Diltiazem 360 mg capsules being discontinued — what patients need to know

Drug discontinuations sit in an awkward category of health news. They are not dramatic. There is rarely a safety crisis behind them — manufacturing issues, commercial decisions, supply chain mathematics. But for a person managing a chronic cardiovascular condition on a medication that has been stable for years, finding out their product is no longer available can feel destabilising. And in the worst-case scenario, where the information does not reach them in time, they can find themselves without supply before they have had a chance to plan.

Both Australian brands of diltiazem 360 mg controlled-release capsules are being discontinued. Cardizem CD 360 mg (Sanofi-Aventis Australia) has been unavailable since June 2026. Vasocardol CD 360 mg will no longer be supplied in Australia from 1 November 2026, with reduced availability expected in the weeks before that date. The reason given is manufacturing issues.

Diltiazem at this dose is used primarily for hypertension and angina. It is a calcium-channel blocker, and the controlled-release formulation is designed for once-daily dosing — a practical advantage for people managing multiple medications for chronic conditions.

What is in place to manage the supply gap

The TGA has moved quickly here. A Serious Scarcity Substitution Instrument (SSSI, F2026L01305) came into effect on 1 October 2026 and runs to 1 October 2027. Under this instrument, a pharmacist can dispense diltiazem 180 mg controlled-release capsules in place of the 360 mg formulation without requiring a new prescription from the prescribing doctor. The logic is straightforward: two 180 mg doses provide the same total daily dose in the same controlled-release format.

This is how Australia handles medicine discontinuations and shortages when a workable substitution exists. The SSSI removes the administrative barrier of requiring a new prescription for each patient, which would otherwise create a bottleneck in general practice at exactly the moment when patients are anxious and pharmacies are fielding a surge of questions.

The TGA’s guidance notes that pharmacists should consider clinical factors before substituting — so if your pharmacist has questions, that is appropriate clinical caution, not obstructiveness.

Both-and: manageable, but not invisible

For most people on diltiazem 360 mg, the transition to two 180 mg capsules will be seamless. The total dose is the same, the controlled-release mechanism is the same, and the substitution pathway removes the prescription burden. This is a well-managed discontinuation response.

Where it becomes worth paying attention: controlled-release formulations can have subtle differences in their release profiles depending on the specific product. For someone whose blood pressure has been tightly managed, or who has had recent dose adjustments, a formulation change — even a technically equivalent one — is a moment to monitor more carefully. The same total dose does not always translate to exactly the same absorption curve, and blood pressure or angina control can occasionally show variation in the first few weeks.

The other practical consideration: going from one capsule a day to two is a small change in pill burden, but for people already managing complex medication regimens, it is worth flagging to the prescribing doctor to update the medication list. Accuracy on a medication list matters at hospital admissions and care transitions.

2 cents

If you or someone you support is on Cardizem CD 360 mg or Vasocardol CD 360 mg, two things are worth doing before the end of October.

First, ask your pharmacist about the SSSI — they can confirm whether diltiazem 180 mg is in stock and explain how the substitution works. The consultation at the pharmacy is the right first step.

Second, consider booking a GP review before the November cutoff — particularly if blood pressure or chest pain management has been variable recently, or if the person has a complex medication history. This is not an emergency, and not everyone will need a dedicated appointment. But for anyone whose cardiovascular management has been anything other than stable and straightforward, having a clinician confirm the transition plan is worthwhile.

The TGA substitution instrument is a reasonable safety net. It is designed exactly for this kind of situation. Using it alongside a brief GP conversation — rather than instead of one — is the sensible path.

Verdict: yes — directly actionable for anyone on diltiazem 360 mg, and worth knowing about before November 2026 supply dries up.

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Sources cited

1. In Practice: Hypertension drug discontinued — RACGP newsGP
2. About discontinuation of diltiazem 360 mg controlled-release capsules — TGA
3. Serious Scarcity Substitution Instrument F2026L01305 — Federal Register of Legislation