Special Warning : אזהרת שימוש

4.4.      Special warnings and precautions for use
•      Allergic reaction is possible regardless of the administration route and dose.
•      The intolerance risk is not univocal in the case of medicinal products administered locally for opacification of bodily cavities: a) Administration by certain specific routes (articular, biliary, intrathecal, intrauterine, etc.) leads to considerable systemic passage: systemic effects may therefore be observed.
b) Administration by oral or rectal route generally leads to very limited systemic diffusion; if the gastro- intestinal mucosa is normal, only 5% maximum of the dose administered is found in the urine, the remainder being eliminated in the faeces. However, if the gastro-intestinal mucosa is altered, absorption is increased; it becomes total and rapid in the event of perforation, with passage into the cavity of the peritoneum. The medicinal product is then eliminated in the urine. The occurrence of any dose-dependent systemic effects therefore depends on the condition of the gastro-intestinal mucosa.
c) The immuno-allergic mechanism is however not dose-dependent and always likely to be observed, regardless of the administration route.
With respect to the prevalence and the intensity of adverse effects, the following therefore are antagonists:
• Medicinal products administered by vascular route and by certain local routes
• Medicinal products administered by intestinal route and little absorbed under normal conditions 
4.4.1. Special warnings

4.4.1.1. Hypersenstivity
Any iodinated contrast medium may cause minor or major reactions that may be life-threatening. They may be immediate (less than 60 minutes) or delayed (up to 7 days). They are often unpredictable.
The risk of major reaction requires the immediate availability of the means necessary for emergency resuscitation.
Several mechanisms have been reported:
• Direct toxicity affecting the vascular endothelium and tissue proteins.
• Pharmacological action altering the concentration of certain endogenous factors (histamine, complement fractions, inflammation mediators), more frequent with hyperosmolar products.
• Immediate IgE-type allergy dependent on the TELEBRIX GASTRO contrast medium(300 mg Iodine/mL), solution for oral or rectal administration (anaphylaxis)
• Cell-mediated allergic reactions (late onset cutaneous reactions) Patients having previously suffered a reaction during administration of an iodinated contrast medium are at increased risk of experiencing a renewed reaction during administration of the same, or another iodinated contrast medium, and are therefore considered to be high risk subjects.

4.4.1.2. Iodinated contrast media and the thyroid (see 4.4.2.5. Precautions for use - Dysthyroidism)
Prior to administration of an iodinated contrast medium, it must be ensured that the patient is not to undergo a scintigraphic exploration of the thyroid, or administration of radioactive iodine treatment.

Administration of iodinated contrast media, regardless of the route, disturbs hormone assays and iodine fixation by the thyroid or thyroid cancer metastases until normalisation of urine iodine levels.

4.4.2. Precautions for use

4.4.2.1. Intolerance to iodinated contrast media:
Prior to the examination:
• Identify subjects at risk via specific questioning concerning history.
Corticosteroids and H1-antihistamines were suggested as premedication in patients at the highest risk of hypersensitivity reaction. However, they do not prevent serious or fatal anaphylactic shock to occur.

During the examination, the following must be ensured:
     Medical supervision.
     Maintenance of a venous access.
     necessary resuscitation equipment at hand.
After the examination:
•   Further to administration of a contrast medium, the patient must remain under observation for at least 30 minutes, as most adverse effects occur within this time.
•   The patient must be warned that late onset reactions may occur (up to 7 days later) (see section 4.8 – Undesirable effects).

4.4.2.2. Renal failure
Iodinated contrast media may temporarily alter renal function or aggravate existing renal failure. The preventive measures to be taken are as follows:
• Identify high risk patients: dehydrated subjects, patients with renal failure, diabetes, severe heart failure, monoclonal gammapathy (multiple myeloma, Waldenström’s disease) recent myocardial infarction, intra-aortic balloon pump, low haematocrit, hyperuricaemia, or a history of renal failure following administration of iodinated contrast media, children under one year and atheromatous elderly subjects or with polymorbidity syndrome.
•   Initiate appropriate hydration by fluid and sodium solution where required.
•   Avoid combinations of nephrotoxic medicines (if such combinations are necessary, reinforce renal biological monitoring). The medicinal products in question are notably angiotensin-converting enzyme (ACE) inhibitors, aminoglycosides, organoplatins, high-dose methotrexate, pentamidine, foscarnet and certain antivirals (aciclovir, ganciclovir, valaciclovir, adefovir, cidofovir, and tenofovir), vancomycin, amphotericin B, non-steroidal anti-inflammatory drugs, diuretics, immunosuppressants such as ciclosporine or tacrolimus, ifosfamide.
•   Since renal elimination is reduced in the presence of renal dysfunction, the interval between two X- ray examinations involving injection of an iodinated contrast medium must be as long as clinically acceptable, especially in risk patients. For these patients, allow for a 48- to 72-hour interval. In the event of renal failure following the first examination, any further examination should be deferred until after initial renal function has been restored.
Haemodialysis patients may receive iodinated contrast media as these products are dialysable. The haemodialysis department must first be consulted.
4.4.2.3. Liver failure
Special attention must be paid when a patient suffers both from liver failure and renal failure, as this situation increases the risk of contrast medium retention.
4.4.2.4. Asthma
Asthma must be stabilized prior to injection of an iodinated contrast medium.
Special attention must be paid in cases of asthma attacks occurring 8 days prior to the examination, due to the increased risk of bronchospasm.

4.4.2.5. Dysthyroidism
Following injection of an iodinated contrast medium, in particular in patients with goitre or with a history of dysthyroidism, the risk of hyperthyroidism or induction of hypothyroidism also exists. Hypothyroidism may also occur in newborns that have received, or whose mother has received an iodinated contrast medium. Their thyroid function should be therefore evaluated and monitored.
4.4.2.6. Severe cardiovascular disease
In the event of existing or early stage heart failure, coronary artery disease, pulmonary arterial hypertension or valvular heart disease, the risk of pulmonary oedema, myocardial ischemia and arrhythmia or severe hemodynamic disorders is increased following administration of an iodinated contrast medium.
4.4.2.7. Central nervous system disorders
The benefit/risk ratio must be estimated on a case per case basis due to the risk of worsening of neurological symptoms in patients presenting with transient ischemic attack, acute cerebral infarction, recent intracranial haemorrhage, cerebral oedema, idiopathic or secondary epilepsy (tumour, scar).
4.4.2.8. Myasthenia
Administration of a contrast medium may worsen myasthenia symptoms.
4.4.2.9. Enhanced side effects
Side effects related to administration of iodinated contrast media may be enhanced by pronounced states of excitation, anxiety and pain. Appropriate treatment, and possibly sedation, may be necessary 
4.4.2.10 Warnings concerning excipients
This medicinal product contains low amounts of ethanol (alcohol), up to 0.52 mL for 100 mL.

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