Dorax

Uses

Pseudoephedrine is a decongestant of the mucous membranes of the upper respiratory tract, especially the nasal mucosa, sinuses and eustachian tube. It is used for the symptomatic relief of allergic rhinitis (hay fever), vasomotor rhinitis, the common cold, influenza (flu) and ear congestion caused by ear inflammation or infection. Pseudoephedrine can also be used as a bronchodilator.

Pseudoephedrine is a stereoisomer of Ephedrine with similar but less potent pharmacological activity. It has nasal and bronchial decongestant activity.

For symptomatic relief of anxiety and tension associated with psychoneurosis and as an adjunct in organic disease states in which anxiety is manifested. Useful in the management of pruritus due to allergic conditions such as chronic urticaria and atopic and contact dermatoses, and in histamine-mediated pruritus.

As a sedative when used as premedication and following general anesthesia, hydroxyzine may potentiate meperidine and barbiturates, so their use in pre-anesthetic adjunctive therapy should be modified on an individual basis. Atropine and other belladonna alkaloids are not affected by the drug. Hydroxyzine is not known to interfere with the action of digitalis in any way and it may be used concurrently with this agent.

The effectiveness of hydroxyzine as an antianxiety agent for long term use, that is more than 4 months, has not been assessed by systematic clinical studies. The physician should reassess periodically the usefulness of the drug for the individual patient.

This is used for the symptomatic treatment of reversible bronchoconstriction associated with bronchial asthma, chronic obstructive pulmonary emphysema, chronic bronchitis and related bronchospastic disorders.

Dorax is also used to associated treatment for these conditions: Allergic Disorder, Bronchial Asthma, Common Cold, Cough, Depression, Fever, General Anesthesia Induced Hypotension, Headache, Joint Pain, Myasthenia Gravis, Narcolepsy, Nasal Congestion, Rhinorrhoea, Sore Throat, Dry coughAnxiety, Nausea and vomiting, PruritusAsthma, Bronchitis, Bronchoconstriction, Bronchospasm, Chronic Obstructive Pulmonary Disease (COPD), Chronic bronchial inflammation, Airway secretion clearance therapy, Bronchodilation

How Dorax works

Ephedrine is a direct and indirect sympathomimetic amine. Ephedrine activates adrenergic α and β-receptors as well as inhibiting norepinephrine reuptake, and increasing the release of norepinephrine from vesicles in nerve cells. These actions combined lead to larger quantities of norepinephrine present in the synapse, for longer periods of time, increasing stimulation of the sympathetic nervous system. Ephedrine's stimulation of α-1 receptors causes constriction of veins and a rise in blood pressure, stimulation of β-1 adrenergic receptors increase cardiac chronotropy and inotropy, stimulation of β-2 adrenergic receptors causes bronchodilation.

The H₁ histamine receptor is responsible for mediating hypersensitivity and allergic reactions. Exposure to an allergen results in degranulation of mast cells and basophils, which then release histamine and other inflammatory mediators. Histamine binds to, and activates, H₁ receptors, which results in the further release of pro-inflammatory cytokines, such as interleukins, from basophils and mast cells. These downstream effects of histamine binding are responsible for a wide variety of allergic symptoms, such as pruritus, rhinorrhea, and watery eyes.

Hydroxyzine is a potent inverse agonist of histamine H₁-receptors - inverse agonists are agents that are considered to have a "negative efficacy", so rather than simply blocking activity at a receptor they actively dampen its activity. Inverse agonism at these receptors is responsible for hydroxyzine's efficacy in the treatment of histaminic edema, flare, and pruritus.

Hydroxyzine is not a cortical depressant, so its sedative properties likely occur at the subcortical level of the CNS. These sedative properties allow activity as an anxiolytic. Antiemetic efficacy is likely secondary to activity at off-targets.

Theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels and reduces airway responsiveness to histamine, methacholine, adenosine, and allergen. Theophylline competitively inhibits type III and type IV phosphodiesterase (PDE), the enzyme responsible for breaking down cyclic AMP in smooth muscle cells, possibly resulting in bronchodilation. Theophylline also binds to the adenosine A2B receptor and blocks adenosine mediated bronchoconstriction. In inflammatory states, theophylline activates histone deacetylase to prevent transcription of inflammatory genes that require the acetylation of histones for transcription to begin.

Dosage

Dorax dosage

As a decongestant and symptomatic treatment for upper respiratory tract infections the recommended dose is:

Adults: 1 tablet every 4 to 6 hours, up to maximum of 240 mg in 24 hours

Children:

• 6-12 years of age: 1/2 tablet every 4 to 6 hours daily
• 2-5 years of age: 1/4 tablet every 4 to 6 hours daily
• Less than 2 years of age: This drug is not advised unless specifically recommended by a physician.

For symptomatic relief of anxiety and tension associated with psychoneurosis and as an adjunct in organic disease states in which anxiety is manifested:

• Adults: 50-100 mg q.i.d.
• Children under 6 years: 50 mg daily in divided doses
• Over 6 years: 50-100 mg daily in divided doses

For use in the management of pruritus due to allergic conditions such as chronic urticaria and atopic and contact dermatoses, and in histamine-mediated pruritus:

• Adults: 25 mg t.i.d. or q.i.d.
• Children under 6 years: 50 mg daily in divided doses
• Over 6 years: 50-100 mg daily in divided doses

As a sedative when used as a premedication and following general anesthesia:

• Adults: 50-100 mg
• Children: 0.6 mg/kg of body weight

When treatment is initiated by the intramuscular route of administration, subsequent doses may be administered orally. As with all medications, the dosage should be adjusted according to the patient's response to therapy.

Dosages are adjusted to maintain serum theophylline concentrations that provide optimal relief of symptoms with minimal side effects. Most of the controlled release preparations may be administered every 12 hours in adults while administration every 8 hours may be necessary in some children with markedly rapid hepatic metabolism of theophylline. The recommended dosages for achieving serum theophylline concentrations within the accepted therapeutic range is as follow:

• 1-6 months: 10mg/Kg/day
• 6 months-1 year: 15mg/Kg/day
• 1-9 years: 24mg/Kg/day
• 10-16 years: 18mg/Kg/day
• Adults: 10-15mg/Kg/day

May be taken with or without food.

Side Effects

Serious adverse effects associated with the use of Pseudoephedrine are rare. Symptoms of central nervous system excitation may occur, including sleep disturbances and, rarely, hallucinations have been reported. Skin rashes, with or without irritation, have occasionally been reported.

Side effects reported with the administration of hydroxyzine hydrochloride are usually mild and transitory in nature.

Anticholinergic: Dry mouth.

Central Nervous System: Drowsiness is usually transitory and may disappear in a few days of continued therapy or upon reduction of the dose. Involuntary motor activity including rare instances of tremor and convulsions have been reported, usually with doses considerably higher than those recommended. Clinically significant respiratory depression has not been reported at recommended doses.

The following side effects have been observed:

Gastrointestinal: Nausea, vomiting, epigastric pain and diarrhoea.

Central nervous system: Headache, irritability, restlessness, insomnia, muscles twitching.

Cardiovascular: Palpitation, tachycardia, hypotension. circulatory failure.

Respiratory: Tachypnoea.Renal: Potentiation of diuresis.

Others: Alopecia, hyperglycemia, rash etc.

Toxicity

Patients experiencing an overdose of ephedrine will present with rapidly increasing blood pressure. Manage overdose with blood pressure monitoring, and possibly the administration of parenteral antihypertensives. The LD₅₀ in mice after oral administration is 785mg/kg, after intraperitoneal administration if 248mg/kg, and after subcutaneous administration is 425mg/kg.

The oral LD₅₀ is 840 mg/kg in rats and 400 mg/kg in mice.

Overdose from hydroxyzine is most commonly characterized by hypersedation, but may also manifest as convulsions, stupor, nausea, and vomiting. In cases of overdose, consider the induction of vomiting and the use of gastric lavage. Other treatment should involve general symptomatic and supportive care. Hypotension may be controlled by intravenous fluids and pressors, and caffeine and sodium benzoate injection may be used to counteract any observed CNS depressant effects. Hemodialysis is unlikely to provide any benefit in the treatment hydroxyzine overdose.

Symptoms of overdose include seizures, arrhythmias, and GI effects.

Precaution

Although Pseudoephedrine has virtually no pressor effects in normotensive patients, it should be used with caution in patients suffering mild to moderate hypertension. As with other sympathomimetic agents, Pseudoephedrine should be used with caution in patients with hypertension, heart disease, diabetes, hyperthyroidism, elevated intraocular pressure and prostatic enlargement. Caution should be exercised when using the product in the presence of severe hepatic impairment or moderate to severe renal impairment.

Patient with porphyria, suffering from glaucoma, bladder outflow obstruction, decreased GI motility, myasthenia gravis, or dementia; with known predisposing factor to cardiac arrhythmia, including electrolyte imbalance, increased potential for convulsions, and pre-existing heart disease. Do not admin via SC, IV, or intra-arterial inj. Renal and hepatic impairment.

Careful consideration is needed for various interacting drugs and physiologic conditions that can alter Theophylline clearance. Dosage adjustment is required prior to initiation of Theophylline therapy, prior to increases in Theophylline dose, and during follow up. The dose of Theophylline selected for initiation of therapy should be low and, if tolerated, increased slowly over a period of time.

Interaction

Additive or may potentiate CNS depressant effects of opiates or other analgesics, barbiturates or other sedatives, and anaesth. MAOIs and TCAs potentiate antimuscarinic effects.

Allopurinol, cimetidine, norfloxacin, ciprofloxacin, erythromycin, oral contraceptives and propranolol increase serum theophylline levels. Phenytoin, methotrexate and rifampicin lead to decreased serum theophylline levels

Volume of Distribution

Oral ephedrine has an average volume of distribution of 215.6L.

The mean volume of distribution is 16.0 ± 3.0 L/kg. Higher concentrations are found in the skin than in the plasma.

• 0.3 to 0.7 L/kg

Elimination Route

Oral ephedrine reaches an average C_max of 79.5ng/mL, with a T_max of 1.81h, and a bioavailability of 88%.

The absolute bioavailability of hydroxyzine has not been ascertained, as intravenous formulations are unavailable due to a risk of hemolysis. Hydroxyzine is rapidly absorbed from the gastrointestinal tract upon oral administration, reaching its maximum plasma concentration (T_max) approximately 2 hours following administration.

Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form.

Half Life

Oral ephedrine has a plasma elimination half life of approximately 6 hours, but there is a large degree of inter-patient variability.

The half-life of hydroxyzine is reportedly 14-25 hours, and appears to be, on average, shorter in children (~7.1 hours) than in adults (~20 hours). Elimination half-life is prolonged in the elderly, averaging approximately 29 hours, and is likely to be similarly prolonged in patients with renal or hepatic impairment.

8 hours

Clearance

Oral ephedrine has a clearance of 23.3L/h but there is a high degree of inter-patient variability.

Clearance of hydroxyzine has been reported to be 31.1 ± 11.1 mL/min/kg in children and 9.8 ± 3.3 mL/min/kg in adults.

• 0.29 mL/kg/min [Premature neonates, postnatal age 3-15 days]
• 0.64 mL/kg/min [Premature neonates, postnatal age 25-57 days]
• 1.7 mL/kg/min [Children 1-4 years]
• 1.6 mL/kg/min [Children 4-12 years]
• 0.9 mL/kg/min [Children 13-15 years]
• 1.4 mL/kg/min [Children 16-17 years]
• 0.65 mL/kg/min [Adults (16-60 years), otherwise healthy non-smoking asthmatics]
• 0.41 mL/kg/min [Elderly (>60 years), non-smokers with normal cardiac, liver, and renal function]
• 0.33 mL/kg/min [Acute pulmonary edema]
• 0.54 mL/kg/min [COPD >60 years, stable, non-smoker >1 year]
• 0.48 mL/kg/min [COPD with cor pulmonale]
• 1.25 mL/kg/min [Cystic fibrosis (14-28 years)]
• 0.31 mL/kg/min [Liver disease cirrhosis]
• 0.35 mL/kg/min [acute hepatitis]
• 0.65 mL/kg/min [cholestasis]
• 0.47 mL/kg/min [Sepsis with multi-organ failure]
• 0.38 mL/kg/min [hypothyroid]
• 0.8 mL/kg/min [hyperthyroid]

Elimination Route

Ephedrine is mainly eliminated in the urine. Approximately 60% is eliminated as the unmetabolized parent compound, 13% as benzoic acid conjugates, and 1% as 1,2-dihydroxypropylbenzene.

Approximately 70% of hydroxyzine's active metabolite, cetirizine, is excreted unchanged in the urine. The precise extent of renal and fecal excretion in humans has not been determined.

Theophylline does not undergo any appreciable pre-systemic elimination, distributes freely into fat-free tissues and is extensively metabolized in the liver. Renal excretion of unchanged theophylline in neonates amounts to about 50% of the dose, compared to about 10% in children older than three months and in adults.

Pregnancy & Breastfeeding use

Although Pseudoephedrine has been in widespread use for many years without apparent ill consequence, there are no specific data on its use during pregnancy. Caution should therefore be exercised by balancing the potential benefit of treatment to the mother against any possible hazards to the developing foetus. Pseudoephedrine is excreted in breast milk in small amounts but the effect of this on breast-fed infants is not known.

Pregnancy Category C. Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Nursing mothers: It is not known whether this drug is excreted in human milk. Since many drugs are so excreted, hydroxyzine should not be given to nursing mothers.

Pregnancy: It is not known whether Theophylline can cause foetal harm when administered to pregnant woman.Xanthines should be given to a pregnant woman only if clearly needed.

Nursing mother: Theophylline is excreted into breast milk and may cause irritability or other signs of mild toxicity in nursing human infants. Serious adverse effects in the infant are unlikely unless the mother has toxic serum Theophylline concentrations.

Contraindication

Pseudoephedrine is contraindicated in-

• Hypersensitivity of individuals to this drug
• Severe hypertension and coronary artery disease
• Concurrent use of Mono Amine Oxidase Inhibitor (MAOI) drugs

Hydroxyzine, when administered to the pregnant mouse, rat, and rabbit, induced fetal abnormalities in the rat and mouse at doses substantially above the human therapeutic range. Clinical data in human beings are inadequate to establish safety in early pregnancy. Until such data are available, hydroxyzine is contraindicated in early pregnancy. Hydroxyzine is contraindicated for patients who have shown a previous hypersensitivity to it.

Hypersensitivity to xanthine derivatives. It is also contraindicated in patients with active peptic ulcer disease and in individuals with underlying seizure disorders (unless receiving appropriate anti-convulsing medication).

Theophylline should not be administered concurrently with other xanthine. Use with caution in patients with hypoxemia, hypertension, or those with history of peptic ulcer. Do not attempt to maintain any dose that is not tolerated.

Special Warning

Renal Impairment: Moderate to severe: Reduce dose by 50%.

Hepatic Impairment: Oral: Reduce total daily dose by 33%.

Geriatric use: A determination has not been made whether controlled clinical studies of hydroxyzine included sufficient numbers of subjects aged 65 and over to define a difference in response from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

The extent of renal excretion of hydroxyzine has not been determined. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selections. Sedating drugs may cause confusion and over sedation in the elderly; elderly patients generally should be started on low doses of hydroxyzine and observed closely.

Acute Overdose

As with other sympathomimetic agents, symptoms of overdosage include irritability, restlessness, tremor, convulsions, palpitations, hypertension and difficulty in micturition. Necessary measures should be taken to maintain and support respiration and control convulsions. Gastric lavage should be performed if indicated. If desired, the elimination of Pseudoephedrine can be accelerated by acid diuresis or by dialysis.

Symptoms: Excessive sedation, hypotension (rare).

Management: Symptomatic and supportive treatment. Empty stomach immediately by inducing emesis or by gastric lavage. Admin IV fluids and norepinephrine or metaraminol if hypotension occurs.

Symptoms may include nausea, vomiting, gastrointestinal irritation, cramps, convulsions, tachycardia & hypotension. The stomach contents should be emptied & supportive measures employed to maintain circulation, respiration & fluid & electrolyte balance. Electrocardiographic monitoring should be carried out & in severe poisoning charcoal haemoperfusion should be used.

Storage Condition

Store between 15-30° C. Protect from light.

Store in a cool and dry place, protect from light and moisture. Keep out of the reach of children

Innovators Monograph

You find simplified version here Dorax