Each vial contains Butorphanol 1 mg.
Pharmacology: Pharmacokinetics: Peak plasma concentrations occur 0.5 to 1 hour after intramuscular dose. Butorphanol has a plasma elimination half-life of about 3 hours. About 80% is bound to plasma proteins. Butorphanol is extensively metabolized in the liver through hydroxylation, N-dealkylation, and conjugation, only 5% being excreted unchanged. Excretion is mainly in the urine; about 15% of a parenteral dose is excreted in the bile. It crosses the placenta and is distributed into breast milk.
Butorphanol tartrate, a phenanthrene derivative, is an opioid analgesic with opioid agonist and antagonist properties; it is pharmacologically similar to pentazocine. Butorphanol is used for the relief of moderate to severe pain and as an adjunct to anaesthesia. Onset of analgesia occurs within 10 to 15 minutes of intramuscular injection and may last for 3 to 4 hours.
For the relief of moderate to severe pain, butorphanol tartrate is given in doses of 1 to 4 mg by intramuscular injection or in doses of 0.5 to 2 mg by intravenous injection every 3 to 4 hours. This sequence may be repeated after 3 to 4 hours as needed. In anaesthesia, 2 mg may be given intramuscularly for premedication 60 to 90 minutes before surgery. For use in balanced anaesthesia a usual dose is 2 mg given intravenously shortly before induction followed by 0.5 to 1 mg intravenously in increments during anaesthesia. Dosage adjustment may be needed in the elderly. When given by injection the initial dose of butorphanol for pain should be half the usual initial adult dose. Subsequent doses should be determined by the patient's response; a dosage interval of at least 6 hours has been recommended. Administration in hepatic or renal impairment. The dosage of butorphanol may need to be adjusted in patients with hepatic or renal impairment. When given by injection the initial dose for pain should be half the usual initial adult dose. Subsequent doses should be determined by the patient's response; a dosage interval of at least 6 hours has been recommended. Or as prescribed by the physician.
Opioid analgesics are generally contraindicated in acute respiratory depression and obstructive airways disease, although opioids such as morphine are used in some forms of dyspnoea. They are also contraindicated or should be used with great caution in acute alcoholism, convulsive disorders, head injuries, and conditions in which intracranial pressure is raised. They should not be given to comatose patients.
Opioid analgesics should be given with caution or in reduced doses to patients with hypothyroidism, adrenocortical insufficiency, asthma or decreased respiratory reserve, renal or hepatic impairment, prostatic hyperplasia, hypotension, shock, inflammatory or obstructive bowel disorders, or myasthenia gravis. Dosage should be reduced in elderly or debilitated patients.
Opioid analgesics should be given with great care to infants, especially neonates. Their use during labour may cause respiratory depression in the neonate. Babies born to opioid-dependent mothers may suffer withdrawal symptoms. Therapy with opioid analgesics should be stopped gradually in patients who may have developed physical dependence, to avoid precipitating withdrawal symptoms. Opioid analgesics with some antagonist activity, such as buprenorphine, butorphanol, nalbuphine, or pentazocine, may precipitate withdrawal symptoms in physically dependent patients who have recently used pure agonists such as morphine.
Drowsiness may affect the ability to perform skilled tasks; those so affected should not drive or operate machinery. Opioids are usually contraindicated in asthma. However it has been suggested that they are safe in controlled asthma, but should be avoided during acute exacerbations.
In normal doses, the most common adverse effects of opioid analgesics are nausea, vomiting, constipation, drowsiness, and confusion; tolerance to these (except constipation) generally develops with long-term use. Micturition may be difficult and there may be ureteric or biliary spasm; the latter may be associated with alterations in liver enzyme values. There is also an antidiuretic effect. Dry mouth, dizziness, sweating, facial, flushing, headache, vertigo, bradycardia, tachycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, changes of mood, decreased libido or potency, hallucinations, and miosis also occur. These effects tend to occur more commonly in ambulant patients than in those at rest in bed and in those without severe pain. Raised intracranial pressure occurs in some patients. Muscle rigidity has been reported following high doses. The euphoric activity of opioids has led to their abuse. Larger doses of opioids produce respiratory depression and hypotension, with circulatory failure and deepening coma. Convulsions may occur, especially in infants and children. Rhabdomyolysis progressing to renal failure has been reported in overdosage. Death may occur from respiratory failure. Toxic doses of specific opioids vary considerably with the individual and regular users may tolerate large doses. The triad of coma, pinpoint pupils, and respiratory depression is considered indicative of opioid overdosage; dilatation of the pupils occurs as hypoxia develops. Pulmonary edema after overdosage is a common cause of fatalities among opioid addicts. Morphine and some other opioids have a dose-related histamine-releasing effect which may be responsible in part of reactions such as urticaria and pruritus as well as hypotension and flushing. Contact dermatitis has been reported and pain and irritation may occur on injection. Anaphylactic reactions after intravenous injection have been reported rarely. Headache and feelings of floating may also occur. Hallucinations and other psychotomimetic effects are rare and have been reported less frequently than with pentazocine.
Butorphanol has opioid agonist and antagonist activity; naloxone is the recommended antagonist for the treatment of overdosage.
Effects on the respiratory system.
Butorphanol 2 mg produces a similar degree of respiratory depression to morphine 10 mg, but a ceiling effect is apparent with higher doses of butorphanol. It has been reported to be a less potent respiratory depressant than fentanyl, but more potent than nalbuphine.
As serious and sometimes fatal reactions have followed use of pethidine in patients receiving MAOls (including moclobemide), pethidine and related drugs are contraindicated in patients taking MAOIs or within 14 days of stopping such treatment; other opioid analgesics should be avoided or given with extreme caution. Life-threatening reactions have also been reported when selegiline, a selective inhibitor of monoamine oxidase type B, has been given with pethidine. The depressant effects of opioid analgesics are enhanced by other CNS depressants such as alcohol, anaesthetics, anxiolytics, hypnotics, tricyclic antidepressants, and antipsychotics. Cyclizine may counteract the haemodynamic benefits of opioids. Cimetidine inhibits the metabolism of some opioids, especially pethidine. The actions of opioids may in turn affect the activities of other drugs. For instance, their gastrointestinal effects may delay absorption as with mexiletine or may be counteractive as with cisapride, metoclopramide, or domperidone. Opioid premedicants such as papaveretum have been reported to reduce serum concentrations of ciprofloxacin.
Alcohol. Rapid release or dose-dumping of hydromorphone from a modified-release preparation has been associated with the ingestion of alcohol.
Antiviral. Interactions between opioid analgesics and ritonavir, other HIV-protease inhibitors, or reverse transcriptase inhibitors are complex, and the results of the limited number of studies and reports in vivo have not always borne out predictions about the nature of potential interactions.
Histamine H2-antagonists. Histamine H2-antagonists may enhance the effects of some opioid analgesics. Cimetidine was reported to alter the clearance and volume of distribution of pethidine whereas ranitidine did not. Morphine has been considered less likely to interact with cimetidine than pethidine because of differences in metabolism. However, although cimetidine did not affect the disposition of morphine in healthy subjects in a study there have been isolated reports of possible interactions between morphine and H2-antagonists; apnea, confusion, and muscle twitching have been associated with cimetidine plus morphine and confusion associated with ranitidine with morphine. There has also been a report of a patient receiving regular analgesia with oral methadone and subcutaneous morphine who became unresponsive 6 days after starting cimetidine for prophylaxis of peptic ulcer; treatment with naloxone was required.
Store at temperatures not exceeding 30°C.
N02AF01 - butorphanol ; Belongs to the class of morphinan derivative opioids. Used to relieve pain.
Soln for inj (vial) 1 mg/mL x 1 mL x 1's, 10's.