Dextromethorphan

DELSYM

What it isNMDA antagonist and sigma-1 agonist; cough, and with bupropion or quinidine for depression and pseudobulbar affect.

Why this oneIts NMDA action gives rapid antidepressant effect when metabolism is blocked by a partner drug.

What limits itSerotonin syndrome with MAOIs and serotonergic drugs. CYP2D6-dependent, and it is abused at high dose.

FDA-approved for

FDA dosing	Population	Start	Target	Max
Cough — temporary relief of cough due to minor throat and bronchial irritation (as with a cold)	Adults & children ≥12 yr	2 softgels q6–8h PRN	2 softgels q6–8h PRN	8 softgels/24 hr

Renal Undefined

Hepatic Undefined

Do not exceed 8 softgels in any 24-hour period.

Do not use in children under 12 years of age — this adult product is not intended for them.

Ask a doctor before use: cough with too much phlegm (mucus), or chronic cough as with smoking, asthma, or emphysema
Stop use and ask a doctor if cough lasts >7 days, comes back, or occurs with fever, rash, or persistent headache (possible serious condition)

Pregnancy If pregnant, ask a health professional before use.

Lactation If breast-feeding, ask a health professional before use.

NO BOXED WARNINGS

Principal riskSerotonin syndrome with MAOIs; abuse at high dose