Pill power: new drug combo may ease sleep apnea without a mask

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion criteria: * Ages 21-70 years * Diagnosed OSA or clinically-suspected OSA * Not using CPAP (\>1 month). Exclusion criteria: * Any uncontrolled medical condition * Current use of the medications under investigation * Use of medications expected to stimulate or depress respiration (including opioids, barbiturates, doxapram, almitrine, theophylline, 4-hydroxybutanoic acid). * Current use of hypnotic medications (trazodone, eszopiclone, benzodiazepines). * Current use of SNRIs/SSRIs or anticholinergic medications. * Conditions likely to affect obstructive sleep apnea physiology: neuromuscular disease or other major neurological disorder, heart failure (also below), or any other unstable major medical condition. * Respiratory disorders other than sleep disordered breathing: chronic hypoventilation/hypoxemia (awake SaO2 \< 92% by oximetry) due to chronic obstructive pulmonary disease or other respiratory conditions. * Other sleep disorders: periodic limb movements (periodic limb movement arousal index \> 10/hr), narcolepsy, or parasomnias. * Contraindications for atomoxetine and oxybutynin, including: * hypersensitivity to study drugs (angioedema or urticaria) * pheochromocytoma * use of monoamine oxidase inhibitors * benign prostatic hypertrophy, urinary retention * untreated narrow angle glaucoma * bipolar disorder, mania, psychosis * history of major depressive disorder (age\<24). * history of attempted suicide or suicidal ideation within one year prior to screening * clinically significant constipation, gastric retention * pre-existing seizure disorders * clinically-significant kidney disorders (eGFR\<60 ml/min/1.73m2) * clinically-significant liver disorders * clinically-significant cardiovascular conditions * severe hypertension (SBP\>180 mmHg or DBP\>110 mmHg measured at baseline) * cardiomyopathy (LVEF\<50%) or heart failure * advanced atherosclerosis * history of cerebrovascular events * history of cardiac arrhythmias e.g., atrial fibrillation, QT prolongation * other serious cardiac conditions that would raise the consequences of an increase in blood pressure or heart rate * myasthenia gravis * pregnancy/breast-feeding * Allergy to lidocaine (Aim 2 only) * Claustrophobia * Pregnancy or nursing