Solid dosage forms: tablets and powders
In prescription practice, solid forms occur as powders (pulvis) and tablets (tabulettae).
If it is necessary to prescribe a ready-made dosage form indicating the exact number of units, its name is put in the accusative plural case. For example, a prescription for methylandrostenediol tablets will look like this: Recipe: Tabulettas Methylandrostendioli 0,025 numero 30. If the tablets are coated, the participle obductas is added to the name of the form (e.g., for oleandomycin phosphate tablets).
Powders are divided into simple and complex, weighed and non-weighed. In a complex non-weighed powder (e.g., with streptocide, norsulfazole, benzylpenicillin-sodium, and ephedrine), ingredients are listed sequentially. To indicate equal parts, the word ana (abbreviated as aa — in equal parts) is used. The prescription ends with instructions for the pharmacist: Misce, fiat pulvis (Mix, let a powder be made). If the powder is weighed (as in the prescription with codeine, acetylsalicylic acid, rutin, and diphenhydramine), it is necessary to add the phrase: Da tales doses numero... (Dispense such doses in the number of...).
Liquid dosage forms: solutions, drops, and mixtures
Liquid forms include solutions (solutio), complex drops, and mixtures.
An important rule: specifying the concentration (in percent) and volume (in milliliters) automatically implies the solution form, even if the word "solution" is not explicitly written. The prescription begins with the word Solutionis in the genitive case. Examples from the workshop: Solutionis Hydrargyri oxycyanidi 0,01 % — 50 ml or Solutionis Thiamini bromidi 3 % — 1 ml. If the solution is intended for injection and produced in ampoules, the phrase in ampullis is added at the end of the prescription.
When formulating complex mixtures and drops, the preposition ad (to) is often used. It means that the solvent must be added in the amount necessary to reach the total volume. For example, in a mixture with morphine and apomorphine, distilled water is prescribed ad 200 ml (up to 200 ml), and in drops with menthol and phenyl salicylate, liquid paraffin — ad 10 ml.
Semi-solid dosage forms: ointments and liniments
Semi-solid forms include ointments (unguentum) and their more fluid analogues — liniments (linimentum).
When prescribing a complex ointment, all active substances and the ointment base are listed. For example, in the prescription for an ointment with silver nitrate (0.25) and vinylin (1.0), petrolatum (Vaselini) with a mass of 30.0 grams is prescribed as the base. After listing all components, the standard instruction is given: Misce, fiat unguentum (Mix, let an ointment be made).
In liniments, liquid components are often taken in equal volumes. An example is a complex liniment consisting of chloroform, sunflower oil (Olei Helianthi), and methyl salicylate. Since 15 ml of each substance is required, ana is written before the last figure. Such a prescription ends with the phrase Misce, fiat linimentum.
Prescription abbreviations and standard phrases
Medical Latin involves the active use of established abbreviations and phrases. The main ones encountered in prescriptions:
- M.f. pulvis / unguentum — Misce, fiat... (Mix, let a powder / ointment be made). Used when the pharmacist needs to prepare the form from the listed ingredients.
- D.t.d. N. — Da tales doses numero... (Dispense such doses in the number of...). Indicates the number of doses to be dispensed to the patient (e.g., in ampoules or as divided powders).
- M.D.S. — Misce. Da. Signa. (Mix. Dispense. Label). A complex command for preparation, dispensing, and writing instructions on the label.
- IU — International Units. Used for dosing antibiotics such as phenoxymethylpenicillin (100,000 IU) or benzylpenicillin (25,000 IU).
Briefly: answers to topical questions
In which case should the name of the medicinal substance or plant stand after the heading Recipe?
The name of the medicinal substance or plant after the heading Recipe must be in the genitive singular or plural case (Genitivus singularis or pluralis), with the exception of prescriptions for ready-made dosage forms beginning with the accusative case.
To avoid confusing prepositions: "ad" (to) is the final boundary (add TO the required volume), and "ana" (in equal parts) is the equality of all components listed before it.
Class and exam questions
In which case are finished dosage forms written out when their quantity is indicated?
The name of the form (e.g., tablets) is written out in the accusative case plural: Tabulettas.
How is the abbreviation D.t.d. N. translated and when is it used?
It stands for "Da tales doses numero" (Dispense such doses in the number of) and is used when it is necessary to multiply the prescribed single dose of a drug by a given number of portions.
How to understand that a solution is being prescribed if this word is not in the task?
If the drug has a percentage concentration (%) and volume in milliliters (ml) specified, this automatically means that the dosage form is a solution (Solutio).
What else to study on this topic
- Rules for prescribing antibiotics in International Units (IU)
- Formatting prescriptions for solutions in ampoules (in ampullis)
- Use of the prepositions ana and ad in complex multi-component prescriptions
- Specifics of prescribing complex mixtures with diluted acids (diluti)
- Grammatical agreement of modifiers (e.g., isotonicae, obductas) with the dosage form
Master the entire topic in the "Latin Language" course
This is a summary. The course covers everything tested in classes and exams.
- Complete methodological guide on the "Prescription Writing Workshop" topic and 2,323 more subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 107 video lessons on the subject
Other topics in the "Salt Names" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.