DEXTROMETHORPHAN

Question 1

What is dextromethorphan indications?

Answer 1

Temporarily use to control cough or suppress it.

ER formulations help with sleep as well

Question 2

What is maximum dosage of dextromethorphan in
Adults/ children >12 yrs?
6-11 yrs of age?
2-5 yrs of age?

Answer 2

120 mg
60 mg
30 mg

USE AS NEEDED (PRN)

Question 3

What is Dextromethorphan Contraindicated with?

Answer 3

MAOis - Mono-amine-oxidase inhibitors

DO NOT USE WITHIN 14 days of MAOis.

Question 4

List ALL the MAOis drug names

Answer 4

Phenelzine (Nardil)
Tranylcypromine (Parnate)
Isocarboxazid (Marplan)
Selegiline (Emsam, Zelapar)
Moclobemide (Aurorix, Manerix)
Rasagiline (Azilect)

Question 5

What is dextromethorphan drug-drug interactions?

Answer 5

• Strong CYP-2D6 Inhibitors will DECREASE dextromethorphan metabolism cause increasing concentration of dextromethorphan in the blood.

-SSRI / SNRI Medications with dextromethorphan will cause “ SEROTONIN SYNDROME”

• AVOID in patients who are CYP-2D6 poor metabolizers.

Question 6

Where does Dextromethorphan acts on?

Answer 6

SERETONIN re-uptake inhibitors.

@ high dose it acts on NMDA-receptor blocker (antagonist) will cause hallucinations

Question 7

What is some of “SEROTONIN SYNDROME” symptoms

Answer 7

Increase blood pressure
Hyperpyrexia (high fever 41C or 105F)
Arrythimias
Myoclonus ( Involuntary muscle movement (Con co giat co)

Question 8

what is PK of Dextromethorphan such as onset of action? Duration of action?
Half-life?

Answer 8

15-30mins
3-6 hrs
2 hrs
CYP-2D6 poor metabolizer half life took 45 hours