

Half Life

Intrathecal half-life is 3.4 hours (mean). Intravascular is approximately 2 hours (with normal renal function).

Clearance

• 109 mL/min [Adult patients receiving 16-18 ml of iohexol (180 mgI/mL) by lumbar intrathecal injection]

Elimination Route

Tomohexol is absorbed from cerebrospinal fluid (CSF) into the bloodstream and is eliminated by renal excretion. No significant metabolism, deiodination, or biotransformation occurs.

Pregnancy & Breastfeeding use

Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Contraindication

Procedure-specific. Intrathecal: Myelography in significant local or systemic infection where bacteremia is likely; concurrent use with corticosteroids; repeat myelography in the event of technical failure (risk of overdosage). Hysterosalpingography: During menstrual period or when menstrual flow in imminent; presence of infection; pregnancy, 6 mth after termination of pregnancy or 30 days after conization or curettage.

Acute Overdose

Preclinical data indicate a high safety margin for Tomohexol and no fixed upper dose level has been established for routine intravascular use. Symptomatic overdosing is unlikely in patients with normal renal function unless the patient has received an excess of 2000 mg I/kg body-weight over a limited period of time. The duration of the procedure is important for the renal tolerability of high doses of contrast media (t½ ~ 2 hours). Accidental overdosing is most likely following complex angiographic procedures in children, particularly when multiple injections of contrast medium with high-concentration are given. In cases of overdose, any resulting water or electrolyte imbalance must be corrected. Renal function should be monitored for the next 3 days. If needed, haemodialysis may be used for clearance of excessive contrast medium. There is no specific antidote.

Storage Condition

Store at 20-25° C. Protect from light. Do not freeze.

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