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Cough, colds and diabetes

By Donna Itzstein, Diabetes Qld Pharmacist

Pain,  infection and generally feeling unwell may raise blood glucose levels in those living with diabetes. Short illnesses during the colder months may not require changes in diabetes management, however, long-term conditions leading to a change in medications such as steroids may require a treatment change. Do your patients ask you how to manage their coughs and colds? This may assist you with your answers.

Pharmacy preparations may be in liquid, tablet, nasal sprays or lozenge form. They contain a variety of ingredients which may affect glucose levels, so here are some things to consider:

Decongestants pseudoephedrine and phenylephrine will raise blood glucose levels. While no direct studies confirm this, older studies with ephedrine and with mice models support what happens in humans. (1) (2) The Therapeutic goods administration website product information suggests caution for use in people living with diabetes. (3) These oral medications may also increase blood pressure. Blood pressure management is an important aspect of diabetes and cardiovascular management.

Other ingredients such as guaiphenesin, dextromethorphan, ivy leaf, pholcodine will not directly affect blood glucose levels. Mixtures may contain sugar or honey, natural sugar sources.  Consider how much sugar is in a dose in relation to the total carbohydrates in a person’s usual daily consumption. This is often minimal. Many of the currently available mixtures and lozenges are sugar free (4).

Some tablets may include analgesics for pain and fever.  Ibuprofen may not be appropriate if your patient has gastrointestinal tract conditions. Ibuprofen interacts with medications that act on the kidney. Ibuprofen retains fluid raising blood pressure and adds strain on the heart. Paracetamol is considered a milder analgesic; however, patients may take paracetamol in other formulations such as for arthritis. The total daily amount exceeding 4 grams may be hepatoxic (5).

Herbal preparations in liquid or lozenge formulation will not directly improve symptoms. They assist in reducing the duration of illness and may have a placebo effect. All ingredients whether they be chemical or herbal must be considered. All preparations have the ability to have serious interactions. Encourage your patients to check with their Pharmacist before using any preparation (4).

Nasal sprays work directly on the nasal cells with very little systemic absorption. This is due to the small amount of medication required for a direct local effect. Nasal sprays will have little or no effect on blood glucose levels. Nasal sprays may contain decongestants such as oxymetazoline, and Ipratropium in Atrovent which can be used for 3-5 days. Regular ongoing use is not recommended due to rebound congestion.  Hay fever symptoms may require use of steroid sprays for short or long periods of time (5).  Saline sprays are an option for congestion with or without other sprays or oral medications. Chest rubs and inhalations or nasal rinses are useful to clear sinus congestion and have no impact on glucose levels.

Messages when discussing cough and cold remedies:

  • Consider how long they will be taking this medicine. Short term use may not be an issue.
  • For preparations containing sugar or honey will the amount ingested make a big difference to blood glucose levels? For example you may like to ask your patient how many lozenges a day they are having and if they have noticed a difference to the glucose levels.
  • Are there alternatives which have little affect on blood glucose, such as nasal sprays.
  • Consider the analgesic contained in the preparation. Does it interact with the persons other conditions or medications? Ask your patient to consider consulting their local pharmacist regarding an appropriate remedy.
  • If your patient is not fluid restricted request they drink extra water. High blood glucose spills over into the urine and takes water with it, dehydrating the body.
  • For unmedicated options consider saline nasal sprays or rinses, heat rubs and inhalations.
  • Consider other medical conditions, to asses also kidney and liver function.


For information on this article or any general enquiries please contact Diabetes Queensland or Diabetes New South Wales.


  1. The glycemic responses to selected sympathomimetics in the normal and goldthioglucose mouse . Sandage, B W. Purdue University : Proquest dissertations, 1981.
  2. Comparing hemodynamic and glycemic response to local anesthesia with epinephrine and without epinephrine in patients undergoing tooth extractions. Kaur, P, et al. 2, July 2016, National Journal of Maxillofacial surgery, Vol. 7, pp. 166-172.
  3. Therapeutic goods administration. Core pseudoephedrine product information. Theraeutic goods administration. [Online] [Cited: August 16th, 2019.] https//www.tga.gov/sites/default/files/otc-template-pi-pseudoephedrine.rtf.
  4. MIMS Australia. Mims online. North Sydney  : MIMS Australia, 2019.
  5. Therapeutic Guidelines Limited. Therapeutic Guidelines . [eTG] West Melbourne : Therapeutic Guidelines Ltd, June 2019.