Many clients gain significant amounts of weight after a major trauma, particularly after a brain injury, spinal cord injury or amputation. 1, 2, 3.

There are many reasons for this, including reduced levels of physical activity and/or changes to body composition, both of which cause a person to burn fewer calories.  This means that unless someone is consciously reducing their food/calorie intake in order to compensate for this, then weight gain is likely to occur.  The weight gain is further compounded when someone is then prescribed one or more medications which have a side effect of increasing appetite, increasing food cravings and/or reducing metabolic rate even more.

Here are the top medications likely to contribute to weight gain:

1. Antipsychotic medication (4, 5, 6)

High risk of weight gain – clozapine, olanzapine, lithium

Medium risk of weight gain – quetiapine, risperidone

Low risk of weight gain – aripiprazole

Antipsychotics increase food cravings and stimulate the appetite (by blocking certain neurotransmitters in the brain).  This is why up to 70% of clients will gain weight on these medications.  The fastest weight gain tends to occur in the first six months.  These medications can also increase glucose levels and lipids in the blood, so regular blood tests are required to monitor this.

2.  Antidepressants (5, 7, 8)

High risk of weight gain – citalopram, amitriptyline

Medium risk of weight gain – mirtazapine, paroxetine, duloxetine

Low risk of weight gain – fluoxetine

Mixed reports on their impact on weight – escitalopram, venlafaxine, sertraline

The way in which antidepressants cause weight gain is poorly understood, but it’s thought to relate to how these medications impact the neurotransmitters and receptors in the brain which then increase appetite.

3.  Corticosteroids (5, 9, 10)

High risk of weight gain – cortisone, prednisolone, prednisone

Medium/low risk of weight gain – none

Up to 70% of clients report substantial weight gain on glucocorticoids, and this weight gain tends to be mostly around the abdominal region.  These medications stimulate appetite, increase preference for high-fat, high-calorie foods and reduce metabolic rate.  They also have a negative impact on glucose and lipid metabolism.  Weight gain tends to occur more in clients who are on these medications for over three months and/or those on doses over 5mg of prednisone (or equivalent).  Inhaled and single steroid injections have minimal impact on body weight, but repeat intra-articular injections in sensitive individuals can have a cumulative effect.

4.  Anticonvulsant/pain management medication (5, 9, 11, 12)

High risk of weight gain – valproic acid/valproate

Medium risk of weight gain – pregabalin, gabapentin

Low risk of weight gain or likely to cause weight LOSS –  lamotrigine, levetiracetam, phenytoin, topiramate, zonisamide

Mixed reports on the impact on weight – carbamazepine

These medications affect appetite regulation in the brain.  Valproates also have a negative impact on glucose and lipid metabolism.  The impact of pregabalin and gabapentin on weight may be more pronounced in patients with neuropathic pain, due to these clients needing a higher dose of medication.

5.  Diabetes medication/antihyperglycaemic agents (5, 9)

High risk of weight gain – gliclazide, pioglitazone, rosiglitazone, insulin (especially rapid-acting)

Medium risk of weight gain – repaglinide

Low risk of weight gain or likely to cause weight LOSS – metformin, SGLT2 inhibitors, acarbose, exenatide, liraglutide, sitagliptin, semaglutide, tirzepatide

The weight gain from these medications is linked to:  higher insulin levels, appetite stimulation due to fluctuations in blood glucose levels, eating to prevent or treat low blood glucose levels and improvements in glycosuria (which results in the body losing fewer calories).  A dietitian and diabetes nurse can help clients minimise weight gain by optimising blood glucose control, preventing episodes of hypoglycaemia and better matching the insulin dose to carbohydrate intake.

Additional information on the impact of liraglutide, semaglutide and tirzepatide on weight can be found at Pharmaceutical weight loss injections…do they work? and  Tirzepatide (Mounjaro) weight loss injections.

6.  Antihypertensives (5, 9)

High risk of weight gain – Atenolol

Medium risk of weight gain – Propranolol

Low risk of weight gain or likely to cause weight LOSS – furosemide, amlodipine, ramipril, hydrochlorothiazide, lisinopril, losartan

Weight gain from these medications is often due to a reduced metabolic rate and medication-induced fatigue.

What can be done?  Top 5 tips:

Carrying excess weight after a major trauma can put individuals at a higher risk of type 2 diabetes, cardiovascular disease, sleep apnoea, osteoarthritis and pain (both inflammatory and neuropathic), not to mention the negative effect it can have on someone’s self-esteem and ability to mobilise.

While medications may increase the risk of weight gain, steps can be taken to prevent this from happening and/or minimise the impact.  Here’s what can be done:

1. Encourage clients to monitor their weight, ideally before medication is started and then at least monthly after that.  The goal is to catch any problems early on.

2. Encourage clients to make healthier and lower calorie food choices as much as possible.

3. Encourage clients to be as physically active as possible.

4. Liaise with the GP, psychiatrist or consultant about whether there are other medications in the same category that could be used instead, preferably ones with a lesser impact on weight.

5. Refer to a dietitian if concerns are identified, particularly if weight gain exceeds 10% within 3-6 months.

To refer a client for a comprehensive assessment, recommendations and support around weight management issues (caused by medication or any other reason), contact Sheri Taylor, Dietitian with Specialist Nutrition Rehab at 0121 384 7087 or info@specialistnutritionrehab.co.uk.

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