Birth defects are common, costly, and critical conditions that affect 1 in every 33 babies born in the United States. Birth defects are structural changes present at birth that can affect almost any part or parts of the body such as the heart, brain, face, arms, and legs.
They may affect how the body looks, works, or both. Treating for Two works to understand trends in medicine use among pregnant women and women of reproductive age, and provide women and healthcare providers with information about the safety or risk of using specific medicines during pregnancy. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription over-the-counter medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital.
It is also important information to carry with you in case of emergencies. Ondansetron pronounced as on dan' se tron. Why is this medication prescribed? How should this medicine be used? Other uses for this medicine What special precautions should I follow? What special dietary instructions should I follow?
What should I do if I forget a dose? What side effects can this medication cause? What should I know about storage and disposal of this medication? Brand names. Do not chew the film. Other uses for this medicine. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT 3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema.
However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. In humans, urinary 5-hydroxyindoleacetic acid 5-HIAA excretion increases after cisplatin administration in parallel with the onset of emesis. The released serotonin may stimulate the vagal afferents through the 5-HT 3 receptors and initiate the vomiting reflex.
In healthy subjects, single intravenous doses of 0. Multiday administration of ondansetron has been shown to slow colonic transit in healthy subjects. Ondansetron has no effect on plasma-prolactin concentrations. QTc interval prolongation was studied in a double-blind, single-intravenous dose, placebo-and positive-controlled, crossover trial in 58 healthy subjects.
In this study, the 8 mg dose infused over 15 minutes did not prolong the QT interval to any clinically relevant extent. Ondansetron is absorbed from the gastrointestinal tract and undergoes some first-pass metabolism. Ondansetron systemic exposure does not increase proportionately to dose.
This may reflect some reduction of first-pass metabolism at higher oral doses. Circulating drug also distributes into erythrocytes. The metabolites are observed in the urine. The primary metabolic pathway is hydroxylation on the indole ring followed by subsequent glucuronide or sulfate conjugation. In terms of overall ondansetron turnover, CYP3A4 played the predominant role. Because of the multiplicity of metabolic enzymes capable of metabolizing ondansetron, it is likely that inhibition or loss of one enzyme e.
Although some nonconjugated metabolites have pharmacologic activity, these are not found in plasma at concentrations likely to significantly contribute to the biological activity of ondansetron. Age: Geriatric Population: A reduction in clearance and increase in elimination half-life are seen in patients older than 75 years compared to younger subjects [see Use in Specific Populations 8. Sex: Gender differences were shown in the disposition of ondansetron given as a single dose.
The extent and rate of absorption are greater in women than men. Slower clearance in women, a smaller apparent volume of distribution adjusted for weight , and higher absolute bioavailability resulted in higher plasma ondansetron concentrations. These higher plasma concentrations may in part be explained by differences in body weight between men and women. It is not known whether these sex-related differences were clinically important. More detailed pharmacokinetic information is contained in Tables 5 and 6.
The reduction in clearance was variable and not consistent with an increase in half-life [see Use in Specific Populations 8. Hepatic Impairment: In patients with mild-to-moderate hepatic impairment, clearance is reduced 2-fold and mean half-life is increased to In patients with severe hepatic impairment Child-Pugh score of 10 or greater , clearance is reduced 2-fold to 3-fold and apparent volume of distribution is increased with a resultant increase in half-life to 20 hours [see Dosage and Administration 2.
This resulted in a significant increase in the clearance of ondansetron. However, this increase is not thought to be clinically relevant [see Drug Interactions 7. Chemotherapeutic Agents: Carmustine, etoposide, and cisplatin do not affect the pharmacokinetics of ondansetron [see Drug Interactions 7.
Steroid administration was excluded from these clinical trials. The first or single dose was administered 30 minutes prior to chemotherapy. Each of the 3 treatment groups was shown to be statistically significantly superior to a historical placebo control. Dosage regimens of ondansetron 8 mg twice daily and 32 mg once daily are not recommended for the prevention of nausea and vomiting associated with highly emetogenic chemotherapy [see Dosage and Administration 2.
A randomized, placebo-controlled, double-blind trial was conducted in the US in 67 patients receiving a cyclophosphamide-based chemotherapy regimen containing doxorubicin. The first 8 mg dose of ondansetron was administered 30 minutes before the start of chemotherapy, with a subsequent dose 8 hours after the first dose, followed by 8 mg of ondansetron twice a day for 2 days after the completion of chemotherapy.
Ondansetron was significantly more effective than placebo in preventing vomiting. Treatment response was based on the total number of emetic episodes over the 3 day trial period. The results of this trial are summarized in Table In a double-blind, US trial in patients receiving a cyclophosphamide-based chemotherapy regimen containing either methotrexate or doxorubicin, ondansetron 8 mg administered twice a day, was as effective as ondansetron 8 mg administered 3 times a day in preventing nausea and vomiting.
See Table 8 for the details of the dosage regimens studied and results of this trial. In single-arm trials, patients receiving cyclophosphamide-based chemotherapy were re-treated with ondansetron 8 mg three times daily during subsequent chemotherapy for a total of re-treatment courses. Three open-label, single-arm, non-US trials have been performed with pediatric patients aged 4 to 18 years with cancer who were given a variety of cisplatin or noncisplatin regimens.
The initial dose of ondansetron injection ranged from 0. In 2 trials, the response rates to ondansetron 4 mg three times a day in patients younger than 12 years was similar to ondansetron 8 mg three times daily in patients 12 to 18 years. Prevention of emesis in these pediatric patients was essentially the same as for adults. In a randomized, placebo-controlled, double-blind trial in 20 patients, 8 mg of ondansetron administered 1.
Total body irradiation consisted of 11 fractions cGy per fraction over 4 days for a total of 1, cGy. Patients received 3 fractions for 3 days, then 2 fractions on Day 4. In an active-controlled, double-blind trial in patients receiving single high-dose radiotherapy to 1, cGy over an anterior or posterior field size of greater than or equal to 80 cm 2 to the abdomen, ondansetron was significantly more effective than metoclopramide with respect to complete control of emesis 0 emetic episodes.
Patients received the first dose of ondansetron 8 mg or metoclopramide 10 mg 1 to 2 hours before radiotherapy. If radiotherapy was given in the morning, 8 mg of ondansetron or 10 mg of metoclopramide was administered in the late afternoon and repeated again before bedtime. If radiotherapy was given in the afternoon, patients took 8 mg of ondansetron or 10 mg of metoclopramide only once before bedtime. Patients continued the doses of oral medication three times daily for 3 days. Wait at least 4 hours after ondansetron before you give the next dose, if you gave the dose late.
For example, suppose your child's dose times are 8 a. If you miss the 8 a. Then go back to the regular dose time. Give your child only one dose at a time. However, if your child vomits throws up less than 30 minutes after you gave a dose, you may give another dose. Side effects. What are the possible side effects of ondansetron? Call your child's contact nurse or doctor if your child has any of these signs or symptoms and they do not go away or they bother your child: headache dizziness constipation diarrhea loose, watery stools dry mouth feeling of warmth or flushing red face, body Call your child's doctor or nurse as soon as possible, during office hours, if your child has any of these signs: rash, hives raised, red, itchy areas on the skin or itching Most of the following side effects are not common, but they may be a sign of a serious problem.
Call your child's doctor right away or take your child to the Emergency Department if your child has any of these side effects: swelling of eyelids or face difficulty breathing chest pain, heart pounding or racing rapid or irregular heart rate , feeling faint. Safety measures. What safety measures should you take when your child is using ondansetron? It is important that you tell your doctor and pharmacist if your child takes any other medications, including: antiepileptic medicines, including carbamazepine and phenytoin heart medicines, including amiodarone and sotalol medicines used to treat mood disorders, including citalopram and sertraline antibiotics, such as clarithromycin antifungals, such as fluconazole or voriconazole cyclosporine , tacrolimus cisapride , domperidone Check with your child's doctor or pharmacist before giving your child any other medicines prescription, non-prescription, herbal or natural products.
Other important information. What other important information should you know about ondansetron? Other medicines may not work well with ondansetron. Check with your child's doctor or pharmacist before you give your child any other medicines, even medicines that you can buy without a doctor's order prescription. If you do not think that ondansetron is working for your child, talk to your child's doctor.
You may be asked to give a dose of ondansetron to your child before going to clinic. Give your child ondansetron 30 to 60 minutes before they are given chemotherapy. Disintegrating tablets contain aspartame. Children with phenylketonuria often called PKU should not receive aspartame. Disintegrating tablets contain gelatin.
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