Brand Name : KOFTAB-D
Generic Name : Dextromethorphan 30 mg + Phenylephrine 10 mg + Triprolidine 5 mg
Preparation : Tablet
Pharmacological Category : Cough Suppressant
Mechanism of Action (MOA)
Dextromethorphan HBr is a cough suppressant, which has a central action on the cough center in the medulla. It is also an antagonist of N-methyl-D-aspartate (NMDA) receptors. It has no analgesic properties and has little sedative activities.
Phenylephrine HCl is a selective α1 agonist. It constricts the nasal blood vessels, thereby decreasing blood flow to the sinusoidal vessels, leading to decreased mucosal edema.
Triprolidine is an alkylamine derivative. It is a sedative antihistamine with antimuscarinic and mild sedative effects.
- Absorption : Rapidly absorbed from the gastrointestinal tract
- Onset of Action : 30 minutes
- Metabolism : Liver
- Excretion : Urine
- Absorption : Completely absorbed from the gastrointestinal tract
- Bioavailability : Approximately 38%
Peak Plasma Concentration : 0.75 to 2 hours
- Onset of Action : 15 to 20 minutes (nasal decongestion)
- Duration : 2 to 4 hours
- Distribution : Peripheral tissues, brain (minimal)
- Metabolism : Extensively metabolised in the intestinal wall; moderately in liver
- Elimination Half-life : 2 to 3 hours
- Excretion : Urine (80 to 86%)
- Absorption : Absorbed from the gastrointestinal tract
- Elimination Half-life : 3 to 5 hours or more
- Excretion : Urine
Indications and Dosage
Non-productive Cough : One tablet of KOFTAB-D twice daily
COMMON : Drowsiness, lassitude, dizziness, incoordination, headache, psychomotor impairment, dry mouth, thickened respiratory tract secretions, blurred vision, urinary difficulty or retention, constipation, increased gastric reflux, nervousness
OCCASSIONAL : Nausea, vomiting, diarrhoea, epigastric pain, palpitation, arrhythmias
REPORTED : Convulsions, sweating, myalgia, paresthesias, extrapyramidal effects, tremor, sleep disturbance, depression, confusion, tinnitus, hypotension, hair loss
RARE : Rashes and hypersensitivity reaction, agranulocytosis, leucopenia, haemolytic anemia, thrombocytopenia
Hypersensitivity to dextromethorphan, phenylephrine or triprolidine, concurrent use with MAO inhibitors, cardiac disease, high blood pressure, thyroid disease, difficulty in urination, prostatic hyperplasia, asthmatic attacks
Warnings / Precautions
- Should not be given to patients at risk of developing respiratory failure; caution is needed in patients with a history of asthma and it should not be given during an acute attack. Care in patients with bronchitis, emphysema or in other conditions where chronic or persistent cough occurs.
- Use cautiously in patients with history of angina, severe atherosclerosis, septic shock, autonomic dysfunction, thyroid disease, diabetes mellitus, hypertension, heart disease, prostatic hyperplasia, urinary retention, angle-closure glaucoma, pyloroduodenal obstruction, epilepsy, renal or hepatic impairment, elderly patients, nursing mother.
- Patients should not drive or operate machinery and should avoid alcohol.
- Children under 12 years of age should not use phenylephrine for nasal congestion associated with colds and hay fever.
- Severe and sometimes fatal reactions have been reported after use of dextromethorphan in patients receiving MAOIs.
- Dextromethorphan has possibility of interactions with amiodarone, haloperidol, propafenone, quinidine, SSRIs and thioridazone as all of these drugs are primarily metabolized by the cytochrome P450 isoenzyme CYP2D6.
- Risk of cardiac irritability and arrhythmias is increased with general anesthetics (cyclopropane or halogenated hydrocarbon).
- Concomitant use of phenylephrine with MAO inhibitors potentiates the cardiac and blood pressure effects.
- Oxytocic drugs may potentiate blood pressure effect of phenylephrine with risk of hemorrhagic stroke.
- Agents that may potentiate pressure effect of phenylephrine include α2 agonists eg. clonidine, β blockers, tricyclic antidepressants, corticosteroids, atropine and norepinephrine reuptake inhibitors eg. atomoxetine.
- Agents that may reduce the pressure effect of phenylephrine include benzodiazepines, diuretics eg. frusemide, phosphodiesterase type 5 inhibitors.
- Alpha adrenergic blocking agent eg. phentolamine mesylate, amiodarone, phenothiazines may block the effects of both agents; excessive rise in BP may occur with ergot alkaloids.
- Digoxin can sensitize myocardium when given along with phenylephrine.
- Triprolidine enhances the sedative effects of CNS depressants including alcohol, barbiturates, hypnotics, opioid analgesics, anxiolytic sedatives, antipsychotics.
- Additive antimuscarinic action with other antimuscarinic drugs such as atropine and some antidepressants (both tricyclics and MAOIs)
- Triprolidine may mask the warning signs of damage caused by ototoxic drugs such as aminoglycosides.
- Triprolidine may suppress the cutaneous histamine response to allergen extracts and should be stopped several days before skin testing.
Pregnancy Category : C
KOFTAB-D : A box of 30 strips, each strip of 10 tablets