Lantus

Injection (pen) · Sanofi
PRESCRIPTION MEDICINE

Lantus is a injection (pen) made by Sanofi that contains Insulin glargine 100 units/ml. Insulin glargine is a long-acting insulin: provides steady background insulin over 24 hours in diabetes.

Ingredient (salt)Amount
Insulin glargine100 units/ml

What it is used for

Provides steady background insulin over 24 hours in diabetes.

How it works

A long-acting (basal) insulin that releases slowly over about 24 hours to control background blood sugar.

How to take it

Inject once a day at the same time. Inject under the skin of the tummy, thigh or upper arm, rotating sites. Never share pens. Store spare pens in the fridge (not frozen); the pen in use keeps at room temperature for about 4 weeks.

Common side effects

  • Low blood sugar
  • Weight gain
  • Lumps or dents at injection sites if the same spot is used

Get medical help straight away if

Low blood sugar: shaking, sweating, hunger, confusion or fainting (take 15 g of sugar such as glucose or juice, then food)

Be careful

Can cause low sugar; check sugar levels as advised.

Other medicines and interactions

Alcohol, missed meals and exercise lower sugar further; beta blockers can hide warning signs. Steroids raise sugar. Pioglitazone with insulin can cause fluid build-up.

Pregnancy and breastfeeding

Insulin is the standard treatment for diabetes in pregnancy and is safe while breastfeeding; doses change and need close monitoring.

Same composition, other brands (1)

Basalog

Ask your doctor or pharmacist before switching brands.

Same ingredients, different strength or form

Toujeo

Common questions

What is Lantus?

Lantus is a injection (pen) by Sanofi containing Insulin glargine 100 units/ml.

What is Lantus used for?

Provides steady background insulin over 24 hours in diabetes.

How should I take Lantus?

Inject once a day at the same time. Inject under the skin of the tummy, thigh or upper arm, rotating sites. Never share pens. Store spare pens in the fridge (not frozen); the pen in use keeps at room temperature for about 4 weeks. Always follow the dose your doctor or the pack gives.

What are the side effects of Lantus?

Common side effects include: Low blood sugar, weight gain, lumps or dents at injection sites if the same spot is used. Get medical help straight away for: Low blood sugar: shaking, sweating, hunger, confusion or fainting (take 15 g of sugar such as glucose or juice, then food).

Does Lantus need a prescription?

Yes. In India it is a prescription (Schedule H) medicine, so a pharmacist should sell it only with a doctor's prescription.

Can I take Lantus in pregnancy or while breastfeeding?

Insulin is the standard treatment for diabetes in pregnancy and is safe while breastfeeding; doses change and need close monitoring.

What are the substitutes for Lantus?

Brands with the same composition: Basalog. Ask your doctor or pharmacist before switching.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Composition checked against pack details from large Indian online pharmacies. Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.