Origin and Chemical Structure
Platyphylline (Platyphyllinum) is an alkaloid isolated from the broadleaf ragwort plant (Senecio platyphyllus). Chemically, the drug is a methylpyrrolizidine derivative.
A key pharmacokinetic feature of the drug is that it is a tertiary ammonium base. Because of this, platyphylline is lipophilic: it is well absorbed in the gastrointestinal tract when taken orally and freely crosses the blood-brain barrier (BBB) into the central nervous system.
Mechanism of Action
The drug possesses a unique dual mechanism of action, which distinguishes it from the prototype of the group, atropine:
- Muscarinic-blocking action. Platyphylline is a non-selective antagonist of muscarinic acetylcholine receptors (acting similarly to atropine, but significantly weaker). Within this mechanism, it acts as an antisecretory agent: it suppresses hydrochloric acid secretion by gastric parietal cells.
- Direct myotropic antispasmodic action. The drug can directly affect the smooth muscle of internal organs and blood vessels, causing relaxation independently of cholinergic innervation.
Pharmacological Effects
Due to the combination of receptor-mediated and myotropic mechanisms, platyphylline effectively relieves spasms of smooth muscle organs.
An important systemic effect that distinguishes it from many other anticholinergics is its impact on the vascular bed. The drug causes vasodilation, resulting in a moderate decrease in blood pressure (BP).
Indications for Use
In clinical practice, the drug is used as a salt — platyphylline hydrotartrate. The main indications include:
- Spasms of abdominal smooth muscle organs (including relief of renal colic).
- Peptic ulcer disease of the stomach and duodenum (as an antispasmodic and antisecretory agent reducing hydrochloric acid production).
- Cerebral vascular spasms.
- Peripheral vascular spasms.
Dosage Forms and Administration
The drug is available in a wide range of dosage forms for enteral and parenteral use:
- Powder;
- Tablets, 0.005 g;
- Oral solution (drops) 0.5% — 15 ml;
- Solution in ampoules 0.2% — 1 ml;
- Suppositories, 0.005 g.
Administration Rules:
- Oral: administered strictly before meals, 0.003–0.005 g 2–3 times a day. As drops — 10–15 drops of the 0.5% solution 2–3 times a day.
- Parenteral: subcutaneous (SC) injection of 1–2 ml of 0.2% solution.
Dosage limits for oral administration: Maximum single dose (MSD) is 0.01 g; Maximum daily dose (MDD) is 0.03 g.