Showmin (ANTIHISTAMINICES)

Uses

• Perenial and seasonal allergic rhinitis
• Vasomotor rhinitis
• Allergic conjunctivitis due to inhalant allergens and foods
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Amelioration of allergic reactions to blood or plasma
• Cold urticaria
• Dermatographism

As therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after the acute manifestations have been controlled.

Showmin (ANTIHISTAMINICES) is also used to associated treatment for these conditions: Allergic Reactions caused by Transfusions, Anaphylaxis, Angioedema and urticaria, Cold urticaria, Conjunctivitis allergic caused by Food Allergy, Conjunctivitis allergic caused by inhalant allergens, Perennial Allergic Rhinitis (PAR), Pruritus, Seasonal Allergic Rhinitis, Serotonin Syndrome, Vasomotor Rhinitis, Dermatographism, Appetite stimulation

How Showmin (ANTIHISTAMINICES) works

Showmin (ANTIHISTAMINICES) appears to exert its antihistamine and antiserotonin effects by competing with free histamine and serotonin for binding at their respective receptors. Antagonism of serotonin on the appetite center of the hypothalamus may account for cyproheptadine's ability to stimulate the appetite.

Dosage

Showmin (ANTIHISTAMINICES) dosage

Pediatric Patients:Age 2 To 6 Years:

• The total daily dosage for pediatric patients may be calculated on the basis of body weight or body area using approximately 0.25 mg/kg/day or 8 mg per square meter of body surface (8 mg/m2).
• The usual dose is 2 mg two or three times a day, adjusted as necessary to the size and response of the patient. The doe is not to exceed 12 mg a day.

Age 7 To 14 Years:

• The usual dose is 4 mg two or three times a day adjusted as necessary to the size and response of the patient. The dose is not to exceed 16 mg a day.

Adults: The total daily dose for adults should bot exceed 0.5 mg/kg/day. The therapeutic range is 4 to 20 mg a day, with the majority of patients requiring 12 to 16 mg a day. An occasional patient may require as much as 32 mg a day for adequate relief. It is suggested that dosage be initiated with 4 mg three times a day and adjusted according to the size and response of the patient.

Side Effects

Confusion, disturbed coordination, dizziness, excitation, euphoria, hallucinations, headache, hysteria, insomnia, irritability, nervousness, restlessness, sedation, seizure, sleepiness, tremor, vertigo, hypotension, palpitation, tachycardia, abdominal pain, anorexia, increased appetite, constipation, diarrhoea, nausea, vomiting, xerostomia, difficult urination, urinary retention, urinary frequency, blurred vision, diplopia, tinnitus, acute labyrinthitis, nasal congestion, pharyngitis, thickening bronchial secretion, paraesthesia, hepatitis, cholestasis, hepatic failure, jaundice, angioedema, photosensitivity, rash, urticaria, fatigue, chills, diaphoresis.

Toxicity

Overdosage with cyproheptadine is likely to result in significant sedation - although paradoxical stimulation has been noted in pediatric patients - and anticholinergic adverse effects such as dry mouth and flushing. Most patients appear to recover without incident, as a review of cyproheptadine overdose cases in Hong Kong found the majority of patients had no or mild symptoms following intentional overdose.

In the event of overdosage with cyproheptadine, prescribing information recommends the induction of vomiting (if it has not occurred spontaneously) using syrup of ipecac. Gastric lavage and activated charcoal may also be considered. Vasopressors may be used to treat hypotension and intravenous physostigmine salicylate may be considered for the treatment of significant CNS symptoms depending on the clinical picture.

Precaution

Patient with CV disease including HTN and ischaemic heart disease, increased intraocular pressure, asthma or other chronic breathing disorders, thyroid dysfunction. Pregnancy.

Interaction

May have additive effects with CNS depressants e.g. hypnotics, sedatives, tranquilizers, antianxiety agents. MAOIs prolong and intensify the anticholinergic effects of antihistamines.

Food Interaction

• Avoid alcohol. Co-administration with alcohol may potentiate the sedative effects of cyproheptadine.

[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.

Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.

Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Showmin (ANTIHISTAMINICES) Drug Interaction

Moderate: diphenhydramine, diphenhydramine, duloxetine, duloxetine, cetirizine, cetirizineUnknown: fluticasone nasal, fluticasone nasal, polyethylene glycol 3350, polyethylene glycol 3350, montelukast, montelukast, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, cholecalciferol, cholecalciferol, ondansetron, ondansetron

Showmin (ANTIHISTAMINICES) Disease Interaction

Moderate: anticholinergic effects, asthma/COPD, cardiovascular, renal/liver disease

Elimination Route

A single study examining the difference in absorption of orally administered versus sublingually administered cyproheptadine in five healthy males demonstrated a mean C_max of 30.0 mcg/L and 4.0 mcg/L, respectively, and a mean AUC of 209 mcg.h/L and 25 mcg.h/L, respectively. The T_max of orally and sublingually administered cyproheptadine was 4 hours and 9.6 hours, respectively.

Elimination Route

Approximately 2-20% of the radioactivity from an orally administered radio-labeled dose of cyproheptadine is excreted in the feces, of which approximately 34% is unchanged parent drug (less than 5.7% of the total dose). At least 40% of radioactivity is recovered in the urine.

Pregnancy & Breastfeeding use

Pregnancy 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

Narrow-angle glaucoma, bladder neck obstruction, pyloroduodenal obstruction, symptomatic prostatic hyperplasia, stenosing peptic ulcer. Concurrent use with MAOIs. Debilitated elderly, newborn or premature infants. Lactation.

Acute Overdose

Symptoms: CNS depression to stimulation, atropine-like (e.g. dry mouth, fixed, dilated pupils, flushing) and GI symptoms.

Management: Induce vomiting with syrup of ipecac. If unable to vomit, perform gastric lavage followed by activated charcoal. Saline cathartics may be useful for quick dilution of bowel content by osmosis. Vasopressors may be used for hypotension.

Storage Condition

Store between 15-30°C.

Innovators Monograph

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