GDC is not a medicine. It is a supplier marking that appears after the ingredient name on certain South African generic packs — “Fluconazole 150 GDC”, “Theophylline 200 GDC”. What the tablets treat depends entirely on the word in front of the GDC.
What is Gdc?
GDC on a medicine pack identifies the supplier, not the medicine. The South African Medicine Price Registry lists three products carrying it, and they treat entirely unrelated conditions:
| Product | Schedule | Active ingredient | Treats |
|---|---|---|---|
| Fluconazole 150 GDC | S2 | Fluconazole 150 mg | Fungal infection — usually thrush |
| Theophylline 200 GDC | S2 | Theophylline 200 mg | Asthma and COPD |
| Theophylline 300 GDC | S2 | Theophylline 300 mg | Asthma and COPD |
An antifungal and a lung medicine share nothing but the marking on the box.
Why generic packs are named this way. Once a medicine’s patent expires, other companies may supply it. Regulators require the generic name — the actual active ingredient — to be the prominent name, and the supplier adds a short identifier to distinguish their version. So “Fluconazole 150 GDC” reads as [ingredient] [strength] [supplier]. The same convention produces “Metformin 500 Biotech”, “Ibuprofen 200 Clicks” and “Aspen Trazodone”.
The useful information is always the first word. Fluconazole is fluconazole whoever supplies it.
Generic medicines are held to the same standards as originals. SAHPRA requires the same active ingredient at the same strength, and proven bioequivalence — the same amount reaching the bloodstream at the same rate. They cost less because the supplier did not fund the original research.
What is Gdc commonly used for?
There is no single answer, because GDC is not one medicine. Briefly, the two ingredients it appears on:
Fluconazole 150 mg is an antifungal, most often a single capsule for vaginal thrush. It is also used for oral thrush, fungal skin infections, and — at different doses and durations — more serious fungal infections, including in people with HIV. It is Schedule 2, available from a pharmacist.
Theophylline is a bronchodilator for asthma and COPD, relaxing the airways. It is an old medicine, largely superseded by inhalers, and is now used mainly as an add-on where inhaled treatment is not enough. It has a narrow safety margin — the effective dose sits close to the toxic one — so blood levels are sometimes monitored, and it interacts with a long list of other medicines including some antibiotics.
How to find out what you have:
Read the box. The active ingredient and strength are printed on it, immediately before the supplier name.
Read the dispensing label, which carries the medicine name and directions.
Check the leaflet inside, which names the ingredient and what it treats.
Ask the pharmacist. Free, immediate, and precisely what they are for.
Phone the pharmacy that dispensed it if the packaging is gone.
The commonest reason people search a supplier name is generic substitution — this month’s box looks nothing like last month’s. That is normal, legal and usually cheaper. Ask the pharmacist to confirm it is the same medicine if it worries you.
Do not take a tablet you cannot identify.
How Gdc fits into this medicine category
GDC-labelled products span unrelated categories:
| Category | GDC product | Related guides |
|---|---|---|
| Antifungals | Fluconazole 150 | Metronidazole, Azrotrin |
| Respiratory | Theophylline 200, 300 | Asthma and COPD guides |
Fluconazole is an antifungal, not an antibiotic, which is worth stating since this page sits in the antibiotics category. Antibiotics kill bacteria; antifungals kill fungi. An antibiotic will not treat thrush — and in fact antibiotics commonly cause thrush, by clearing the bacteria that normally keep yeast in check.
A supplier name is not a clinical category. Grouping medicines by who supplies them tells you nothing about what they do.
See the antibiotics and antimicrobials hub.
What to check before using Gdc
Identify the active ingredient first. Then, briefly:
If it is fluconazole, tell your pharmacist or doctor if you:
- Take warfarin, statins, phenytoin, rifampicin, ciclosporin, or medicines affecting heart rhythm. Fluconazole interacts with a great many medicines.
- Have liver disease or kidney disease.
- Are pregnant or planning pregnancy. Fluconazole is avoided in pregnancy, particularly at higher or repeated doses.
- Have a heart rhythm problem or a long QT interval.
- Have recurrent thrush — more than about four episodes a year warrants assessment rather than repeated single doses.
If it is theophylline, tell your doctor if you:
- Take antibiotics — particularly ciprofloxacin, erythromycin or clarithromycin, which raise theophylline to toxic levels. This is a genuinely dangerous and common interaction.
- Smoke or have recently stopped. Smoking changes how quickly theophylline is cleared, and stopping can push levels up sharply.
- Have heart disease, liver disease, thyroid problems, epilepsy or stomach ulcers.
- Have a fever or viral illness, which slows clearance.
- Take cimetidine, allopurinol, anti-epileptics or the contraceptive pill.
Never adjust a theophylline dose yourself, and take the same brand consistently where possible — different formulations release at different rates.
Possible cautions and when to ask a pharmacist or doctor
Fluconazole is generally well tolerated. Common effects are nausea, headache, abdominal pain and diarrhoea. Seek advice for a rash — it is associated with rare severe skin reactions — or for yellowing of the skin or eyes.
Theophylline has a narrow margin, and its side effects are the early signs of toxicity. Seek prompt advice for nausea, vomiting, headache, tremor, restlessness, insomnia or palpitations, particularly if they are new. Get emergency help for a fast or irregular heartbeat, severe vomiting, agitation, confusion or a seizure — these indicate toxicity, which can be life-threatening.
Get emergency help, whatever the medicine, for:
- Swelling of the face, lips or tongue, or difficulty breathing.
- A widespread rash with blistering, peeling, mouth sores or fever.
- Chest pain, fainting, or a seizure.
- Severe abdominal pain, vomiting blood, or black tarry stools.
- Any suspected overdose, even if the person seems well. Take the packaging.
Ask a pharmacist if you cannot identify a medicine, or if your generic has changed and you are unsure. See a doctor if you have taken something unidentified and feel unwell, if thrush keeps returning, if asthma or breathlessness is worsening, or if you take several medicines and would like them reviewed together.
Related medicine guides
Frequently asked questions
What is GDC used for? Nothing on its own — GDC is a supplier marking on generic packs, not a medicine. The word in front of it names the actual ingredient.
What medicines carry the GDC name? On the South African price registry: Fluconazole 150 GDC, an antifungal usually taken as a single capsule for thrush, and Theophylline 200 and 300 GDC, used for asthma and COPD.
Is fluconazole an antibiotic? No, it is an antifungal. Antibiotics kill bacteria and do not treat thrush — in fact they commonly cause it.
How do I find out what my tablets treat? Read the active ingredient on the box, check the leaflet, or ask the pharmacist. If the packaging is gone, phone the pharmacy that dispensed it.
My pack looks different from last month. Why? Usually generic substitution — the same medicine from a different supplier. Ask the pharmacist to confirm.
Are generics as good as the original? Yes. SAHPRA requires the same active ingredient at the same strength and proven bioequivalence.
Why does theophylline need so much care? It has a narrow safety margin, and several common antibiotics — ciprofloxacin, erythromycin, clarithromycin — push it into the toxic range. Tell any prescriber that you take it.