Table 3.

Drugs with Unusual Effects in Autonomic Failure

Drugs	Effects
Pressor effect
Phenylephrine	Markedly increases blood pressure (even eye drops) 14
Norepinephrine	Markedly Increases blood pressure
Vasopressin	Markedly Increases blood pressure 63
Atomoxetine	Excessive pressor effect (~25 mmHg) in MSA but not pure autonomic failure
Octreotide	Low dose (12.5mg) may increase blood pressure for several hours
Saline	Increases blood pressure
Oxymetazoline	Increases blood pressure
NSAID (indomethacin)	Increases blood pressure by 5-30 mmHg64
Ephedrine	Increases blood pressure 35
Clonidine	High dose (> 0.4 mg) paradoxically increases rather than lowers blood pressure 65.
Depressor effect
Salbutamol/terbutaline	Can reduce supine systolic blood pressure up to 50%66
Insulin IV	Decreases blood pressure Tizanidine Depressor first, then pressor (overshoot) when drug levels are gone
Propranolol	Usually little effect on blood pressure
Narcotics/Barbiturates	Depressor
Atropine	Large IV dose (3mg) may transiently decrease blood pressure because of the drug’s small α-1 antagonist effect, especially if α agonist is being administered.
Dexmedetomidine	Blood pressure fall may not always occur
Dopamine	May be depressor
Nitrates	Depressor effect, with significant blood pressure drop
Chronotropic effect
Isoproterenol	6 fold β-1 hypersensitivity and 17 fold β-2 hypersensitivity66
Epinephrine	Increases heart rate more than blood pressure -may be depressor
Pindolol	Increases HR 5-20 beats/min with mild elevation of blood pressure
Miscellaneous effect
Lidocaine	Toxic levels and seizures if plasma levels increase with posture change

HR, heart rate; MSA, multiple system atrophy; NSAID, non-steroidal anti-inflammatory drug.