TIGAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TIGAN (TIGAN).
TIGAN (trimethobenzamide) acts on the chemoreceptor trigger zone (CTZ) to inhibit emetic stimuli, primarily through antagonism of dopamine D2 receptors, though its exact mechanism is not fully elucidated.
| Metabolism | Trimethobenzamide is metabolized in the liver via conjugation and oxidation, with the involvement of cytochrome P450 enzymes. |
| Excretion | Renal (30-50% as unchanged drug and metabolites), biliary/fecal (minor). |
| Half-life | 12-15 hours; may be prolonged in hepatic impairment. |
| Protein binding | Approximately 90% bound to plasma proteins. |
| Volume of Distribution | 3-5 L/kg; indicates extensive tissue distribution. |
| Bioavailability | PO: 60-70%; IM: 100%; Rectal: approximately 50-60%. |
| Onset of Action | IM: 20-30 minutes; IV: 5-10 minutes; PO: 30-60 minutes; Rectal: 30-60 minutes. |
| Duration of Action | 4-6 hours via IM/IV; 3-4 hours PO/rectal; may persist longer with hepatic dysfunction. |
Adults: 200 mg IM or 100 mg PO or 200 mg PR every 6–8 hours as needed.
| Dosage form | CAPSULE |
| Renal impairment | GFR 10–50 mL/min: administer 75% of normal dose; GFR <10 mL/min: administer 50% of normal dose. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use. |
| Pediatric use | Children >14 kg: 15–20 mg/kg/day IM/PO/PR in divided doses every 6–8 hours; maximum 400 mg/day. <14 kg: 10 mg/kg/day. |
| Geriatric use | Initiate at lower end of dosing range (e.g., 100 mg PO/PR or 100 mg IM every 8–12 hours) due to increased sensitivity; avoid in severe hepatic impairment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TIGAN (TIGAN).
| Breastfeeding | It is not known whether trimethobenzamide is excreted in human milk. M/P ratio is not reported. Caution is advised due to the potential for adverse effects in nursing infants, such as sedation or anticholinergic effects. A decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. |
| Teratogenic Risk | TIGAN (trimethobenzamide) is classified as FDA Pregnancy Category C. Animal studies have shown embryotoxic and teratogenic effects at doses 1.5–3 times the human dose. There are no adequate and well-controlled studies in pregnant women. First trimester: Potential risk of fetal harm; use only if clearly needed. Second and third trimesters: Limited data; avoid use near term due to potential for maternal hypotension and fetal hypoxia. |
■ FDA Black Box Warning
There is no FDA black box warning for TIGAN.
| Serious Effects |
["Hypersensitivity to trimethobenzamide or any component of the formulation","Children with viral illness"]
| Precautions | ["May cause drowsiness and dizziness","Use with caution in patients with a history of seizures","Avoid in pediatric patients with viral illnesses due to risk of Reye's syndrome-like symptoms","May impair ability to drive or operate machinery","Use in elderly may increase risk of extrapyramidal symptoms"] |
Loading safety data…
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and signs of extrapyramidal symptoms or sedation. In late pregnancy, assess fetal heart rate due to potential maternal hypotension leading to reduced placental perfusion. No specific fetal monitoring is required beyond standard prenatal care unless maternal adverse effects occur. |
| Fertility Effects | No specific studies on human fertility with trimethobenzamide. In animal studies, no adverse effects on fertility were observed at therapeutic doses. However, antiemetics may impact prolactin levels, which could theoretically affect ovulation; clinical significance is unknown. |