The short answer: Mounjaro and high blood pressure
Mounjaro is not automatically ruled out if you have high blood pressure, and in most people it lowers blood pressure rather than raising it. In a large trial of 2,539 people over 72 weeks, systolic pressure fell by about 6.8 mmHg more than with placebo [2]. The catch is for people already on blood pressure tablets: as weight falls, pressure can fall enough to cause dizziness in some people, and the prescriber who looks after your blood pressure medicines decides whether anything needs adjusting [2,5]. Vomiting or diarrhoea adds a kidney concern with some of these medicines [1,6].
This article separates what the official drug label says from what trials found, and gives you a table for each class of blood pressure medicine: what to watch and what to tell your doctor. It also lists the home readings to bring to a review, so the decision rests on your own numbers rather than guesswork.
What the label says and what trials found
First, two kinds of information need to stay apart. The official label is the safety summary a regulator accepts, while trials report what happened to groups of people followed for a set time. Both matter, but they carry different weight and should not be blended.
From the US prescribing information, last revised in August 2026, two items matter here. The first is a small rise in heart rate: the mean increase was 2 to 4 beats per minute, against about 1 with placebo [1]. The second is postmarketing reports of acute kidney injury in people taking GLP-1 receptor agonists, Mounjaro included, mostly in people whose stomach and bowel side effects led to dehydration, and in some cases dialysis was needed [1]. The label says kidney function should be monitored in people who report reactions that could lead to volume depletion [1]. The US label can differ in detail from the leaflet inside your own box, so read yours and ask your pharmacist.
The fall in blood pressure itself, dizziness on standing, and the share of people who reach a normal reading are trial results, not label statements [2,3,4]. The large trial was funded by the manufacturer, and it has limits: many participants started with near-normal pressure, and people with very high pressure were excluded [2].
For the wider picture of how weekly injectable medicines differ and how they work, see the GLP-1 medicines guide.
Why pressure falls as weight falls
In the large trial of 2,539 people, mean starting pressure was 123.3 over 79.5, so most participants did not have very high pressure; only 32.3% had a history of hypertension and 29.9% were taking a blood pressure medicine [2]. After 72 weeks systolic pressure fell by 8.1 mmHg on Mounjaro against 1.3 on placebo, a difference of 6.8, and diastolic fell by 5.3 against 1.0, a difference of 4.2 [2].
Most of the fall came in the first 24 weeks and then levelled off. At week 24 the systolic drop was about 7.8, 8.3 and 8.5 mmHg for the 5, 10 and 15 mg doses, against 1.6 on placebo [2]. By the end, 58.0% had a normal reading compared with 35.2% on placebo [2].
Weight is the main driver: a mediation analysis estimated that weight loss explained about 68% of the systolic fall and 71% of the diastolic fall [2]. In a substudy that measured pressure over 24 hours in 494 participants, weight change explained about 70% of the systolic change, although that estimate is imprecise [3].
This trial is SURMOUNT-1: adults with obesity (BMI 30 or more, or 27 or more with a weight-related complication) and without diabetes received once-weekly tirzepatide or placebo for 72 weeks. Mean weight change at week 72 was a fall of 15.0%, 19.5% and 20.9% at the 5, 10 and 15 mg doses, against 3.1% with placebo [7]. The SURPASS programme in people with type 2 diabetes found that the systolic reduction was primarily mediated through weight loss, and that reductions were similar whether or not people were taking blood pressure medicines at baseline [8]. The largest reductions were in people whose baseline systolic pressure was above 140 mmHg, while those in the lowest baseline group (below 122 mmHg) showed no further decrease [8]. The WHO also lists being overweight or obese as a risk factor for hypertension [10].
The practical point is that a blood pressure medicine that suited you at a higher weight can become stronger than you need after months of weight loss. That is not a fault in the medicine; it is a possible effect of weight loss, and your doctor needs to know so the treatment can be reassessed. For the full plan on food, activity and tracking, see the weight-loss plan for high blood pressure.
Dizziness and low pressure: the real numbers
Blood pressure-related events occurred in 6.8% of people on Mounjaro against 3.3% on placebo [2]. In detail: dizziness 4.6% against 2.3%, hypotension 1.0% against none, orthostatic hypotension (a drop on standing) 0.6% against none, fainting 0.5% against 0.8%, and near-fainting 0.5% against none [2]. Severe events occurred in only 4 of 1,896 participants (0.2%), and no severe orthostatic hypotension was reported [2].
A pooled analysis of 32 randomised trials with 47,332 participants found that hypotension-related events with tirzepatide were more frequent, with a relative risk of 2.45 (95% CI 1.35 to 4.45), rising at higher doses, while hypertension-related events were less frequent, with a relative risk of 0.40 [4]. The overall picture is that it is relatively uncommon but real. The authors suggest that treatment decisions take baseline blood pressure into account [4].
The NHS defines low blood pressure as a reading below 90/60 mmHg. Common symptoms are lightheadedness or dizziness, feeling sick, blurred vision, weakness, confusion and fainting, and dizziness can come on when you stand up quickly [5]. The number alone is not the whole story: one person with 100/65 and no symptoms is very different from another with the same reading who feels faint and falls.
If dizziness keeps recurring, or you faint or feel you are about to, tell your doctor. For fainting, chest pain or being unable to keep fluids down, seek urgent medical care. Changing any medicine is your prescriber's decision, not yours.
Blood pressure medicine classes: what to watch and what to say
This table is for preparing a review visit. It does not replace your doctor's decision and contains no dose changes. In the large blood pressure trial, 29.9% took a blood pressure medicine: ACE inhibitors 8.0%, angiotensin receptor blockers 14.9%, diuretics 2.0% and calcium channel blockers 1.1%. Reliable data on medicine adjustments were not collected, so their effect on pressure cannot be judged [2]. The NHS notes that you may need more than one medicine to keep your blood pressure under control, and that the medicine recommended depends on how high your pressure is, your age and your ethnicity [11].
Class: ACE inhibitors (names usually end in "pril"). Watch: dizziness, how much urine you pass, and any vomiting or diarrhoea, because dehydration can strain the kidneys with this class [6]. Tell your doctor: how many episodes of vomiting or diarrhoea you had, your sitting and standing readings, and the date of your last kidney blood test.
Class: angiotensin receptor blockers, or ARBs (names usually end in "sartan"). Watch: the same dehydration and kidney point, and dizziness on standing [6]. Tell your doctor: the same details as above, and whether another blood pressure medicine is combined in the same tablet.
Class: diuretics, the "water tablets" that increase urine and fluid loss. Watch: thirst, passing little urine and dizziness, because a diuretic can add to dehydration during vomiting and diarrhoea [6]. Tell your doctor: what time of day you take it and whether you are passing more urine than usual.
Class: calcium channel blockers. Watch: dizziness on standing and lightheadedness as weight falls [2,5]. Tell your doctor: what time of day the symptoms come and your readings at that moment.
Class: beta blockers. Watch: pulse and any sense of palpitations, because Mounjaro raises heart rate slightly, so a pulse reading needs interpreting alongside this medicine [1]. Tell your doctor: your resting pulse and the pulse at the time of symptoms.
Class: combination tablets (more than one active ingredient in one tablet). Watch: the combined effect of the points above. Tell your doctor: the full name on the box, not just "my blood pressure tablet" [2].
Dehydration and kidneys with blood pressure medicines
Vomiting and diarrhoea are well-known stomach and bowel effects of Mounjaro, and they can lead to dehydration. The label itself links acute kidney injury to volume depletion from those effects [1]. The Scottish leaflet notes that ACE inhibitors and angiotensin receptor blockers can stop the kidneys working properly when you are dehydrated, and that diuretics can worsen dehydration [6].
Health services in Scotland publish a patient leaflet on "sick days". It lists these classes, along with anti-inflammatory painkillers such as ibuprofen, as medicines whose handling your clinician agrees with you in advance for an illness that dehydrates, meaning two or more episodes of vomiting or diarrhoea, or fever and sweats [6]. The leaflet says the plan is agreed with a healthcare professional before illness strikes, and that if it is unclear whether the guidance applies to you, you should ask [6].
So what is asked of you is to ask your doctor beforehand: is there a written sick-day plan for me, and who do I call? And do not decide alone. During an illness, note how many times you vomited or had diarrhoea, how much fluid you can keep down, how much urine you passed, and your blood pressure and pulse readings.
The full detail on kidneys, what to tell the prescriber, and when kidney function is checked is in the Mounjaro, kidneys and dehydration article, so it is not repeated here.
Heart rate: the small rise on the label
The label says the mean rise in heart rate in the placebo-controlled trials was 2 to 4 beats per minute, against about 1 with placebo [1]. A rise of 15 beats per minute or more from baseline (sinus tachycardia) occurred in 4.3% on placebo, 4.6% on 5 mg, 5.9% on 10 mg and 10% on 15 mg. The label states that the clinical relevance is uncertain [1].
The 24-hour monitoring substudy within the large trial found a heart-rate increase against placebo of 2.1, 2.3 and 5.4 beats per minute at the 5, 10 and 15 mg doses [3]. So the rise grows with the higher dose, but its average size is small.
These are averages. Some people will notice palpitations or a heart that beats faster than usual. None of these sources gives a number that lets you judge on your own whether your pulse is "dangerous" or "fine". What we can say is: record your pulse at rest in the morning and evening, record it again whenever you feel palpitations, and bring the log to your doctor. Chest pain, fainting or sudden breathlessness are not a routine review matter; they call for urgent care.
Worth knowing: this clinic does not provide cardiology. If you have a known rhythm problem or follow up with a cardiologist, keep their results to hand at your review and we will help coordinate the information.
The home readings to bring to a review
A sound decision needs a wider picture than one reading in the clinic. What we usually ask for is a log covering a week before the visit: two readings in the morning and two in the evening, after about 5 minutes of rest sitting with your back supported, with your pulse recorded each time. This is a practical method used in our clinic, not a numeric cut-off attributed to any particular source. For reference, the NHS describes high blood pressure as 140/90 or higher when checked by a healthcare professional and 135/85 or higher at home, and notes that it does not usually cause any symptoms [9]. The WHO says diagnosis needs readings on two different days, and that hypertension is often silent [10]. That is why a single reading is not enough.
If you feel dizzy on standing, add a standing reading one or two minutes after you get up, since a drop in pressure on standing is a recognised cause of dizziness [5]. Note the time the dizziness happened and what you were doing.
Write simple notes beside each reading: did you take your blood pressure medicines at the usual time, was there vomiting or diarrhoea, how much fluid did you drink, and was this the day of your weekly dose or one or two days after. Bring your weekly weight too, because the link between weight loss and falling pressure is the foundation of the whole question [2].
Also bring a list of every medicine with its full name from the box, your latest kidney blood test if you have one, and the monitor itself so its accuracy can be checked. For the full method of tracking, see the weight-loss plan for high blood pressure. An InBody scan is also available with us to follow your muscle share as weight comes down.
Are any medicines banned? The more useful question
Many people ask about "banned medicines". That phrasing is not accurate. The sources we relied on do not give a banned list of blood pressure medicines to use with Mounjaro. What they give is review points: which medicine, at what dose, in which situation.
The clearest situation is dehydration. ACE inhibitors, angiotensin receptor blockers and diuretics, along with anti-inflammatory painkillers such as ibuprofen, all sit in sick-day plans because dehydration with them can harm the kidneys [6]. So if you buy a painkiller without a prescription while you have vomiting or diarrhoea, ask the pharmacist or doctor first.
Another situation is repeated dizziness on one or more blood pressure medicines [2,5]. The answer there is not to drop a medicine on your own; it is to give the doctor your readings so they can decide.
Then there are other medicines: if you take diabetes tablets or insulin alongside Mounjaro, that decision is also your doctor's. This article stays with blood pressure medicines and gives no guidance on others.
Reviewing blood pressure medicines alongside Mounjaro at La Rose
Weight management and Mounjaro follow-up are available at two branches: Maadi, and Fifth Settlement at CMC Medical Mall on Wednesdays from 3:30 pm. Details for each branch are in Mounjaro follow-up in Maadi and Mounjaro follow-up in Fifth Settlement.
If you need an internal medicine review linked to blood pressure and medicines, internal medicine with Dr Mohab Ashraf Fouad is in Maadi only. An InBody scan is also available to follow body composition as weight comes down.
The clinic does not provide cardiology or nephrology. If your blood pressure medicine is managed by a cardiologist or kidney doctor, that doctor decides about changes, and we help build a full picture of readings, weight and symptoms so the decision rests on data.
What to bring: a week of readings, your medicine list with names from the boxes, your latest kidney tests if you have them, and notes on vomiting, diarrhoea and dizziness. Book your appointment on the booking page [2,5].
