Fargan is a phenothiazine derivative first-generation H 1 receptor antagonist but is also an antagonist at muscarinic (M1) and dopamine (D2) receptors. Adverse effects associated with therapeutic use of Fargan include dystonic reactions, psychosis in the absence of other anticholinergic symptoms or signs, and neuroleptic malignant syndrome. The principal effects of Fargan overdose are central nervous system depression and anticholinergic effects, including delirium, agitation, and hallucinations. In an analysis of a series of cases of Fargan overdose in a prospective database of poisoning admissions to an Australian regional toxicology service, the main feature of Fargan toxicity was delirium, the probability of which was related to dose . Administration of activated charcoal reduced the probability of delirium.
The boxed warning now clearly reads that Fargan hydrochloride injections should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. It also advises caution should be exercised when administering the drug in the form of an injection to patients 2 years and older.
In 2006, an FDA alert advised all health care professionals that the warning extended to Fargan hydrochloride (including brand name Phenergan and generic versions of the drug) in any form, whether syrups, suppositories, tablets or injectables.
What Is Fargan (Phenergan)?
Fargan is the generic form of the brand-name drug Phenergan, used as an antihistamine, sedative, and anti-nausea drug.
Your doctor may also prescribe Fargan to relieve allergy symptoms like runny nose and watery, red eyes, or prevent and treat motion sickness.
Additionally, it can help with allergic skin conditions or reactions to blood or plasma products and may be used to treat the discomforts of a common cold like sneezing, coughing, and runny nose.
Physicians might combine Fargan with other drugs to help relieve a sudden allergic reaction known as anaphylaxis.
This medication may also be given to relax and sedate people before and after surgery, during labor, or to prevent and control the nausea and vomiting that may occur after surgery.
When combined with narcotic pain medication after surgery, it can improve the effectiveness of the pain medication.
The Food and Drug Administration (FDA) first approved Fargan hydrochloride in 1951.
It's marketed by Morton Grove Pharmaceuticals, Inc., and is available as a tablet, syrup, or a suppository to use rectally.
Missed Dose of Fargan DM
If you miss a dose of Fargan DM, take it as soon as you remember.
But if it's almost time for your next dose, skip the missed dose and continue on your regular medication schedule.
Don't take extra medicine to make up for a missed dose.
By Lynn Marks | Medically Reviewed by Robert Jasmer, MD
Latest Update: 2016-01-14 Copyright © 2014 Everyday Health Media, LLC
Phenergan (Wyeth), Fellozine (O’Neal, Jones & Feldman), Lemprometh (Lemmon), Provigan (Re >Fargan is not a scheduled drug.
Fargan is a phenothiazine derivative and a potent antihistamine with moderate antimuscarinic activity. Although more than 80% is absorbed, Fargan undergoes extensive first-pass hepatic glucuronidation and sulfoxidation, resulting in low absolute bioavailability of approximately 25%. 67 Peak plasma concentrations of Fargan (2.4–18.0 ng/mL) are observed between 1.5 and 3 hours after administration ( Fig. 34.11A ). Like other drugs that undergo extensive hepatic first-pass metabolism, plasma concentrations of its metabolite, Fargan sulfoxide (PMZSO), peak earlier and higher following oral administration compared with intravenous administration (see Fig. 34.11B ). 67 Overall, however, PMZSO plasma AUCs are not significantly different following oral or intravenous administration. Time to effect after intravenous and intramuscular injection is 5 and 20 minutes, respectively. 68 With a plasma half-life after intravenous and intramuscular injection of 9 to 16 hours and 6 to 13 hours, respectively, Fargan's duration of effect is typically 4 to 6 hours, up to 12 hours. 68
Fargan’s Risk of Tissue Injury
In 2009, the FDA required a second boxed warning for Fargan hydrochloride injection to warn patients of the risks of severe tissue injury with injectable administration, including gangrene and necrosis (death of a body tissue when there is not enough blood flow to the tissue).
Because of the risk for tissue injury with administering injectable Fargan both intravenously and subcutaneously (into the layer of skin directly below the dermis and epidermis), the FDA advised manufacturers to include in the boxed warning that the preferred route of administration for injectable Fargan is deep intramuscular injection (directly into a muscle).
Fargan should not be given by intra-arterial injection (within an artery) under any circumstances because it may cause severe arteriospasm (spasm in an artery) and result in gangrene. In fact, the Institute for Safe Medication Practices now recommends that injectable Fargan should be eliminated from hospital use.
Nausea and Vomiting
Antiemetics should not be used in vomiting of unknown etiology in children and adolescents (see WARNINGS-Use in Pediatric Patients).
The average effective dose of Fargan hydrochloride for the active therapy of nausea and vomiting in children or adults is 25 mg. When oral medication cannot be tolerated, the dose should be given parenterally (cf. Fargan Injection) or by rectal suppository. 12.5- to 25-mg doses may be repeated, as necessary, at 4-to 6-hour intervals.
For nausea and vomiting in children, the usual dose is 0.5 mg per pound of body weight, and the dose should be adjusted to the age and weight of the patient and the severity of the condition being treated. For prophylaxis of nausea and vomiting, as during surgery and the postoperative period, the average dose is 25 mg repeated at 4- to 6-hour intervals, as necessary.
Missed Dose of Fargan
If you miss a dose, take it as soon as you remember unless it's almost time for the next dose.
If that's the case, skip the missed dose and resume your regular dosing schedule.
Fargan can cause severe drowsiness. When you take certain anxiety drugs with Fargan, you may have drowsiness that is more extreme and lasts longer. Examples of these drugs include: