Origin and chemical structure
Platyphylline (Platyphyllinum) is an alkaloid isolated from the broad-leaved ragwort plant (Senecio platyphyllus). Structurally, the drug is a methylpyrrolizidine derivative.
A key pharmacokinetic feature of the drug is that it is a tertiary ammonium base. Due to 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 receptor blocking action. Platyphylline is a non-selective muscarinic receptor antagonist (acts similarly to atropine, but significantly weaker). Within this mechanism, it acts as an antisecretory agent: it inhibits hydrochloric acid secretion by parietal cells of the stomach.
- Direct myotropic spasmolytic action. The drug is capable of directly affecting the smooth muscle of internal organs and blood vessels, causing relaxation regardless of the state of cholinergic innervation.
Pharmacological effects
Due to the combination of receptor and myotropic mechanisms, platyphylline effectively relieves spasms of smooth-muscle organs.
An important systemic effect distinguishing it from many other anticholinergics is its effect on the vascular bed. The drug causes vasodilation, resulting in a slight decrease in blood pressure (BP).
Indications for use
In clinical practice, the drug is used as a salt — platyphylline hydrotartrate. Main indications include:
- Spasms of abdominal smooth-muscle organs (including relief of renal colic).
- Peptic ulcer disease of the stomach and duodenum (as a spasmolytic and antisecretory agent reducing hydrochloric acid production).
- Cerebral vascular spasms.
- Peripheral vascular spasms.
Dosage forms and regimen
The drug is available in a wide range of dosage forms for enteral and parenteral administration:
- Powder;
- Tablets 0.005 g;
- Oral solution (drops) 0.5% — 15 ml;
- Solution in ampoules 0.2% — 1 ml;
- Suppositories 0.005 g.
Administration guidelines:
- Oral: prescribed strictly before meals at 0.003–0.005 g 2–3 times a day. As drops — 10–15 drops of a 0.5% solution 2–3 times a day.
- Parenteral: subcutaneously (s.c.), administer 1–2 ml of a 0.2% solution.
Dosage limitations for oral administration: Maximum single dose (MSD) is 0.01 g; Maximum daily dose (MDD) is 0.03 g.
Briefly: answers to topical questions
What side effects does platyphylline cause?
Platyphylline is an M-cholinergic blocker, and therefore exhibits the effects characteristic of this group:
- mydriasis;
- increased intraocular pressure;
- cycloplegia (paralysis of accommodation);
- dryness of mucous membranes and skin;
- tachycardia;
- relaxation of smooth muscle.
Additionally, platyphylline crosses the blood-brain barrier because it is a tertiary amine.
What are the contraindications to the use of platyphylline?
Platyphylline belongs to M-cholinergic blockers. Glaucoma is listed as a contraindication for M-cholinergic blockers.
This is due to the fact that M-cholinergic blockers cause mydriasis and relaxation of the ciliary muscle, which can impair the outflow of aqueous humor and lead to an increase in intraocular pressure.
In what types of colic is the use of platyphylline indicated?
Platyphylline is indicated for spasms of the smooth muscle organs of the abdominal cavity, including renal colic.
Sources also mention the use of platyphylline for hepatic/renal colic and during an attack of biliary colic as a fast-acting antispasmodic; for biliary colic, it is administered subcutaneously.
What are the symptoms of platyphylline overdose and first aid measures?
The provided sources do not describe the symptoms of platyphylline overdose specifically or the first aid measures for such an overdose.
Platyphylline has a DUAL action: it acts as a weak Atropine (M-cholinergic blocker) + as Papaverine (myotropic antispasmodic, dilates blood vessels and lowers blood pressure).
Class and exam questions
How does the mechanism of action of platyphylline differ from atropine?
Unlike atropine, platyphylline has a dual action: its M-cholinergic blocking effect is less pronounced, but it additionally exerts a direct myotropic antispasmodic effect on smooth muscles and blood vessels.
Does platyphylline penetrate into the brain?
Yes. Chemically, it is a tertiary ammonium base, so it is well absorbed and easily crosses the blood-brain barrier (BBB).
How does platyphylline affect blood pressure?
Due to its direct myotropic relaxing effect on the vascular wall, the drug causes vasodilation and a moderate decrease in blood pressure.
Which group of antisecretory agents does platyphylline belong to?
It belongs to the group of non-selective M-cholinergic blockers that inhibit hydrochloric acid secretion by gastric parietal cells (along with atropine).
What else to study on this topic
- Comparative characteristics of non-selective M-cholinergic blockers (atropine, platyphylline, scopolamine)
- Classification of antisecretory agents (H2-receptor blockers, proton pump inhibitors, M-cholinergic blockers)
- The effect of chemical structure (tertiary vs. quaternary amines) on the pharmacokinetics of cholinergic blockers
- Pharmacology of renal colic management
- Rules for prescribing prescriptions for alkaloids and their salts
Master the entire topic in the «Pharmacology» course
This is a summary. The course covers everything tested in classes and exams.
- Complete methodical guide on the topic "Platyphylline" and 5,304 other pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 116 video lessons on the subject
Other topics in the «Drugs and Prescriptions» section
Free video lessons: pharmacologyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.