Product Information
Registration Status: ActiveROBITUSSIN PE SYRUP is approved to be sold in Singapore with effective from 2011-11-18. It is marketed by PFIZER PTE LTD, with the registration number of SIN14051P.
This product contains Guaifenesin 100mg/5ml, and Phenylephrine 5mg/5ml in the form of SYRUP. It is approved for ORAL use.
This product is manufactured by Fareva Richmond Inc. in UNITED STATES, andOlic (Thailand) Limited in THAILAND.
It is an Over-the-counter Medicine that can be freely obtained from any retailer
Description
An expectorant that also has some muscle relaxing action. It is used in many cough preparations. [PubChem]
Indication
Used to assist the expectoration of phlegm from the airways in acute respiratory tract infections.
Mechanism of Action
Guaifenesin may act as an irritant to gastric vagal receptors, and recruit efferent parasympathetic reflexes that cause glandular exocytosis of a less viscous mucus mixture. Cough may be provoked. This combination may flush tenacious, congealed mucopurulent material from obstructed small airways and lead to a temporary improvement in dyspnea or the work of breathing.
Pharmacokinetics
- Absorption
- Rapidly absorbed from the GI tract
- Distribution
- Metabolism
- Rapidly hydrolyzed (60% within seven hours) and then excreted in the urine, with beta-(2-methoxyphenoxy)-lactic acid as its major urinary metabolite.
- Elimination
Toxicity
LD50 1510 mg/kg (rat, oral)
Active Ingredient/Synonyms
Glyceryl guaiacolate | guaiphenesin | Hustosil | Guaifenesin |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.
Description
Phenylephrine is a sympathomimetic amine that acts predominantly on α-adrenergic receptors. It is mainly used to treat nasal congestion, but may also be useful in treating hypotension and shock, hypotension during spinal anaesthesia, prolongation of spinal anaesthesia, paroxysmal supraventricular tachycardia, symptomatic relief of external or internal hemorrhoids, and to increase blood pressure as an aid in the diagnosis of heart murmurs.
Indication
Phenylephrine is mainly used to treat nasal congestion, but may also be useful in treating hypotension and shock, hypotension during spinal anaesthesia, prolongation of spinal anaesthesia, paroxysmal supraventricular tachycardia, symptomatic relief of external or internal hemorrhoids, and to increase blood pressure as an aid in the diagnosis of heart murmurs.
Mechanism of Action
In general, α1-adrenergic receptors mediate contraction and hypertrophic growth of smooth muscle cells. α1-receptors are 7-transmembrane domain receptors coupled to G proteins, Gq/11. Three α1-receptor subtypes, which share approximately 75% homology in their transmembrane domains, have been identified: α1A (chromosome 8), α1B (chromosome 5), and α1D (chromosome 20). Phenylephrine appears to act similarly on all three receptor subtypes. All three receptor subtypes appear to be involved in maintaining vascular tone. The α1A-receptor maintains basal vascular tone while the α1B-receptor mediates the vasocontrictory effects of exogenous α1-agonists. Activation of the α1-receptor activates Gq-proteins, which results in intracellular stimulation of phospholipases C, A2, and D. This results in mobilization of Ca2+ from intracellular stores, activation of mitogen-activated kinase and PI3 kinase pathways and subsequent vasoconstriction. Phenylephrine produces its local and systemic actions by acting on α1-adrenergic receptors peripheral vascular smooth muscle. Stimulation of the α1-adrenergic receptors results in contraction arteriolar smooth muscle in the periphery. Phenylephrine decreases nasal congestion by acting on α1-adrenergic receptors in the arterioles of the nasal mucosa to produce constriction; this leads to decreased edema and increased drainage of the sinus cavities.
Pharmacokinetics
- Absorption
- Completely absorbed after oral administration. It has a reduced bioavailability (compared to pseudoephedrine) following oral administration due to significant first-pass metabolism in the intestinal wall. Compared to IV administration, bioavailability is approximately 38%. Peak serum concentrations are achieved approximately 0.75-2 hours following oral administration. Phenylephrine should be administered parenterally to achieve cardiovascular effects. Occasionally, systemic effects are observed following oral inhalation.
- Distribution
- Metabolism
- Undergoes extensive first-pass metabolism in the intestinal wall and extensive metabolism in the liver. Sulfate conjugation, primarily in the intestinal wall, and oxidative metabolism by monoamine oxidase (MAO) represent the principle routes of metabolism. Glucuronidation occurs to a lesser extent. Phenylephrine and its metabolites are mainly excreted in urine/ .
- Elimination
Active Ingredient/Synonyms
(-)-m-Hydroxy-alpha-(methylaminomethyl)benzyl alcohol | (-)-m-Hydroxy-α-(methylaminomethyl)benzyl alcohol | Benzenemethanol, 3-hydroxy-.alpha.-[(methylamino)methyl]-, (R)- | Benzenemethanol, 3-hydroxy-alpha-((methylamino)methyl)-, (R)- | Benzyl alcohol, m-hydroxy-alpha-((methylamino)methyl)-, (-)- | Fenilefrina | l-(3-Hydroxyphenyl)-N-methylethanolamine | Phenylephrine | Phenylephrinum | R(-)-Phenylephrine | Phenylephrine |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.