There are important differences between dihydropyridines and other classes of calcium channel blockers.

Avoid the combination of verapamil with a beta-blocker (including eye drops). The combination of diltiazem with beta-blockers should be used with caution.

Avoid verapamil and diltiazem in heart failure.

Amlodipine

• Tablets 5mg, 10mg (£0.66 = 5mg daily)

Indications

• Hypertension
• Angina

Dose

• Initially 5mg once daily; maximum 10mg once daily

Diltiazem hydrochloride (standard formulation)

• Modified-release tablets 60mg (£6.18 = 84 tablets)

Indication

• Mild to moderate hypertension
• Angina

Notes

1. Standard formulations containing 60mg diltiazem hydrochloride are licensed as generics and there is no requirement for brand name dispensing for clinical reasons. Although their means of formulation has called for the strict designation 'modified-release', their duration of action corresponds to that of tablets requiring administration more frequently
2. Different versions of modified-release preparations containing more than 60mg diltiazem hydrochloride may not have the same clinical effect. To avoid confusion between these different formulations of diltiazem, prescribers should specify the brand to be dispensed (see entry below).
3. The combination of diltiazem with beta-blockers should be used with caution.

Diltiazem hydrochloride modified-release

• Adizem-SR modified-release capsules 90mg, 120mg, 180mg (£9.45 = 120mg twice daily)
• Adizem-XL modified-release capsules 120mg, 180mg, 200mg, 240mg, 300mg (£9.14 = 300mg once daily)
• Zemtard XL modified-release capsules 120mg, 180mg, 240mg, 300mg (£6.70 = 300mg once daily)

Indications and dose

• Mild to moderate hypertension
  • Adizem-SR: 120mg twice daily, dose form not appropriate for initial dose titration
  • Adizem-XL: Initially 240mg once daily, increased if necessary to 300mg once daily. Elderly and those with impaired hepatic or renal function, initially 120mg once daily
  • Zemtard XL: Initially 180mg-300mg once daily, increased if necessary to 360mg once daily. Elderly and those with renal impairment, initially 120mg once daily, increased if necessary to 360mg once daily
• Angina
  • Adizem-SR: Initially 90mg twice daily; increased if necessary to 180mg twice daily, dose form not appropriate for initial dose titration in the elderly
  • Adizem-XL: Initially 240mg once daily, increased if necessary to 300mg once daily. Elderly and those with impaired hepatic or renal function, initially 120mg once daily
  • Zemtard XL: Initially 180mg-300mg once daily, increased if necessary to 480mg once daily. Elderly and those with renal impairment, initially 120mg once daily, increased if necessary to 480mg once daily

Notes

1. Prescribe by brand. Different versions of modified-release preparations containing more than 60mg diltiazem hydrochloride may not have the same clinical effect. Switching patients stabilised on one brand is not routinely recommended. To avoid confusion between these different formulations of diltiazem, prescribers should specify the brand to be dispensed
2. If diltiazem prescriptions have been written generically in the past, the prescriber should attempt to ascertain which brand the patient has been taking and amend the prescription accordingly. If the brand taken has constantly changed, the prescriber should choose a formulary brand and prepare to review the patient and titrate the dose as appropriate.
3. Standard formulations containing 60mg diltiazem hydrochloride are licensed as generics and there is no requirement for brand name dispensing for clinical reasons. Although their means of formulation has called for the strict designation 'modified-release', their duration of action corresponds to that of tablets requiring administration more frequently (see individual entry above)
4. The combination of diltiazem with beta-blockers should be used with caution.

Felodipine

• Modified-release tablets 2.5mg, 5mg, 10mg (£3.87 = 5mg daily)

Indication

• Hypertension
• Angina

Dose

• Hypertension, initially 5mg (elderly 2.5mg) daily in the morning; usual maintenance 5–10mg once daily; doses above 20mg daily rarely needed
• Angina, initially 5mg daily in the morning, increased if necessary to 10mg once daily

Lercanidipine

• Tablets 10mg, 20mg (£2.32 = 10mg daily)

Indication

• Hypertension

Dose

• Initially 10mg once daily; increased, if necessary, after at least 2 weeks to 20mg daily

Verapamil

• Tablets 40mg, 80mg, 120mg, 160mg (£8.64 = 120mg three times a day)
• Half Securon SR modified-release tablets 120mg (£7.71)
• Securon SR modified-release tablets 240mg (£5.55)

Indications

• Supraventricular arrhythmias
• Angina
• Hypertension
• Prophylaxis after myocardial infarction where beta-blockers not appropriate

Dose

• Supraventricular arrhythmias, 40–120mg 3 times daily
• Angina, 80–120mg 3 times daily
  • Modified-release: 240mg twice daily (may sometimes be reduced to once daily)
• Hypertension, 240–480mg daily in 2–3 divided doses
  • Modified-release: 240mg daily (new patients initially 120mg), increased if necessary to maximum 480mg daily (doses above 240mg daily as 2 divided doses)
• Prophylaxis after myocardial infarction where beta-blockers not appropriate (started at least 1 week after infarction)
  • Modified-release: 360mg daily in divided doses, given as 240mg in the morning and 120mg in the evening or 120mg 3 times daily

Notes

1. Please specify the brand when prescribing modified-release verapamil to ensure that the patient receives the same modified-release preparation. Where a patient already receives a modified-release verapamil preparation the existing brand should be prescribed.

Nifedipine (modified-release formulations)

• Modified-release capsules 10mg, 20mg, 30mg, 60mg
• Modified-release tablets 10mg, 20mg, 30mg, 60mg

Indications

• Angina prophylaxis
• Hypertension
• Hypertension in pregnancy (second line)

Notes

1. At the time of writing (July 2019) Adalat Retard formulations have been discontinued, and there are long term supply problems with Adalat LA. Other brands remain available including Coracten SR capsules and XL capsules; and Adipine MR tablets and XL tablets however intermittent supply problems with alternative brands have also been observed.
   1. It is advised that modified-release preparations of nifedipine should be prescribed by brand as different preparations may not have the same clinical effect; this may not be possible in the event of supply problems.
   2. When switching between brands closer monitoring of blood pressure may be required in the initial stages and patients reassured that they are receiving the same drug and dose but to report any adverse effects.
   3. Licensed indications and recommended dosing frequencies vary between products and should be checked when switching treatments.
   4. Local specialists have provided guidance on switching patients to an alternative calcium-channel blocker which can be found on the Medicines Optimisation Post Live
2. Pregnancy: May inhibit labour; manufacturer advises avoid before week 20, but risk to foetus should be balanced against risk of uncontrolled maternal hypertension

Nifedipine (short-acting formulation)

• Capsules 5mg, 10mg

Indications

• Raynaud's phenomenon

Dose

• Initially 5mg 3 times a day, adjusted according to response to 20mg 3 times a day

Notes

1. The short-acting nifedipine capsules are not to be prescribed for hypertension or angina; their use maybe associated with large variations in blood pressure and reflex tachycardia.
2. General measures, e.g. withdrawal of beta-blockers, stopping smoking, use of hand warmers, should be encouraged before introduction of drug therapy for Raynaud's phenomenon.
3. Local specialists have provided guidance on switching patients to an alternative calcium-channel blocker in the event of supply shortages which can be found on the Medicines Optimisation Post Live

Nimodipine

• Tablets 30mg
• Solution for infusion vials 10mg.50ml

Indications

• Nimodipine is included for the prevention and treatment of ischaemic neurological deficits following subarachnoid haemorrhage. The full course will be supplied by Secondary Care.