Dosage should be adjusted according to the indication for therapy, severity of symptoms and the response of the patient.<br/>CAPSULES , 300 mg:<br/>Usual Adult Dosage: One 300 mg capsule t.i.d. or q.i.d.<br/>INJECTABLE, 100 mg/mL (not for use in children):<br/>Usual Adult Dosage: 2 mL (200 mg) t.i.d. or q.i.d. intramuscularly. NOTE: The injectable form is intended for intramuscular administration only; it is not recommended for intravenous use. Intramuscular administration may cause pain, stinging, burning, redness and swelling at the site of injection. Such effects may be minimized by deep injection into the upper outer quadrant of the gluteal region, and by avoiding the escape of solution along the route.
Chemically, trimethobenzamide HCl is N-[p -[2-(dimethylamino)ethoxy]benzyl]-3,4,5- trimethoxybenzamide monohydrochloride. It has a molecular weight of 424.93 and the following structural formula: Capsules: Each 300-mg Tigan capsule for oral use contains trimethobenzamide hydrochloride equivalent to 300 mg. The capsule has an opaque purple cap marked���Tigan���and an opaque purple body marked���M079���. Inactive Ingredients: D&C Red No. 28, FD&C Blue No.1, lactose, magnesium stearate, starch and titanium dioxide. Single-Dose Vials: Each 2-mL single-dose vial contains 200 mg trimethobenzamide hydrochloride compounded with 1 mg sodium citrate and 0.4 mg citric acid as buffers and pH adjusted to approximately 5.0 with sodium hydroxide. Multi-Dose Vials: Each mL contains 100 mg trimethobenzamide hydrochloride compounded with 0.45% phenol as preservative, 0.5 mg sodium citrate and 0.2 mg citric acid as buffers and pH adjusted to approximately 5.0 with sodium hydroxide.
Mechanism of Action: The mechanism of action of Tigan as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited. In dogs pretreated with trimethobenzamide HCl, the emetic response to apomorphine is inhibited, while little or no protection is afforded against emesis induced by intragastric copper sulfate.<br/>Pharmacokinetics: The pharmacokinetics of trimethobenzamide have been studied in healthy adult subjects. Following administration of 200 mg (100 mg/mL) Tigan I.M. injection, the time to reach maximum plasma concentration (T) was about half an hour, about 15 minutes longer for Tigan 300 mg oral capsule than an I.M. injection. A single dose of Tigan 300 mg oral capsule provided a plasma concentration pro���le of trimethobenzamide similar to Tigan 200 mg I.M. The relative bioavailability of the capsule formulation compared to the solution is 100%. The mean elimination half-life of trimethobenzamide is 7 to 9 hours.<br/>Special Populations:<br/>Gender: Systemic exposure to trimethobenzamide was similar between men (N=40) and women (N=28).<br/>Race: Pharmacokinetics appeared to be similar for Caucasians (N=53) and African Americans (N=12).
Use of the injectable form of Tigan in children and use of any dosage form in patients with known hypersensitivity to trimethobenzamide are contraindicated.
Capsules, 300 mg trimethobenzamide hydrochloride each, bottles of 100 NDC 61570-079-01 300 mg 100's Single-Dose Vials, 2 mL, trays of 25 NDC 61570-543-25 100 mg/mL in 2 mL Single-Dose Vials Multi-Dose Vials, 20 mL NDC 61570-541-20 100 mg/mL in 20 mL Multi-Dose Vials Prescribing Information as of November 2005. Distributed By: Monarch Pharmaceuticals, Inc., Bristol, TN 37620 Manufactured By: King Pharmaceuticals, Inc., Bristol, TN 37620
General: During the course of acute febrile illness, encephalitides, gastroenteritis, dehydration and electrolyte imbalance, especially in children and the elderly or debilitated, CNS reactions such as opisthotonos, convulsions, coma and extrapyramidal symptoms have been reported with and without use of Tigan (trimethobenzamide hydrochloride) or other antiemetic agents. In such disorders caution should be exercised in administering Tigan, particularly to patients who have recently received other CNS-acting agents (phenothiazines, barbiturates, belladonna derivatives). Primary emphasis should be directed toward the restoration of body���uids and electrolyte balance, the relief of fever and relief of the causative disease process. Overhydration should be avoided since it may result in cerebral edema. The antiemetic effects of Tigan may render diagnosis more dif���cult in such conditions as appendicitis and obscure signs of toxicity due to overdosage of other drugs.
There have been reports of hypersensitivity reactions and Parkinson-like symptoms. There have been instances of hypotension reported following parenteral administration to surgical patients. There have been reports of blood dyscrasias, blurring of vision, coma, convulsions, depression of mood, diarrhea, disorientation, dizziness, drowsiness, headache, jaundice, muscle cramps and opisthotonos. If these occur, the administration of the drug should be discontinued. Allergic-type skin reactions have been observed; therefore, the drug should be discontinued at the���rst sign of sensitization. While these symptoms will usually disappear spontaneously, symptomatic treatment may be indicated in some cases.
Caution should be exercised when administering Tigan to children for the treatment of vomiting. Antiemetics are not recommended for treatment of uncomplicated vomiting in children and their use should be limited to prolonged vomiting of known etiology. There are two principal reasons for caution: Tigan may produce drowsiness. Patients should not operate motor vehicles or other dangerous machinery until their individual responses have been determined.<br/>Usage in Pregnancy:: Trimethobenzamide hydrochloride was studied in reproduction experiments in rats and rabbits and no teratogenicity was suggested. The only effects observed were an increased percentage of embryonic resorptions or stillborn pups in rats administered 20 mg and 100 mg/kg and increased resorptions in rabbits receiving 100 mg/kg. In each study these adverse effects were attributed to one or two dams. The relevance to humans is not known. Since there is no adequate experience in pregnant or lactating women who have received this drug, safety in pregnancy or in nursing mothers has not been established.<br/>Usage with Alcohol:: Concomitant use of alcohol with Tigan may result in an adverse drug interaction.
Tigan is indicated for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis.