Antisedan

Sterile Injectable Solution - 5.0 mg/mL

Dexmedetomidine and Medetomidine Reversing Agent

For intramuscular use in dogs only

Federal law restricts this drug to use by or on the order of a licensed veterinarian.

ANTISEDAN (atipamezole hydrochloride) is a synthetic α₂-adrenergic antagonist.

The chemical name is 4-(2-ethyl-2,3-dihydro-1H-inden-2-yl)-1H-imidazole hydrochloride.

The molecular formula is C₁₄H₁₆N₂ • HCl and structural formula is:

Each mL of ANTISEDAN contains 5.0 mg atipamezole hydrochloride, 1.0 mg methylparaben (NF), 8.5 mg sodium chloride (USP), and water for injection (USP).

ANTISEDAN is indicated for the reversal of the sedative and analgesic effects of DEXDOMITOR (dexmedetomidine hydrochloride), and DOMITOR (medetomidine hydrochloride) in dogs.

ANTISEDAN is administered intramuscularly regardless of the route used for DEXDOMITOR or DOMITOR. The atipamezole dose for the reversal of IV DEXDOMITOR or DOMITOR is 3750 mcg/m². The atipamezole dose for the reversal of IM DEXDOMITOR or DOMITOR is 5000 mcg/m². The concentration of ANTISEDAN is formulated so that the volume of injection is the same (mL for mL) as the recommended dose of DEXDOMITOR or DOMITOR.

The dosage of ANTISEDAN is calculated based on body surface area. Use the following tables to determine the correct injection volume or the correct ANTISEDAN dosage on the basis of kilograms of body weight.

Note that the mcg/kg dosage decreases as body weight increases.

Since atipamezole is always used concomitantly with dexmedetomidine or medetomidine, it should not be used in dogs with the following conditions: cardiac disease, respiratory disorders, liver or kidney diseases, dogs in shock, severely debilitated dogs, or dogs stressed due to extreme heat, cold or fatigue.

Administration of atipamezole is contraindicated in dogs with a known hypersensitivity to the drug.

Not for human use. Keep out of reach of children.

Atipamezole hydrochloride can be absorbed and may cause irritation following direct exposure to skin, eyes, or mouth. In case of accidental eye exposure, flush with water for 15 minutes. In case of accidental skin exposure, wash with soap and water. Remove contaminated clothing.

If irritation or other adverse reaction occurs (for example, increased heart rate, tremor, muscle cramps), seek medical attention.

In case of accidental oral exposure or injection, seek medical attention. Caution should be used while handling and using filled syringes. Users with cardiovascular disease (for example, hypertension or ischemic heart disease) should take special precautions to avoid any exposure to this product.

The material safety data sheet (MSDS) contains more detailed occupational safety information.

To report adverse reactions in users or to obtain a copy of the MSDS for this product call 1-800-366-5288.

Occasional vomiting may occur. At times, a period of excitement or apprehensiveness may be seen in dogs treated with atipamezole. Other effects of atipamezole include hypersalivation, diarrhea, and tremors.

Atipamezole is a potent alpha₂-antagonist which selectively and competitively inhibits alpha₂-adrenergic receptors. The result of atipamezole administration in the dog is the rapid recovery from the sedative and analgesic effects produced by the alpha₂-adrenergic agonists dexmedetomidine or medetomidine. Atipamezole does not reverse the effects of other classes of sedatives, anesthetics, or analgesics.

Atipamezole is rapidly absorbed following intramuscular injection; maximum serum concentration is reached in approximately 10 minutes. Onset of arousal is usually apparent within 5 to 10 minutes of injection, depending on the depth and duration of dexmedetomidine- or medetomidine-induced sedation. Elimination half-life from serum is less than 3 hours. Atipamezole undergoes extensive hepatic biotransformation, with excretion of metabolites primarily in urine.

Dexmedetomidine or medetomidine activation of peripheral and central alpha₂-adrenergic receptors induces a pattern of pharmacological responses that include sedation, reduction of anxiety, analgesia, and bradycardia.

Blood pressure is initially increased due to peripheral vasoconstriction and thereafter drops to normal or slightly below normal levels. A transient, decrease in systolic blood pressure occurs immediately after administration of atipamezole to dexmedetomidine- or medetomidine-sedated dogs, followed by a transient increase in arterial pressure within 10 minutes compared to pre-atipamezole levels. This is the opposite of the response to alpha₂-agonist treatment, and is probably due to atipamezole-induced peripheral vasodilation.

Atipamezole administration rapidly abolishes dexmedetomidine- or medetomidine-induced bradycardia, usually within 3 minutes. The magnitude of the effect of atipamezole on heart rate is greater when dexmedetomidine is administered intravenously compared to intramuscularly. Dogs receiving medetomidine or IM dexmedetomidine may not return to pre-sedative heart rates after atipamezole administration and some dogs briefly show heart rate elevations above baseline. Respiratory rate increases following atipamezole injection.

One hundred and nine dogs received atipamezole in the field study (55 dogs received the reversal agent following dexmedetomidine; 54 following medetomidine). The mean age was 5.9 years and ranged between 17 weeks and 16 years. The mean weight was 45.5 lbs (20.7 kg), ranging from 4.8 lbs to 117 lbs (2.2 kg to 53.2 kg). Atipamezole was administered by the IM route of administration, within a range of 39-57 minutes after administration of either dexmedetomidine (IV and IM) or medetomidine (IV and IM).

Atipamezole reversed the effects of dexmedetomidine and medetomidine in all cases. In dexmedetomidine treated dogs, the onset of reversal was evident within 5 minutes after administration of atipamezole (57% could stand). Within 15 minutes, 96% of dexmedetomidine treated dogs were standing, 92% responded normally to sound, 86% had a normal muscle tone of jaw, and >90% had a normal pedal reflex response. Responses in dogs treated with medetomidine were similar or slightly later.

Following atipamezole, heart rate increased between 0 and 5 minutes following either alpha₂-agonist (IV dexmedetomidine dogs had heart rates from 60 to 85 bpm, and IV medetomidine dogs from 51 to 67 bpm; IM dexmedetomidine dogs had heart rates from 45 to 73 bpm, and IM medetomidine dogs from 52 to 79 bpm). Bradycardia resolved more slowly in the IM treatment groups. The body temperature remained at the same level during the 120 minutes of follow-up after atipamezole administration. Respiratory rates increased toward normal between 0 and 5 minutes after the administration of atipamezole in all treatment groups. Mucous membranes were described as normal after 5 minutes in 91% of dexmedetomidine dogs (IV or IM). By 120 minutes, 96% were normal (after IV dexmedetomidine) or 100% were normal (after IM dexmedetomidine). Many physiological responses were slightly slower to return toward normal when dogs were treated with medetomidine IV or IM.

No adverse events were reported in the atipamezole treated dogs.

Atipamezole was tolerated in healthy dogs receiving 10× the recommended dose and in dogs receiving repeated doses at 1, 3, and 5× the recommended dose, in the absence of an alpha₂-agonist. Signs were dose-related and included excitement, panting, trembling, vomiting, soft or liquid feces and scleral injection. At 10× the recommended dose, increases in creatine kinase, AST, and ALT were noted. Creatine kinase also increased in 3 (of 6) dogs in the 3× treatment group. Localized skeletal muscle injury was seen at the injection site but no associated clinical signs or complications were observed. Dogs receiving the recommended atipamezole dose in the absence of medetomidine or dexmedetomidine exhibited no adverse clinical signs. In additional safety studies, adverse events were absent up to the 3× dose of atipamezole when its administration followed medetomidine or dexmedetomidine sedation.

In a separate safety study using a crossover design, 5 dogs received atipamezole after dexmedetomidine (IV and IM). Dexmedetomidine's effects on blood pressure, heart rate, respiratory rate, and cardiac conduction times were reversed by atipamezole. However, heart rate and cardiac conduction times did not return to predexmedetomidine values. Heart rate increases after atipamezole were closer to baseline values in dogs treated with dexmedetomidine IV (compared to IM).

Store protected from light at controlled room temperature 15°–30°C (59°–86°F).

ANTISEDAN is supplied in 10-mL, multidose vials containing 5.0 mg of atipamezole hydrochloride per mL.

Antisedan^®, Dexdomitor^®, and Domitor^® are trademarks of Orion Corporation.

Developed and manufactured by:
ORION
PHARMA
Orion Corporation
Espoo, Finland

Distributed by:
Pfizer Animal Health
Div. of Pfizer Inc
NY, NY 10017

107237US-5

Made in Finland

Jaakkoo-Taara Oy

NADA #141-033, Approved by FDA

Net Contents: 10 mL

ANTISEDAN^®
(atipamezole hydrochloride)
Sterile Injectable Solution - 5.0 mg/mL

Dexmedetomidine and Medetomidine Reversing Agent
For intramuscular use in dogs only

Caution: Federal law restricts this drug to use by
or on the order of a licensed veterinarian.

NADA #141-033, Approved by FDA

ORION
PHARMA

Pfizer