Dextromethorphan is used to provide relief from dry, non-productive cough (a type of cough which does not produce phlegm) due to minor irritation occurring with cold or inhaled irritants.
Take Dextromethorphan exactly as directed by your doctor or according to the instructions on the label. Do not take more than instructed by your doctor.
You may take this medicine with or without food. Try to take it at the same time each day.
Dextromethorphan is available as a liquid-filled capsule, caplet, oral solution, syrup, lozenge, or extended-release oral suspension.
If you are taking an extended-release oral suspension, shake the bottle well before you take it to ensure that the liquid is evenly mixed.
If you are taking an oral solution, syrup, or extended-release oral suspension, use the measuring spoon or cup provided to measure your dose.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Alert your doctor if you have the following conditions:
- sudden and serious asthma attacks
- lung disease
- long-standing cough as occurs with smoking
- cough with too much phlegm
- liver disease
as Dextromethorphan may not be suitable for you.
Do not take this medicine if you are currently taking or have taken medicines to treat depression such as monoamine oxidase inhibitor (MAOI) and selective serotonin reuptake inhibitor (SSRI) or medicines to treat Parkinson's disease (a disorder that affects the movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement and impaired balance or walking). Please see the section "Can I take this with other medicines?" below for more information.
Inform your doctor if you have the following conditions:
- history of asthma
- current or history of substance use disorder including alcohol abuse
- mental illness e.g. major depression
Let your doctor know if you are pregnant or breastfeeding.
Be sure to check with your doctor or pharmacist before giving Dextromethorphan to a child or debilitated patient (a person who is physically or mentally weak usually due to illness or old age). Children and debilitated patients may be more sensitive to the side effects.
Individuals who are poor metabolisers of CYP2D6 may experience enhanced or prolonged side effects of Dextromethorphan. If you know you have this gene type, inform your doctor.
Inform your doctor if your symptoms do not improve within 7 days, or if it is accompanied by fever, rash, or persistent headache.
Dextromethorphan may cause dizziness or drowsiness. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: diarrhoea, nausea, vomiting, constipation, stomach pain, confusion, excitement, restlessness, nervousness, convulsions, slow or ineffective breathing and rash.
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not take Dextromethorphan if you are taking any of these medicines:
- medicines for depression called monoamine oxidase inhibitors (MAOIs) e.g. isocarboxazid, phenelzine, and tranylcypromine (or have taken them in the last 14 days), selective serotonin reuptake inhibitors (SSRIs) e.g. fluoxetine, tricyclic antidepressants (TCAs) e.g. imipramine
- medicines to treat Parkinson's disease (a disorder that affects the movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement and impaired balance or walking)
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for heart disease e.g. quinidine, amiodarone
- medicines for mood disorders e.g. haloperidol, thioridazine
- strong painkillers e.g. oxycodone
- medicines for cold or allergy e.g. diphenhydramine
This list does not include all medicines that may interact with Dextromethorphan.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.
Avoid alcohol.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.
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