Atomoxetine is a selective norepinephrine reuptake inhibitor (SNRI) specifically approved for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). It is a non-stimulant medication, making it a Schedule H drug in India, not under the Narcotic Drugs and Psychotropic Substances (NDPS) Act. Its mechanism is distinct from stimulants like methylphenidate, as it does not act directly on the dopamine system in the reward pathway, resulting in a lower potential for abuse.
Adult: Initial: 40 mg daily. Increase after minimum of 3 days to target dose of 80 mg daily, as a single dose in morning or divided (morning & late afternoon/early evening). Max: 100 mg/day.
Note: Can be taken with or without food. Swallow capsule whole; do not open, chew, or crush. For patients unable to swallow capsules, the contents may be sprinkled on a small amount of soft food (e.g., applesauce, yogurt) and consumed immediately without chewing. Once-daily dosing is recommended; if experiencing side effects like somnolence, the dose can be divided.
Atomoxetine is a potent and selective inhibitor of the presynaptic norepinephrine transporter (NET) in the prefrontal cortex. By blocking NET, it increases the synaptic concentration of norepinephrine. This enhanced noradrenergic transmission in the prefrontal cortex is believed to improve attention, focus, and executive function, which are core deficits in ADHD. It has negligible affinity for other neurotransmitter receptors.
Pregnancy: Category C: Animal studies showed adverse effects. No adequate, well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to the fetus. Neonates exposed late in third trimester may experience withdrawal symptoms (irritability, feeding problems).
Driving: May cause dizziness or somnolence. Patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain the drug does not affect them adversely.
| Monoamine Oxidase Inhibitors (MAOIs) e.g., Phenelzine, Selegiline | Risk of hypertensive crisis, hyperthermia, serotonin syndrome | Contraindicated |
| Strong CYP2D6 Inhibitors (e.g., Paroxetine, Fluoxetine, Quinidine) | Markedly increases atomoxetine plasma levels (similar to a poor metabolizer). Dose adjustment required. | Major |
| Albuterol (Salbutamol) or other Beta-2 Agonists | Potentiates cardiovascular effects (increased heart rate, BP). | Moderate |
| Pressor Agents (e.g., Dopamine, Dobutamine) | Potential for increased hypertensive effect. | Moderate |
| Antihypertensives | May attenuate the effect of antihypertensives. | Moderate |