SCANDONEST 2 % SPECIAL

Indications

• Local anesthesia for minor surgical procedures
• Anaesthesia before venepuncture
• Anaesthesia for skin lesions
• Regional anesthesia techniques (e.g., for cervical curettage or debridement of leg ulcers)

Dosage

Children: Neonate: Apply up to 1 g for a maximum of 1 hour before procedure, under occlusive dressing. For children 1-2 months, the same dosage applies. Consult BNF for Children for further dosing information.

Adults: Apply up to 10 g under occlusive dressing for 30–60 minutes before the procedure. Specific dosage may vary based on the procedure and patient condition; consult BNF for detailed guidelines.

Mechanism of action

Mepivacaine exerts its effects by binding to voltage-gated sodium channels on the neuronal cell membrane, inhibiting sodium influx, which is essential for the generation and conduction of action potentials in nerve fibers. This leads to a reversible loss of sensation in the targeted area.

Pharmacodynamics

Mepivacaine provides rapid onset of anesthesia, with effects typically lasting between 1 to 3 hours depending on the mode of administration and concentration used. It is favored for its lower potential for vasodilation compared to other local anesthetics, thus providing a more prolonged effect in certain settings.

Pharmacokinetics

Mepivacaine is rapidly absorbed into the bloodstream when administered parenterally. It is metabolized primarily in the liver and excreted in the urine, with a half-life of approximately 1.5 to 2.5 hours in healthy adults. The drug's pharmacokinetics can be altered in patients with hepatic impairment, necessitating caution in such populations.

Contra-indications

• Avoid injection into infected tissues
• Avoid injection into inflamed tissues
• Severe atrio-ventricular conduction disorders not controlled by a pacemaker
• Hypersensitivity to mepivacaine or other amide local anesthetics

Adverse effects

• Arrhythmia
• Dizziness
• Hypertension
• Hypotension
• Nausea
• Paraesthesia
• Vomiting
• Neurotoxicity
• Sexual dysfunction (in adults)
• Methaemoglobinaemia
• Fever (in adults)
• Headache (in adults)
• Skin reactions

Interactions

• Antiarrhythmics
• Other local anesthetics

Precautions

• Consider dose reduction in elderly and debilitated patients
• Caution in patients with cardiovascular disease, epilepsy, hypovolaemia, impaired cardiac conduction, impaired respiratory function, and myasthenia gravis
• Increased risk of toxic plasma concentrations in patients with hepatic impairment

Pregnancy

Use with caution in early pregnancy.

Breast-feeding

Use with caution.

Storage

Store below 25°C, protect from light.

Formulations

• Mepivacaine hydrochloride cream 5% (Denela, Emla, Nulbia), containing 25 mg of lidocaine and 25 mg of prilocaine per gram

Indications

• Anaphylaxis
• Cardiac arrest

Mechanism of action

Epinephrine acts on alpha and beta-adrenergic receptors, functioning as the strongest alpha receptor activator. It minimizes vasodilation and vascular permeability during anaphylaxis, thus preventing hypotension and loss of intravascular fluid volume. It relaxes bronchial smooth muscle and acts as a histamine antagonist, which is beneficial in managing allergic reactions. The drug's effects include increasing blood sugar and glycogenolysis in the liver, while its beta-adrenergic actions lead to bronchial smooth muscle relaxation, relieving bronchospasm, wheezing, and dyspnea. It also increases blood pressure through positive inotropic and chronotropic actions, alongside vasoconstriction in various vascular beds.

Pharmacodynamics

Epinephrine is classified as a sympathomimetic agent, mimicking sympathetic nervous system actions on effector cells. It leads to increased heart rate and contractility via beta-1 receptors and induces bronchodilation through beta-2 receptor activation. Its therapeutic use extends to alleviating symptoms of croup, pruritus, urticaria, and angioedema. Additionally, it relaxes smooth muscle in the gastrointestinal and genitourinary tracts, providing symptom relief during anaphylactic responses.

Pharmacokinetics

Epinephrine is rapidly distributed throughout the body and has a short half-life. It is metabolized primarily in the liver and other tissues by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). The onset of action is typically within minutes when administered intramuscularly or intravenously, and it is excreted mainly in the urine as metabolites. The pharmacokinetics may vary based on the route of administration and clinical condition of the patient.

Contra-indications

• Hypersensitivity to epinephrine or any of its components
• Narrow-angle glaucoma
• Organic brain damage
• Cardiac tachyarrhythmias
• Coronary artery disease
• Cerebrovascular disease

Adverse effects

• Tachycardia
• Palpitations
• Hypertension
• Anxiety
• Tremors
• Headache
• Dizziness
• Nausea
• Vomiting
• Pallor
• Sweating
• Respiratory difficulty

Interactions

• Monoamine oxidase inhibitors
• Tricyclic antidepressants
• Beta-blockers
• Digoxin
• Diuretics
• Other sympathomimetic agents

Precautions

• Use with caution in patients with diabetes mellitus due to its potential to raise blood sugar levels
• Monitor cardiovascular status in patients with underlying heart disease
• Caution in patients with hyperthyroidism or history of seizure disorders
• Avoid extravasation during intravenous administration to prevent tissue necrosis

Pregnancy

Epinephrine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Epinephrine is excreted in breast milk, and caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Injection solution (1:1000) for intramuscular or subcutaneous use
• Auto-injector device
• Nebulized solution for inhalation
• Injection solution (1:10000) for intravenous use

Indications

• Local infiltration anesthesia
• Regional anesthesia
• Dental procedures
• Minor surgical procedures

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Local anesthetics block the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse, and by reducing the rate of rise of the action potential. The order of loss of nerve function typically follows pain, temperature, touch, proprioception, and skeletal muscle tone.

Pharmacodynamics

Mepivicaine is an amide local anesthetic characterized by a reasonably rapid onset and medium duration of action. Systemic absorption can lead to minimal effects on the cardiovascular and central nervous systems, with limited changes in cardiac conduction, excitability, refractoriness, contractility, and peripheral vascular resistance at therapeutic doses.

Pharmacokinetics

Mepivacaine is absorbed systemically when used in local anesthesia, leading to effects on the cardiovascular and central nervous systems. Its pharmacokinetics involve metabolism primarily in the liver, with renal excretion of metabolites. The specific half-life and distribution can vary based on the route of administration and patient factors.

Contra-indications

• Hypersensitivity to mepivacaine or other amide local anesthetics
• Severe heart block
• Hypovolemia
• Infection at the injection site

Adverse effects

• Dizziness
• Tinnitus
• Nausea
• Vomiting
• Headache
• Allergic reactions
• Cardiovascular effects such as hypotension or arrhythmias

Interactions

• Other local anesthetics can increase the risk of toxicity
• Certain antiarrhythmics may have additive effects on cardiac conduction
• Monoamine oxidase inhibitors (MAOIs) may enhance the effects of local anesthetics

Precautions

• Use with caution in patients with hepatic impairment
• Caution in patients with cardiovascular disease
• Monitor for signs of systemic toxicity during administration
• Use with caution in pregnant patients

Pregnancy

Mepivacaine should only be used during pregnancy if the benefits outweigh the risks. Limited data is available on its safety in pregnant women.

Breast-feeding

Mepivacaine is excreted in breast milk. Caution is advised if the mother is breastfeeding.

Storage

Store at room temperature, away from light and moisture. Do not freeze.

Formulations

• Injection solution (e.g., 1%, 2% concentrations)

Mechanism of action

Epinephrine acts on alpha and beta-adrenergic receptors. Epinephrine acts on alpha and beta receptors and is the strongest alpha receptor activator. Through its action on alpha-adrenergic receptors, epinephrine minimizes the vasodilation and increased the vascular permeability that occurs during anaphylaxis, which can cause the loss of intravascular fluid volume as well as hypotension. Epinephrine relaxes the smooth muscle of the bronchi and iris and is a histamine antagonist, rendering it useful in treating the manifestations of allergic reactions and associated conditions. This drug also produces an increase in blood sugar and increases glycogenolysis in the liver. Through its action on beta-adrenergic receptors, epinephrine leads to bronchial smooth muscle relaxation that helps to relieve bronchospasm, wheezing, and dyspnea that may occur during anaphylaxis. The mechanism of rise in blood pressure ... is threefold: a direct myocardial stimulation that increases the strength of ventricular contraction (positive inotropic action), an increased heart rate (positive chronotropic action), vasoconstriction in many vascular beds, especially in precapillary resistance vessels of skin, mucosa, and kidney, along with marked constriction of veins. ... Epinephrine affects respiration primarily by relaxing bronchial muscle. It has a powerful bronchodilator action, most evident when bronchial muscle is contracted because of disease, as in bronchial asthma, or in response to drugs or various autacoids. In such situations, epinephrine has a striking therapeutic effect as a physiological antagonist to substances that cause bronchoconstriction. The beneficial effects of epinephrine in asthma also may arise from inhibition of antigen-induced release of inflammatory mediators from mast cells, and to a lesser extent from diminution of bronchial secretions and congestion within the mucosa. Inhibition of mast cell secretion is mediated by beta2 receptors, while the effects on the mucosa are mediated by alpha receptors The electrophysiologic effects of circulating epinephrine in humans were examined in four study groups of 10 subjects each. In 10 subjects without structural heart disease (Group 1) and in 10 patients with coronary disease or dilated cardiomyopathy (Group 2) epinephrine infusion at 25 and 50 ng/kg body weight per min for 14 min resulted in an elevation of the plasma epinephrine concentration in the physiologic range. In both groups it produced a dose-dependent decrease in the effective refractory period of the atrium, atrioventricular node and ventricle and improvement in atrioventricular node conduction. Epinephrine facilitated the induction of sustained ventricular tachycardia in 3 of the 20 subjects. In Group 3, a beta-adrenergic blocking dose of propranolol was added to the infusion of 50 ng/kg per min of epinephrine. Propranolol not only reversed the effects of epinephrine, but also lengthened these variables compared with baseline values. In group 4, propranolol was administered first, followed by 50 ng/kg per min of epinephrine. Propranolol alone slowed atrioventricular node conduction and mildly prolonged the refractory periods. In the presence of beta-blockade, epinephrine had no effect on atrioventricular node properties but resulted in a lengthening of the atrial and ventricular effective refractory periods. In conclusion, epinephrine in physioloic doses shortens the effective refractory period of the atrium, atrioventricular node and ventricle, improves atrioventricular node conduction and may facilitate the induction of sustained ventricular tachycardia. The overall electrophysiologic effects of epinephrine result from stimulation of beta-receptors. Stimulation of alpha-receptors by epinephrine has no effect on the atrioventricular node but prolongs the effective refractory period of the atrium and ventricle, partially offsetting the shortening of refractory periods mediated by beta-receptor stimulation. Epinephrine

Pharmacodynamics

Epinephrine is a sympathomimetic drug. It causes an adrenergic receptive mechanism on effector cells and mimics all actions of the sympathetic nervous system except those on the facial arteries and sweat glands. Important effects of epinephrine include increased heart rate, myocardial contractility, and renin release via beta-1 receptors. Beta-2 effects produce bronchodilation which may be useful as an adjunct treatment of asthma exacerbations as well as vasodilation, tocolysis, and increased aqueous humor production. In croup, nebulized epinephrine is associated with both clinically and statistically significant transient reduction of croup symptoms 30 minutes post-treatment. Epinephrine also alleviates pruritus, urticaria, and angioedema and may be helpful in relieving gastrointestinal and genitourinary symptoms associated with anaphylaxis because of its relaxing effects on the smooth muscle of the stomach, intestine, uterus, and urinary bladder.

Mechanism of action

Local anesthetics block the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse, and by reducing the rate of rise of the action potential. In general, the progression of anesthesia is related to the diameter, myelination, and conduction velocity of affected nerve fibers. Clinically, the order of loss of nerve function is as follows: pain, temperature, touch, proprioception, and skeletal muscle tone.

Pharmacodynamics

Mepivicaine is an amide local anesthetic. Mepivicaine as a reasonably rapid onset and medium duration and is known by the proprietary names as Carbocaine and Polocaine. Mepivicaine is used in local infiltration and regional anesthesia. Systemic absorption of local anesthetics produces effects on the cardiovascular and central nervous systems. At blood concentrations achieved with normal therapeutic doses, changes in cardiac conduction, excitability, refractoriness, contractility, and peripheral vascular resistance are minimal.