Dermazyl

Uses

Dimethicone is an ingredient used to treat dry and irritated eyes.

Dimethicone is a colorless liquid with both cosmetic and therapeutic uses. It is used in topical creams and ointments to help distribute the active ingredients. Dimethicone is used as an anti-foaming agent, a hair and skin conditioner, and in the treatment of head lice and, as an anti-bloating/anti-flatulence agent , .

Lidocaine is a topical anesthetic used for the following purposes-

• To help prevent pain associated with minor surgical procedures in the ear, nose and throat
• To help prevent pain and or discomfort during dental procedures (e.g., prior to an injection)
• During general anesthesia to prevent coughing
• To help prevent pain during the final stages of childbirth, before the cutting or stitching of the perineum (skin between the vagina and anus)

Dermazyl is also used to associated treatment for these conditions: Acute Diarrhoea, Aerophagy, Dry Skin, Duodenal Ulcer, Dyspepsia, Flatulence, Gastric Ulcer, Gastritis, Gastro-esophageal Reflux Disease (GERD), Hiatus Hernia, Pancreatic Insufficiency, Post Operative Gas, Pre-operative Gas, Stress Ulcers, Bowel preparation therapy, Carbohydrate Digestion, Digestive Aid, Fat Digestion, Protein DigestionAcute Otitis Media, Anal Fissures, Anorectal discomfort, Arrhythmia, Back Pain Lower Back, Bacterial Vaginosis (BV), Burns, Cervical Syndrome, Earache, Hemorrhoids, Infection, Inflammatory Reaction caused by ear infection-not otherwise specified, Insect Bites, Joint Pain, Mixed Vaginal Infections, Multiple Myeloma (MM), Myringitis, Neuritis, Osteolysis caused by Bone Tumors, Osteoporosis, Otitis Externa, Pain caused by ear infection-not otherwise specified, Pain, Inflammatory, Post-Herpetic Neuralgia (PHN), Postherpetic Neuralgia, Primary Hyperparathyroidism, Rheumatic Diseases, Rheumatic Joint Disease, Sciatica, Skin Irritation, Soft Tissue Inflammation, Sore Throat, Sunburn, Susceptible infections, Trichomonas Vaginitis, Ulcers, Leg, Urethral Strictures, Vulvovaginal Candidiasis, Abrasions, Anal discomfort, Arrhythmia of ventricular origin, Cutaneous lesions, Gum pain, Minor burns, Superficial Wounds, Susceptible Bacterial Infections, Ulceration of the mouth, Viral infections of the external ear canal, Post Myocardial Infarction Treatment, Regional Anesthesia, Local anesthesia therapy

How Dermazyl works

When applied topically, dimethicone forms a layer to delay the evaporation of water . In the treatment of head lice dimethicone 100, the respiratory systems of head lice are targeted. NYDA works by suffocating the lice, nymphs and the embryos. The physical properties of this drug, including the viscosity and spreading property of the solution allow it to easily flow into the respiratory system of all developmental stages of the insect, causing suffocation and death of the organisms. It diffuses through the stigmata (spiracles) of the lice, into the tracheae of the head lice as well as through the aeropyles of the egg operculum. The solution then displaces oxygen. The low viscosity, volatile dimethicone enables the NYDA head lice solution to penetrate into the breathing system. Its evaporation causes the thickening of the NYDA solution. The remaining high viscosity dimethicone ultimately encloses the respiratory system and thus leading to suffocation of all stages of head lice (adult lice, larvae and eggs). This mode of action prevents the development of lice resistance by preventing the formation of new progency .

Studies performed using house crickets and lice suggest a close correlation between the death of the lice and the influx of the solution into the insect head tracheae. These data strongly suggest that the total filling of the head tracheae immediately blocks the oxygen supply to the insect central nervous system. Death, following numerous stages of disability after the entrance of dimethicones into the abdominal tracheal system, demonstrates the sequence of oxygen deprivation. NYDA was applied directly to the head and mouth of the organism, and was found to have no effect when applied solely to the outside of the head/mouth .

Lidocaine is a local anesthetic of the amide type . It is used to provide local anesthesia by nerve blockade at various sites in the body . It does so by stabilizing the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses, thereby effecting local anesthetic action . In particular, the lidocaine agent acts on sodium ion channels located on the internal surface of nerve cell membranes . At these channels, neutral uncharged lidocaine molecules diffuse through neural sheaths into the axoplasm where they are subsequently ionized by joining with hydrogen ions . The resultant lidocaine cations are then capable of reversibly binding the sodium channels from the inside, keeping them locked in an open state that prevents nerve depolarization . As a result, with sufficient blockage, the membrane of the postsynaptic neuron will ultimately not depolarize and will thus fail to transmit an action potential . This facilitates an anesthetic effect by not merely preventing pain signals from propagating to the brain but by aborting their generation in the first place .

In addition to blocking conduction in nerve axons in the peripheral nervous system, lidocaine has important effects on the central nervous system and cardiovascular system . After absorption, lidocaine may cause stimulation of the CNS followed by depression and in the cardiovascular system, it acts primarily on the myocardium where it may produce decreases in electrical excitability, conduction rate, and force of contraction .

Dosage

Dermazyl dosage

Intramuscular:Emergency treatment of ventricular arrhythmias: 300 mg injected into the deltoid muscle, repeat after 60-90 min if necessary.

Intraspinal:Spinal anaesthesia: As hyperbaric soln of 1.5% or 5% lidocaine in 7.5% glucose soln. Normal vaginal delivery: Up to 50 mg (as 5% soln) or 9-15 mg (as 1.5% soln). Caesarian operation: Up to 75 mg (as 5% soln). Other surgical procedures: 75-100 mg.Intravenous:Pulseless ventricular fibrillation or ventricular tachycardia : 1-1.5 mg/kg repeated as necessary. Max: 3 mg/kg. For ventricular arrhythmias in more stable patients: Usual loading dose: 50-100 mg as an IV inj at 25-50 mg/min, may repeat once or twice up to a max of 200-300 mg in 1 hr, followed by 1-4 mg/min via continuous IV infusion. May need to reduce dose if the infusion is longer than 24 hr.

Intravenous:Intravenous regional anaesthesia: As 0.5% soln w/o epinephrine: 50-300 mg. Max: 4 mg/kg.

Parenteral:Percutaneous infiltration anaesthesia: As 0.5% or 1% soln: 5-300 mg.Sympathetic nerve block: As 1% soln: 50 mg for cervical block or 50-100 mg for lumbar block.Peripheral nerve block:

• As 1.5% soln: For brachial plexus block: 225-300 mg.
• As 2% soln: For dental nerve block: 20-100 mg.
• As 1% soln: For intercostal nerve block: 30 mg;
• For paracervical block: 100 mg on each side, repeated not more frequently than every 90 min;
• For paravertebral block: 30-50 mg;
• For pudendal block: 100 mg on each side.
• As 4% soln: For retrobulbar block: 120-200 mg.

Spray:

• The maximum dose is 200 mg (Approximately 20 spray).
• In dentistry, the normal dose is 1-5 sprays. Two sprays per quarter of the mouth is recommended, with a maximum of 3 sprays per quarter of the mouth over 30 minutes.
• In sinus procedures 3 sprays are used.
• In procedures of the throat and windpipe, up to 20 sprays may be necessary.
• Up to 20 sprays may be necessary in childbirth (cesarian procedure).
• Lower doses are used for children aged 3-12 years. Lidocaine 10% Spray is not recommended for children under 3 years.

Topical: Anaesthesia before e.g. venepuncture (not for infants), apply a thick layer under an occlusive dressing 1-5 hours before procedure; split skin grafting, apply a thick layer under an occlusive dressing 2-5 hours before procedure; genital warts (not for children), apply up to 10 gm 5-10 minutes before removal.

Side Effects

Arrhythmia, bradycardia, arterial spasms, CV collapse, oedema, flushing, hert block, hypotension, sinus node suppression, agitation, anxiety, coma, confusion, drowsiness, hallucinations, euphoria, headache, hyperaesthesia, hypoaesthesia, lightheadedness, lethargy, nervousness, psychosis, seizure, slurred speech, unconsciousness, somnolence, nausea, vomiting, metallic taste, tinnitus, disorientation, dizziness, paraesthesia, resp depression and convulsions. Patch: Bruising, depigmentation, petechiae, irritation. Ophth: Conjunctival hyperaemia, corneal epithelial changes, diplopia,visual changes.

Toxicity

The minimum lethal oral dose of dimethicone 200 (50 cs), dimethicone 550 (75 cs), dimethicone in rats .

A 76-week dietary toxicity study of a silicone antifoam compound (94% polydimethylsiloxane silicone oil and 6% silicone dioxide) was performed in mice. Three groups were given diet containing 0, 0.25%, or 2.5% of the test article. The dose levels in the treatment groups were estimated to be 580 and 5800 mg/kg/day. Mortality was increased in the 5800 mg/kg/day females. No target organs of toxicity were observed. The no-effect dose was 580 mg/kg/day. This study is of limited usefulness for assessing the toxicity of dimethicones, due to the small number of organs/tissues that were examined .

In one clinical study, 145 subjects were treated with either NYDA (dimethicone )or with a permethrin-based lice product. The number of subjects experiencing any adverse events was similar in both groups. In the NYDA group, 29 adverse events were reported in 25 subjects. All except two adverse events were categorized as being unrelated to the lice treatment (e.g., superficial wound after a fall, otitis externa following swimming in a pool). Two patients in the NYDA group experienced ocular irritation after treatment when the product entered the eyes. The irritation resolved spontaneously in both cases after rinsing the eyes with clean water .

Symptoms of overdose and/or acute systemic toxicity involves central nervous system toxicity that presents with symptoms of increasing severity . Patients may present initially with circumoral paraesthesia, numbness of the tongue, light-headedness, hyperacusis, and tinnitus . Visual disturbance and muscular tremors or muscle twitching are more serious and precede the onset of generalized convulsions . These signs must not be mistaken for neurotic behavior . Unconsciousness and grand mal convulsions may follow, which may last from a few seconds to several minutes . Hypoxia and hypercapnia occur rapidly following convulsions due to increased muscular activity, together with the interference with normal respiration and loss of the airway . In severe cases, apnoea may occur. Acidosis increases the toxic effects of local anesthetics . Effects on the cardiovascular system may be seen in severe cases . Hypotension, bradycardia, arrhythmia and cardiac arrest may occur as a result of high systemic concentrations, with potentially fatal outcome .

Pregnancy Category B has been established for the use of lidocaine in pregnancy, although there are no formal, adequate, and well-controlled studies in pregnant women . General consideration should be given to this fact before administering lidocaine to women of childbearing potential, especially during early pregnancy when maximum organogenesis takes place . Ultimately, although animal studies have revealed no evidence of harm to the fetus, lidocaine should not be administered during early pregnancy unless the benefits are considered to outweigh the risks . Lidocaine readily crosses the placental barrier after epidural or intravenous administration to the mother . The ratio of umbilical to maternal venous concentration is 0.5 to 0.6 . The fetus appears to be capable of metabolizing lidocaine at term . The elimination half-life in the newborn of the drug received in utero is about three hours, compared with 100 minutes in the adult . Elevated lidocaine levels may persist in the newborn for at least 48 hours after delivery . Fetal bradycardia or tachycardia, neonatal bradycardia, hypotonia or respiratory depression may occur .

Local anesthetics rapidly cross the placenta and when used for epidural, paracervical, pudendal or caudal block anesthesia, can cause varying degrees of maternal, fetal and neonatal toxicity . The potential for toxicity depends upon the procedure performed, the type and amount of drug used, and the technique of drug administration . Adverse reactions in the parturient, fetus and neonate involve alterations of the central nervous system, peripheral vascular tone, and cardiac function .

Maternal hypotension has resulted from regional anesthesia . Local anesthetics produce vasodilation by blocking sympathetic nerves . Elevating the patient’s legs and positioning her on her left side will help prevent decreases in blood pressure . The fetal heart rate also should be monitored continuously, and electronic fetal monitoring is highly advisable .

Epidural, spinal, paracervical, or pudendal anesthesia may alter the forces of parturition through changes in uterine contractility or maternal expulsive efforts . In one study, paracervical block anesthesia was associated with a decrease in the mean duration of first stage labor and facilitation of cervical dilation . However, spinal and epidural anesthesia have also been reported to prolong the second stage of labor by removing the parturient’s reflex urge to bear down or by interfering with motor function . The use of obstetrical anesthesia may increase the need for forceps assistance .

The use of some local anesthetic drug products during labor and delivery may be followed by diminished muscle strength and tone for the first day or two of life . The long-term significance of these observations is unknown . Fetal bradycardia may occur in 20 to 30 percent of patients receiving paracervical nerve block anesthesia with the amide-type local anesthetics and may be associated with fetal acidosis . Fetal heart rate should always be monitored during paracervical anesthesia . The physician should weigh the possible advantages against risks when considering a paracervical block in prematurity, toxemia of pregnancy, and fetal distress . Careful adherence to the recommended dosage is of the utmost importance in obstetrical paracervical block . Failure to achieve adequate analgesia with recommended doses should arouse suspicion of intravascular or fetal intracranial injection . Cases compatible with unintended fetal intracranial injection of local anesthetic solution have been reported following intended paracervical or pudendal block or both. Babies so affected present with unexplained neonatal depression at birth, which correlates with high local anesthetic serum levels, and often manifest seizures within six hours . Prompt use of supportive measures combined with forced urinary excretion of the local anesthetic has been used successfully to manage this complication .

It is not known whether this drug is excreted in human milk . Because many drugs are excreted in human milk, caution should be exercised when lidocaine is administered to a nursing woman .

Dosages in children should be reduced, commensurate with age, body weight and physical condition .

The oral LD 50 of lidocaine HCl in non-fasted female rats is 459 (346-773) mg/kg (as the salt) and 214 (159-324) mg/kg (as the salt) in fasted female rats .

Precaution

Patient with pseudocholinesterase deficiency, resp depression. Hepatic and renal impairment. Elderly or debilitated patients. Pregnancy and lactation.

Interaction

May increase serum levels with cimetidine and propranolol. Increased risk of cardiac depression with β-blockers and other antiarrhythmics. Additive cardiac effects with IV phenytoin. Hypokalaemia caused by acetazolamide, loop diuretics and thiazides may antagonise effect of lidocaine. Dose requirements may be increased with long-term use of phenytoin and other enzyme-inducers.

Volume of Distribution

Following injection of [14C]dimethicone fluid in the hind limb of rats, the radioactivity was distributed primarily in the gastrointestinal tract, and no evidence of metabolism was observed. When [14C]dimethicone was administered through i.p. injection in rats, the following distribution of radioactivity was observed at 25 days after dosing: 51% in adipose tissue, 27% in gastrointestinal tissues, and 15% in liver .

The volume of distribution determined for lidocaine is 0.7 to 1.5 L/kg .

In particular, lidocaine is distributed throughout the total body water . Its rate of disappearance from the blood can be described by a two or possibly even three-compartment model . There is a rapid disappearance (alpha phase) which is believed to be related to uptake by rapidly equilibrating tissues (tissues with high vascular perfusion, for example) . The slower phase is related to distribution to slowly equilibrating tissues (beta phase) and to its metabolism and excretion (gamma phase) .

Lidocaine's distribution is ultimately throughout all body tissues . In general, the more highly perfused organs will show higher concentrations of the agent . The highest percentage of this drug will be found in skeletal muscle, mainly due to the mass of muscle rather than an affinity .

Elimination Route

This drug is not believed to be absorbed when used in quantities from 1-30% .

In general, lidocaine is readily absorbed across mucous membranes and damaged skin but poorly through intact skin . The agent is quickly absorbed from the upper airway, tracheobronchial tree, and alveoli into the bloodstream . And although lidocaine is also well absorbed across the gastrointestinal tract the oral bioavailability is only about 35% as a result of a high degree of first-pass metabolism . After injection into tissues, lidocaine is also rapidly absorbed and the absorption rate is affected by both vascularity and the presence of tissue and fat capable of binding lidocaine in the particular tissues .

The concentration of lidocaine in the blood is subsequently affected by a variety of aspects, including its rate of absorption from the site of injection, the rate of tissue distribution, and the rate of metabolism and excretion . Subsequently, the systemic absorption of lidocaine is determined by the site of injection, the dosage given, and its pharmacological profile . The maximum blood concentration occurs following intercostal nerve blockade followed in order of decreasing concentration, the lumbar epidural space, brachial plexus site, and subcutaneous tissue . The total dose injected regardless of the site is the primary determinant of the absorption rate and blood levels achieved . There is a linear relationship between the amount of lidocaine injected and the resultant peak anesthetic blood levels .

Nevertheless, it has been observed that lidocaine hydrochloride is completely absorbed following parenteral administration, its rate of absorption depending also on lipid solubility and the presence or absence of a vasoconstrictor agent . Except for intravascular administration, the highest blood levels are obtained following intercostal nerve block and the lowest after subcutaneous administration .

Additionally, lidocaine crosses the blood-brain and placental barriers, presumably by passive diffusion .

Half Life

The elimination half-life of lidocaine hydrochloride following an intravenous bolus injection is typically 1.5 to 2.0 hours . Because of the rapid rate at which lidocaine hydrochloride is metabolized, any condition that affects liver function may alter lidocaine HCl kinetics . The half-life may be prolonged two-fold or more in patients with liver dysfunction .

Clearance

The mean systemic clearance observed for intravenously administered lidocaine in a study of 15 adults was approximately 0.64 +/- 0.18 L/min .

Elimination Route

The excretion of unchanged lidocaine and its metabolites occurs predominantly via the kidney with less than 5% in the unchanged form appearing in the urine . The renal clearance is inversely related to its protein binding affinity and the pH of the urine . This suggests by the latter that excretion of lidocaine occurs by non-ionic diffusion .

Pregnancy & Breastfeeding use

Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Contraindication

Hypovolaemia, complete heart block, Adam-Stokes syndrome, Wolff-Parkinson-White syndrome. Must not be applied to inflamed or injured skin.

Special Warning

Hepatic Impairment Parenteral: Dosage reduction may be needed.

Acute Overdose

Symptoms: Severe hypotension, asystole, bradycardia, apnoea, seizures, coma, cardiac arrest, resp arrest and death.

Management: Maintain oxygenation, stop convulsion and support the circulation.

Storage Condition

Store below 25°C.

Innovators Monograph

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