Sympathomimetics Drugs
The sympathomimetics constitute a very important group of drugs used for cardiovascular, respiratory, and other conditions.
They are readily divided into subgroups on the basis of their spectrum of action (α-, β-, or dopamine-receptor affinity) or mode of action (direct or indirect).
Sympathomimetics Drugs
Subclass
Noncatecholamines
Phenylephrine
- Mechanism of Action
α1, α2 agonist
- Clinical Applications
Decongestant, mydriatic, neurogenic hypotension
- Pharmacokinetics
Oral, inhalant, topical, and parenteral • Duration: 15–60 min
- Toxicities, Interactions
Hypertension, stroke, myocardial infarction
Subclass
Noncatecholamine β-selective
Albuterol, metaproterenol, terbutaline
- Mechanism of Action
β2 agonist
- Clinical Applications
Prompt onset for acute bronchospasm
- Pharmacokinetics
Inhalant via aerosol canister • Duration: 2–6 h
- Toxicities, Interactions
Tachycardia, tremor
Subclass
Indirect-acting phenylisopropylamines
Amphetamine,
methamphetamine
- Mechanism of Action
Displaces stored catecholamines from nerve endings
- Clinical Applications
Anorexiant, ADHD, narcolepsy
- Pharmacokinetics
Inhalant via aerosol
Oral and parenteral • Duration: ≥4–6 h
- Toxicities, Interactions
High addiction liability. Paranoia, aggression; insomnia; hypertension
Subclass
Cocaine
Cocaine
- Mechanism of Action
Blocks norepinephrine reuptake (NET) and dopamine reuptake (DAT)
- Clinical Applications
Local anesthetic with intrinsic hemostatic action
- Pharmacokinetics
Parenteral only ,Duration: 2 h
- Toxicities, Interactions
Very high addiction ,liability. Hypertension, arrhythmias, seizures
Subclass
Tyramine
Tyramine
- Mechanism of Action
Displaces stored catecholamines
- Clinical Applications
No clinical use but found in fermented foods
- Pharmacokinetics
Parenteral only ,Duration: 2 h
- Toxicities, Interactions
Hypertension, arrhythmias, stroke, myocardial infarction.