Product Information
Registration Status: ActiveDIMETAPP LIQUID is approved to be sold in Singapore with effective from 2001-02-26. It is marketed by PFIZER PTE LTD, with the registration number of SIN11459P.
This product contains Brompheniramine 2mg/5ml, and Phenylephrine 5mg/5ml in the form of ELIXIR. It is approved for ORAL use.
This product is manufactured by OLIC (Thailand) LTD in THAILAND.
It is a Pharmacy Only Medicine that can be obtained from a pharmacist at a retail pharmacy.
Description
Histamine H1 antagonist used in treatment of allergies, rhinitis, and urticaria. [PubChem]
Indication
For the treatment of the symptoms of the common cold and allergic rhinitis, such as runny nose, itchy eyes, watery eyes, and sneezing.
Mechanism of Action
Brompheniramine works by acting as an antagonist of the H1 histamine receptors. It also functions as a moderately effective anticholingeric agent, likely an antimuscarinic agent similar to other common antihistamines such as diphenhydramine. Its effects on the cholinergic system may include side-effects such as drowsiness, sedation, dry mouth, dry throat, blurred vision, and increased heart rate.
Pharmacokinetics
- Absorption
- Antihistamines are well absorbed from the gastrointestinal tract after oral administration.
- Distribution
- Metabolism
- Hepatic (cytochrome P-450 system), some renal.
- Elimination
Toxicity
Oral, rat: LD50 = 318 mg/kg. Signs of overdose include fast or irregular heartbeat, mental or mood changes, tightness in the chest, and unusual tiredness or weakness.
Active Ingredient/Synonyms
[3-(4-Bromo-phenyl)-3-pyridin-2-yl-propyl]-dimethyl-amine | 1-(P-Bromophenyl)-1-(2-pyridyl)-3-dimethylaminopropane | 2-(P-Bromo-alpha-(2-dimethylaminoethyl)benzyl)pyridine | 3-(4-Bromophenyl)-N,N-dimethyl-3-(2-pyridinyl)-1-propanamine | 3-(P-Bromophenyl)-3-(2-pyridyl)-N,N-dimethylpropylamine | BPN | Bromfeniramina | Brompheniramin | Bromphéniramine | Brompheniraminum | Brompheniramine |
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.