Ondem
Ondem (Ondansetron 4 mg / 8 mg tablet) — selective 5-HT3 antagonist for chemo, radiation, post-operative, and severe gastroenteritis nausea. Alkem generic of Zofran.
✓ Lékařsky ověřeno Morgan Ellis — Pharmacy Researcher · 8 years experience Last reviewed: May 2026
⚡ Quick Answer — What is Ondem?
Ondem je film-coated tablet of ondansetron 4 mg / 8 mg, a selective serotonin 5-HT3 receptor antagonist. It is the most-used antiemetic worldwide and works against the strong serotonergic emetic stimulus generated by chemotherapy, radiation, surgery, gastroenteritis, and migraine. Manufactured by Alkem under WHO-GMP standards. Onset within 30 minutes orally and 8–12 hour duration; usually given 30–60 minutes before chemo or as needed for breakthrough nausea.
📦 Každá objednávka je pokryta naší Zárukou opětovného odeslání — pokud vaše zásilka nedorazí do 20 pracovních dnů, přeposíláme ji.
Proč objednávat z MedsBase
Naše generické léky pocházejí od výrobců certifikovaných WHO-GMP a jsou expedovány po celém světě v diskrétním, nenápadném balení – na vnější straně balíku není uveden název léku. Platby kartou jsou směrovány prostřednictvím regulovaného procesoru (popisky na výpisu zahrnují regulovaného procesora plateb kartou – nikdy “MedsBase” nebo název léku). Přijímáme také kryptoměny a bankovní převody SEPA. Každá objednávka je zajištěna naší politikou přeposlání.
When ondansetron is the right antiemetic
Ondansetron is the first-line antiemetic for serotonin-driven nausea — chemotherapy-induced nausea and vomiting (CINV), post-operative nausea and vomiting (PONV), radiation-induced nausea, and severe gastroenteritis. It is less useful for motion sickness and vestibular nausea (where the dominant pathway is histaminergic and cholinergic — promethazine/Avomine, cinnarizine, and meclozine work better) and not first-line for nausea-vomiting of pregnancy (NVP first-line is doxylamine + B6; ondansetron is reserved for refractory hyperemesis gravidarum after considering a small first-trimester cardiac/cleft-palate signal in observational studies).
Proč objednávat z MedsBase
Ondem is supplied from a výrobce certifikovaného WHO-GMP. Every order ships discreetly worldwide and is covered by our Zárukou opětovného odeslání — if it does not arrive within 20 business days, we reship at no cost. Ondansetron is the global standard for serotonin-driven emesis with millions of doses delivered safely each year. Film-coated tablet formulation is convenient when active vomiting prevents reliable swallowing.
Mechanismus účinku
Chemotherapy, radiation, and surgery damage gut enterochromaffin cells, which release massive amounts of serotonin (5-HT). The serotonin binds 5-HT3 receptors on vagal afferents and on the chemoreceptor trigger zone (area postrema), which signal the medullary vomiting centre. Ondansetron is a highly selective antagonist at the 5-HT3 receptor — it blocks this signal at both peripheral and central sites without affecting D2, H1, muscarinic, or alpha-adrenergic receptors. That selectivity explains its clean side-effect profile: minimal sedation, no extrapyramidal reactions, no anticholinergic burden.
Indikace
- CINV: moderately or highly emetogenic chemotherapy (cisplatin, anthracyclines, cyclophosphamide regimens) — usually with dexamethasone ± aprepitant for highly emetogenic regimens.
- Radiation-induced nausea: total body irradiation, high-dose abdominal radiation.
- Post-operative nausea and vomiting (PONV): single 4 mg dose at induction or end of surgery.
- Severe gastroenteritis: dehydration risk in children/adults.
- Migraine-associated nausea: often with sumatriptan or other triptans.
- Refractory hyperemesis gravidarum: after first-line doxylamine+B6 (Doxinate, Pregnidoxin NU) and metoclopramide have failed; specialist supervision recommended.
Dávka
| Indikace | Dávka |
|---|---|
| CINV (adult) | 8 mg 30 min before chemo, then 8 mg every 8–12 h for up to 5 days |
| PONV (adult) | 4 mg single dose, IV at induction or oral 1 h pre-op |
| Severe gastroenteritis (adult) | 4–8 mg every 8 h as needed (max 24 mg/day) |
| Paediatric (4–11 y, gastro) | 4 mg every 8 h (8–15 kg: 2 mg; 15–30 kg: 4 mg; >30 kg: 4–8 mg) |
| Severe hepatic impairment | Maximum 8 mg/day (Child-Pugh C) |
| Single-dose maximum | 16 mg IV; 24 mg oral — do not exceed |
Swallow whole with water. Onset 30–60 minutes; if vomiting prevents oral intake, an ODT (e.g. Ondem MD, Emeset 4 ODT) or injection (Ondem Injection) is more reliable.
Vedlejší účinky
- Common (> 10%): headache, constipation (the most clinically meaningful side effect — pre-empt with hydration and stool softener if multi-day course)
- Common (1–10%): mild flushing, fatigue, transient AST/ALT rise, dizziness, hot flushes after IV
- Méně časté: bradycardia, hypotension, myalgia
- Vzácné, ale závažné: QT prolongation/torsades, serotonin syndrome (with SSRIs/SNRIs/triptans/MAOIs), severe hypersensitivity, transient blindness (very rare, with rapid IV)
- Méně časté: extrapyramidal reactions (rare with ondansetron unlike older antiemetics)
Interakce léků
- Apomorphine: ABSOLUTE contraindication — severe hypotension and loss of consciousness reported.
- Other QT-prolonging drugs (azithromycin, clarithromycin, citalopram, escitalopram, methadone, amiodarone, sotalol, fluoroquinolones, hydroxychloroquine, antipsychotics): avoid combination or monitor ECG.
- Serotonergic drugs (SSRIs, SNRIs, MAOIs, triptans, tramadol, fentanyl, linezolid, methylene blue): rare serotonin syndrome reported — counsel patients to recognise tremor/agitation/clonus/hyperthermia.
- Tramadol: ondansetron may reduce tramadol analgesic effect (5-HT3 blockade interferes with descending pain inhibition).
- Strong CYP3A4 inducers (rifampicin, phenytoin, carbamazepine): can lower ondansetron levels and reduce efficacy.
Často kladené dotazy
How quickly does Ondem work?
Onset is 30–60 minutes. If you vomit within 30 minutes of swallowing the tablet, do not redose — switch to an ODT or injection if available.
Is Ondem safe in pregnancy?
Ondansetron is reserved for refractory hyperemesis gravidarum after doxylamine+B6 (Doxinate, Pregnidoxin NU), pyridoxine, and metoclopramide have failed. Some observational studies suggest a small first-trimester cardiac and cleft-palate signal; use should be discussed with a clinician.
Can I take Ondem for motion sickness?
Ondansetron works on the serotonin pathway and is not effective for motion sickness, which is histaminergic/cholinergic. Use promethazine (Avomine), cinnarizine, meclozine, or a hyoscine patch instead.
How is Ondem different from metoclopramide or domperidone?
Metoclopramide and domperidone are D2 antagonists — they speed gastric emptying and treat dyspepsia/regurgitation/gastroparesis nausea. Ondansetron is a 5-HT3 antagonist — better for chemo, radiation, surgery, severe gastroenteritis, and migraine nausea. Ondansetron is more expensive but cleaner (no extrapyramidal reactions, no hyperprolactinaemia).
Does Ondem cause drowsiness?
No. Unlike promethazine, prochlorperazine, and metoclopramide, ondansetron does not cause sedation or confusion and is preferred for ambulatory or driving patients.
What is the maximum dose?
Maximum single oral dose is 24 mg; maximum single IV dose is 16 mg (FDA cap). Total daily dose typically 24 mg/day; in severe hepatic impairment cap at 8 mg/day.
Can I take it with my SSRI antidepressant?
Short-term combinations are usually safe but counsel patients to recognise serotonin syndrome (tremor, agitation, hyperreflexia, clonus, fever). Long-term concurrent use is generally avoided when an alternative antiemetic is available.
Is constipation a problem?
Yes — ondansetron causes constipation in up to 1 in 10 users (more on multi-day chemo courses). Maintain hydration, fibre, and a stimulant laxative (senna/bisacodyl) prophylactically during chemo cycles.
Can Ondem be used in children?
Yes — weight-based dosing is well established for paediatric gastroenteritis (8–15 kg = 2 mg, 15–30 kg = 4 mg, >30 kg = 4–8 mg every 8 h). For active vomiting, an ODT or injection is more reliable than a tablet.
How is Ondem stored?
Store at room temperature (below 30°C), protect from light and moisture, keep out of reach of children. Tablets should remain in the original blister.
Other Nausea Treatments
- Ondem Injection (ondansetron 2 mg/ml IV/IM)
- Granicip (granisetron — longer-acting 5-HT3)
- Dompewal (domperidone — D2 antagonist for regurgitation)
- Stemetil MD (prochlorperazine ODT — vestibular nausea)
- Avomine (promethazine — motion sickness)
- Browse all Nausea Treatments
More options in Nausea Treatment
Řazeno podle nedávného objemu objednávek na MedsBase — co si ostatní zákazníci v této kategorii vybírají.
| Síla | 8 mg |
|---|---|
| Množství | 30 tablet/ks, 60 tablet/ks, 90 tablet/ks, 180 tablet/ks |
Ondem
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