Drugs List

Therapeutic Indications

Uses

Treatment of angina pectoris.
Treatment of mild to moderate hypertension.
Prinzmetal's angina.

Administration

For oral administration. Dose to be swallowed whole with water, not crushed or chewed. Dose may be taken with or without food.

In some cases a tablet or capsule may pass through the body unchanged.

Contraindications

Second or third degree AV block (except in patients with ventricular pacemaker)
Severe bradycardia (pulse rate at rest < 40 beats per minute)
Hypotension (systolic pressure less than 90mmHg)
Sick sinus syndrome in the absence of a ventricular pacemaker (Non-paced sinus node dysfunction)
Decompensated cardiac failure
Myocardial infarction complicated by significant bradycardia, systolic hypotension, left ventricular dysfunction or congestive cardiac failure
Atrial fibrillation/flutter and simultaneous presence of a Wolff-Parkinson-White syndrome (increased risk of triggering a ventricular tachycardia)
Lown-Ganong-Levine syndrome
Left ventricular failure with stasis or with pulmonary congestion
Children under 18 years (see Dosage; Children)
Hereditary fructose intolerance
Pregnancy (see Pregnancy section)
Cardiogenic Shock
Porphyria (see Use in Porphyria section)

Precautions and Warnings

Different versions of modified-release preparations may not have the same clinical effect. To avoid confusion between these different formulations of diltiazem, prescribers should specify the brand to be dispensed.

Diltiazem prolongs AV node refractory periods without significantly prolonging sinus node recovery time, except in patients with sick sinus syndrome. This effect may result in abnormally slow heart rates (particularly in patients with sick sinus syndrome) or second or third degree AV block. Use with caution and monitor patients with:
First degree AV block
Prolonged PR conduction interval (risk of exacerbation and rarely, complete block)
Reduced left ventricular function/cardiac failure
Mild bradycardia (risk of exacerbation)

Not all brands are licensed for use in Prinzmetal's angina.

There is some evidence that sudden withdrawal of calcium channel blockers may be associated with exacerbation of angina.

Calcium channel blockers do not reduce the risk of myocardial infarction in unstable angina. The use of diltiazem should be reversed for patients resistant to treatment with beta-blockers. However, because of the risk of bradycardia diltiazem should be used with caution in association with beta-blockers. Avoid concurrent use of beta blockers with diltiazem in patients with pre-existing conduction defects.

Inform anaesthetist that patient is taking a calcium channel antagonist . During anaesthesia, depression of cardiac contractility, conductivity and automaticity, and vascular dilatation may be exacerbated by calcium channel blockers.

Hepatic impairment - ( see Dosage; Patients with Hepatic Impairment ). Abnormalities of liver function may occur during therapy. Occasional reports of abnormal liver function have been received, these reactions have been reversible upon discontinuation of therapy.

Renal impairment - ( see Dosage; Patients with Renal Impairment )

Elderly - may require dose reduction ( see Dosage; Elderly ).

In women of child-bearing age, exclude pregnancy before starting treatment.
Advise women to use adequate contraception during treatment with diltiazem.

Breastfeeding ( see Lactation section )

Use with caution in patients with myasthenia gravis - there has been reports of calcium channel blockers exacerbating muscle weakness.

Diabetes mellitus - diltiazem hydrochloride may affect the hypoglycaemic response and adjustment of diabetic treatment may be necessary.

Treatment with diltiazem may be associated with mood changes, including depression. Early recognition of the relevant symptoms is important, especially in predisposed patients. In such cases, drug discontinuation should be considered.

Dizziness and malaise are common side effects of diltiazem therapy. Do not drive or operate machinery if affected.

The release profile of some brands may be affected by alcohol, those which are should not be taken at the same time as consuming alcohol.

As with all modified-release preparations, the capsules should be swallowed whole and not sucked or chewed.
In some cases a tablet or capsule may pass through the gastrointestinal tract unchanged.
Use with caution in patients at risk of developing an intestinal obstruction as diltiazem has an inhibitory effect on intestinal motility.

Some brands contain lactose. Therefore, patients with galactosaemia, glucose-galactose malabsorption syndrome or lactose intolerance should avoid those brands.

Some brands contain sucrose. Therefore, patients with hereditary fructose intolerance and glucose-galactose malabsorption should avoid those brands.

The use of diltiazem may induce bronchospasm, including asthma aggravation, especially in patients with pre-existing hyper-reactivity. Monitor patients for signs and symptoms of respiratory impairment during treatment.

Acute renal failure secondary to decreased renal perfusion has been reported in patients with reduced left ventricular function, severe bradycardia or severe hypotension.

Use in Porphyria

Diltiazem is contraindicated in porphyria.
Diltiazem is classified as probably porphyrinogenic as it is a substrate for several CYPs including CYP 3A4 and it is a potent CYP 3A4 inhibitor. (NAPOS the Drug Database for Acute Porphyria, 2004).

Pregnancy and Lactation

Pregnancy

Diltiazem is contraindicated during pregnancy.

Animal studies in rats, rabbits and mice revealed an increase in embryonic and foetal mortality. Skeletal abnormalities and digital defects were reported. Schaefer comments, that for antiarrhythmic therapy, although animal data indicate teratogenic developmental disturbances of distal phalanges, similar effects have not been seen in human pregnancies and in the class IV antiarrhythmic drugs diltiazem is acceptable.

There is little experience with the use of diltiazem in the first trimester of pregnancy. Early embryonic differentiation may be disturbed with results including digital defects. Diltiazem may suppress the contractility of the uterus, however comprehensive evidence that this will prolong the partus in full-term pregnancy is lacking. A risk of hypoxia in the foetus may arise in the event of hypotension in the mother and reduced perfusion of the uterus. One study reported there may be a association with cardiovascular defects in newborns and the use of diltiazem in the first trimester of pregnancy, but maternal disease, concurrent drug use and chance can not be ruled out. Information from CKS notes that there is low risk to the foetus.

Schaefer (2007) comments that in the first trimester, calcium antagonists are considered to be second line therapy and suggests that following exposure during the first trimester a detailed ultrasound examination should be undertaken, but neither invasive diagnostic procedures or termination of pregnancy are required. It is advised that pregnancy is excluded prior to the initiation of treatment and that women of child bearing potential use effective contraception throughout treatment.

The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Licensed in pregnancy? - No

Recommended for use in pregnancy? - No

Animal data - reports increased mortality in rats, rabbits and mice and reports of skeletal defects.

Effects on foetus - Digital defects and risk of hypoxia in the foetus.

Other information - Exclude pregnancy prior to the initiation of treatment. Women of child bearing potential should use effective contraception throughout treatment.

Lactation

Diltiazem should be used with caution in nursing mothers.

Diltiazem is excreted in human breast milk with approximately equal concentration in maternal serum and the breast milk. The quantities ingested by the infant are likely to be small and Hale (2010) considers the quantity unlikely to be problematic. Use of diltiazem should be avoided unless there is no safer alternative. The UKMi Drugs in lactation states that there is limited information to relating to breastfeeding available to allow classification as a safe drug and as such this drug can be administered to breastfeeding mothers only where the mother and infant can be monitored. Schaefer (2007) considers diltiazem to be one of the calcium channel blockers of choice for hypertension while breastfeeding. Possible effects on the infant include hypotension and bradycardia.

Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1Drug excreted in breast milk? - Yes

Considered suitable or recommended by manufacturer? - No

UK Drugs in Lactation Advisory Service Classification - may be administered only when mother and infant can be monitored

Drug substance licensed in infants? - No.

Side Effects

Lower limb oedema
Headache
Dizziness
Asthenia
Atrioventricular block
Flushing
Nausea
Bradycardia
Rash
Erythema
Urticaria
Desquamative erythema
Angina
Arrhythmias
Sino-atrial block
Congestive cardiac failure
Syncope
Hypotension
Palpitations
Amnesia
Depression
Gait abnormality
Hallucinations
Insomnia
Nervousness
Paraesthesia
Personality change
Drowsiness
Tinnitus
Tremor
Anorexia
Constipation
Diarrhoea
Dyspepsia
Increase in alkaline phosphatase
Increase in serum ALT/AST
Increase in lactate dehydrogenase
Vomiting
Weight gain
Gingivitis
Gingival hyperplasia
Petechiae
Pruritus
Photosensitivity
Allergic skin reactions
Erythema multiforme
Exfoliative dermatitis
Vasculitis
Angioneurotic oedema
Lymphadenopathy
Eosinophilia
Fever
Amblyopia
Creatine kinase increased
Dyspnoea
Epistaxis
Eye irritation
Hyperglycaemia
Dry mouth
Nasal congestion
Nocturia
Osteoarticular pain
Polyuria
Sexual dysfunction
Malaise
Gynaecomastia
Extrapyramidal effects
Hepatitis
Fatigue
Gastro-intestinal symptoms
Somnolence
Gastric pain
Orthostatic hypotension
Toxic epidermal necrolysis
Stevens-Johnson syndrome
Impotence
Acute generalised exanthematous pustulosis
Thrombocytopenia
Taste disturbances
Leukocytoclastic vasculitis
Bundle branch block
Hyperpigmentation
Mood changes
Muscle pain
Muscle weakness
Parkinsonism
Sweating
Oedema
Abdominal pain
Lichenoid keratosis
Bronchospasm
Aggravation of existing asthma
Acute renal failure

Presentation

12 hour modified release tablets containing 90mg of diltiazem hydrochloride.
12 hour modified release tablets containing 120mg of diltiazem hydrochloride.
12 hour modified release capsules containing 60mg of diltiazem hydrochloride.
12 hour modified release capsules containing 90mg of diltiazem hydrochloride.
12 hour modified release capsules containing 120mg of diltiazem hydrochloride.
12 hour modified release capsules containing 180mg of diltiazem hydrochloride.

Drugs List

Therapeutic Indications

Uses

Treatment of angina pectoris.
Treatment of mild to moderate hypertension.
Prinzmetal's angina.

Dosage

Care titration should be considered where appropriate, as individual response may vary. Dosage requirements can differ significantly between individuals.

Different modified release preparations may not have the same clinical effect. Prescribers should specify the brand to be supplied.

Different modified release preparations may have different recommended initial and maximum doses. Consult specific brand literature.

Adults

Elderly

Children

Patients with Renal Impairment

Patients with Hepatic Impairment

Administration

For oral administration. Dose to be swallowed whole with water, not crushed or chewed. Dose may be taken with or without food.

In some cases a tablet or capsule may pass through the body unchanged.

Contraindications

Second or third degree AV block (except in patients with ventricular pacemaker)
Severe bradycardia (pulse rate at rest < 40 beats per minute)
Hypotension (systolic pressure less than 90mmHg)
Sick sinus syndrome in the absence of a ventricular pacemaker (Non-paced sinus node dysfunction)
Decompensated cardiac failure
Myocardial infarction complicated by significant bradycardia, systolic hypotension, left ventricular dysfunction or congestive cardiac failure
Atrial fibrillation/flutter and simultaneous presence of a Wolff-Parkinson-White syndrome (increased risk of triggering a ventricular tachycardia)
Lown-Ganong-Levine syndrome
Left ventricular failure with stasis or with pulmonary congestion
Children under 18 years (see Dosage; Children)
Hereditary fructose intolerance
Pregnancy (see Pregnancy section)
Cardiogenic Shock
Porphyria (see Use in Porphyria section)

Precautions and Warnings

Different versions of modified-release preparations may not have the same clinical effect. To avoid confusion between these different formulations of diltiazem, prescribers should specify the brand to be dispensed.

Diltiazem prolongs AV node refractory periods without significantly prolonging sinus node recovery time, except in patients with sick sinus syndrome. This effect may result in abnormally slow heart rates (particularly in patients with sick sinus syndrome) or second or third degree AV block. Use with caution and monitor patients with:
First degree AV block
Prolonged PR conduction interval (risk of exacerbation and rarely, complete block)
Reduced left ventricular function/cardiac failure
Mild bradycardia (risk of exacerbation)

Not all brands are licensed for use in Prinzmetal's angina.

There is some evidence that sudden withdrawal of calcium channel blockers may be associated with exacerbation of angina.

Calcium channel blockers do not reduce the risk of myocardial infarction in unstable angina. The use of diltiazem should be reversed for patients resistant to treatment with beta-blockers. However, because of the risk of bradycardia diltiazem should be used with caution in association with beta-blockers. Avoid concurrent use of beta blockers with diltiazem in patients with pre-existing conduction defects.

Inform anaesthetist that patient is taking a calcium channel antagonist . During anaesthesia, depression of cardiac contractility, conductivity and automaticity, and vascular dilatation may be exacerbated by calcium channel blockers.

Hepatic impairment - ( see Dosage; Patients with Hepatic Impairment ). Abnormalities of liver function may occur during therapy. Occasional reports of abnormal liver function have been received, these reactions have been reversible upon discontinuation of therapy.

Renal impairment - ( see Dosage; Patients with Renal Impairment )

Elderly - may require dose reduction ( see Dosage; Elderly ).

In women of child-bearing age, exclude pregnancy before starting treatment.
Advise women to use adequate contraception during treatment with diltiazem.

Breastfeeding ( see Lactation section )

Use with caution in patients with myasthenia gravis - there has been reports of calcium channel blockers exacerbating muscle weakness.

Diabetes mellitus - diltiazem hydrochloride may affect the hypoglycaemic response and adjustment of diabetic treatment may be necessary.

Treatment with diltiazem may be associated with mood changes, including depression. Early recognition of the relevant symptoms is important, especially in predisposed patients. In such cases, drug discontinuation should be considered.

Dizziness and malaise are common side effects of diltiazem therapy. Do not drive or operate machinery if affected.

The release profile of some brands may be affected by alcohol, those which are should not be taken at the same time as consuming alcohol.

As with all modified-release preparations, the capsules should be swallowed whole and not sucked or chewed.
In some cases a tablet or capsule may pass through the gastrointestinal tract unchanged.
Use with caution in patients at risk of developing an intestinal obstruction as diltiazem has an inhibitory effect on intestinal motility.

Some brands contain lactose. Therefore, patients with galactosaemia, glucose-galactose malabsorption syndrome or lactose intolerance should avoid those brands.

Some brands contain sucrose. Therefore, patients with hereditary fructose intolerance and glucose-galactose malabsorption should avoid those brands.

The use of diltiazem may induce bronchospasm, including asthma aggravation, especially in patients with pre-existing hyper-reactivity. Monitor patients for signs and symptoms of respiratory impairment during treatment.

Acute renal failure secondary to decreased renal perfusion has been reported in patients with reduced left ventricular function, severe bradycardia or severe hypotension.

Use in Porphyria

Diltiazem is contraindicated in porphyria.
Diltiazem is classified as probably porphyrinogenic as it is a substrate for several CYPs including CYP 3A4 and it is a potent CYP 3A4 inhibitor. (NAPOS the Drug Database for Acute Porphyria, 2004).

Pregnancy and Lactation

Pregnancy

Diltiazem is contraindicated during pregnancy.

Animal studies in rats, rabbits and mice revealed an increase in embryonic and foetal mortality. Skeletal abnormalities and digital defects were reported. Schaefer comments, that for antiarrhythmic therapy, although animal data indicate teratogenic developmental disturbances of distal phalanges, similar effects have not been seen in human pregnancies and in the class IV antiarrhythmic drugs diltiazem is acceptable.

There is little experience with the use of diltiazem in the first trimester of pregnancy. Early embryonic differentiation may be disturbed with results including digital defects. Diltiazem may suppress the contractility of the uterus, however comprehensive evidence that this will prolong the partus in full-term pregnancy is lacking. A risk of hypoxia in the foetus may arise in the event of hypotension in the mother and reduced perfusion of the uterus. One study reported there may be a association with cardiovascular defects in newborns and the use of diltiazem in the first trimester of pregnancy, but maternal disease, concurrent drug use and chance can not be ruled out. Information from CKS notes that there is low risk to the foetus.

Schaefer (2007) comments that in the first trimester, calcium antagonists are considered to be second line therapy and suggests that following exposure during the first trimester a detailed ultrasound examination should be undertaken, but neither invasive diagnostic procedures or termination of pregnancy are required. It is advised that pregnancy is excluded prior to the initiation of treatment and that women of child bearing potential use effective contraception throughout treatment.

The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Licensed in pregnancy? - No

Recommended for use in pregnancy? - No

Animal data - reports increased mortality in rats, rabbits and mice and reports of skeletal defects.

Effects on foetus - Digital defects and risk of hypoxia in the foetus.

Other information - Exclude pregnancy prior to the initiation of treatment. Women of child bearing potential should use effective contraception throughout treatment.

Lactation

Diltiazem should be used with caution in nursing mothers.

Diltiazem is excreted in human breast milk with approximately equal concentration in maternal serum and the breast milk. The quantities ingested by the infant are likely to be small and Hale (2010) considers the quantity unlikely to be problematic. Use of diltiazem should be avoided unless there is no safer alternative. The UKMi Drugs in lactation states that there is limited information to relating to breastfeeding available to allow classification as a safe drug and as such this drug can be administered to breastfeeding mothers only where the mother and infant can be monitored. Schaefer (2007) considers diltiazem to be one of the calcium channel blockers of choice for hypertension while breastfeeding. Possible effects on the infant include hypotension and bradycardia.

Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1Drug excreted in breast milk? - Yes

Considered suitable or recommended by manufacturer? - No

UK Drugs in Lactation Advisory Service Classification - may be administered only when mother and infant can be monitored

Drug substance licensed in infants? - No.

Effects on Ability to Drive and Operate Machinery

Dizziness and malaise are common side effects of diltiazem therapy. Do not drive or operate machinery if affected.

Counselling

Advise patients that the tablets or capsules should be swallowed whole, not sucked or chewed.

In some cases a tablet or capsule membrane may pass through the gastrointestinal tract unchanged.

Advise patients not to drive if they are affected by side effects such as dizziness or malaise

Advise women of child bearing age to use adequate contraception during treatment.

Inform patient of the possible adverse effects on their mood.

Advise patient to report any new or worsening respiratory symptoms.

Side Effects

Lower limb oedema
Headache
Dizziness
Asthenia
Atrioventricular block
Flushing
Nausea
Bradycardia
Rash
Erythema
Urticaria
Desquamative erythema
Angina
Arrhythmias
Sino-atrial block
Congestive cardiac failure
Syncope
Hypotension
Palpitations
Amnesia
Depression
Gait abnormality
Hallucinations
Insomnia
Nervousness
Paraesthesia
Personality change
Drowsiness
Tinnitus
Tremor
Anorexia
Constipation
Diarrhoea
Dyspepsia
Increase in alkaline phosphatase
Increase in serum ALT/AST
Increase in lactate dehydrogenase
Vomiting
Weight gain
Gingivitis
Gingival hyperplasia
Petechiae
Pruritus
Photosensitivity
Allergic skin reactions
Erythema multiforme
Exfoliative dermatitis
Vasculitis
Angioneurotic oedema
Lymphadenopathy
Eosinophilia
Fever
Amblyopia
Creatine kinase increased
Dyspnoea
Epistaxis
Eye irritation
Hyperglycaemia
Dry mouth
Nasal congestion
Nocturia
Osteoarticular pain
Polyuria
Sexual dysfunction
Malaise
Gynaecomastia
Extrapyramidal effects
Hepatitis
Fatigue
Gastro-intestinal symptoms
Somnolence
Gastric pain
Orthostatic hypotension
Toxic epidermal necrolysis
Stevens-Johnson syndrome
Impotence
Acute generalised exanthematous pustulosis
Thrombocytopenia
Taste disturbances
Leukocytoclastic vasculitis
Bundle branch block
Hyperpigmentation
Mood changes
Muscle pain
Muscle weakness
Parkinsonism
Sweating
Oedema
Abdominal pain
Lichenoid keratosis
Bronchospasm
Aggravation of existing asthma
Acute renal failure

Overdosage

It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

The following number will direct the caller to the relevant local centre (0844) 892 0111

Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Shelf Life and Storage

Storage requirements vary between brands - consult individual product literature.

Further Information

Last Full Review Date: March 2011

Reference Sources

British National Formulary, 61th Edition (2011) Pharmaceutical Press, London.

Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 8th edition (2008) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

Martindale: The Complete Drug Reference, 36th edition (2009) ed. Sweetman, S. Pharmaceutical Press, London.

Medications and Mothers' Milk, 14th Edition (2010) Hale,T. Hale Publishing, Amarillo, Texas.

Summary of Product Characteristics: Adizem-SR tablets. Napp Pharmaceuticals Ltd. Revised December 2010.
Summary of Product Characteristics: Adizem-SR capsules. Napp Pharmaceuticals Ltd. Revised December 2010.
Summary of Product Characteristics: Angitil SR/XL 90,120,180, 240 and 300 mg Prolonged Release capsules: Trinity-Chiesi Pharmaceuticals Ltd. Revised January 2011.
Summary of Product Characteristics: Calcicard CR tablets 90mg. IVAX Pharmaceuticals UK. Revised October 2010.
Summary of Product Characteristics: Calcicard CR tablets 120mg. IVAX Pharmaceuticals UK. Revised October 2010.
Summary of Product Characteristics: Dilcardia SR 60mg capsules. Generics (UK) Limited. Revised February 2010.
Summary of Product Characteristics: Dilcardia SR 90mg capsules. Generics (UK) Limited. Revised February 2010.
Summary of Product Characteristics: Dilcardia SR 120mg capsules. Generics (UK) Limited. Revised February 2010.
Summary of Product Characteristics: Dilzem SR 60, 90 and 120mg. Cephalon Ltd. Revised November 2010.
Summary of Product Characteristics: Tildiem Retard 90mg, Tildiem Retard 120mg. Sanofi Aventis. Revised May 2020.

Clinical Knowledge summaries (CKS)
Available at: https://www.cks.nhs.uk/hypertension_in_pregnancy#-467418
Last accessed: March 17, 2011

NAPOS: The Norwegian Porphyria Centre
Available at: https://www.drugs-porphyria.org/languages/UnitedKingdom/selsearch.php?l=gbr
Drug: Diltiazem. Last accessed: March 17, 2011

National Institute for Health and Clinical excellence (NICE) clinical guidance 107: Hypertension in pregnancy. Issue date August 2010
Available at: https://guidance.nice.org.uk/CG107
Last accessed: March 17, 2011.

UK Drugs in Lactation Advisory Service.
Available at: https://www.ukmicentral.nhs.uk/drugpreg/qrg_p1.asp
Last accessed: March 17, 2011

US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Diltiazem. Last revised: December 27, 2007
Last accessed: March 17, 2011