Tirzepatide with other medicines and health conditions

Pregnancy, trying to conceive and fertility

The two brands carry different pregnancy wording because they treat different conditions. Zepbound, for weight, should be stopped when pregnancy is recognized ^[1]. Mounjaro, for diabetes, may be used only if the benefit justifies the risk ^[2]. The tirzepatide labels do not set a waiting period before a planned pregnancy. Semaglutide labels do: they say to stop at least 2 months before ^[4]. If you are planning a pregnancy, set the timing with your prescriber.

Our sources contain no data on whether tirzepatide affects fertility. They do contain one fact that matters if you are not planning a pregnancy: tirzepatide can make birth control pills less reliable.

Birth control pills

Because tirzepatide delays stomach emptying, it may reduce how well oral hormonal contraceptives work. The Zepbound label says this delay is largest after the first dose and lessens over time ^[3]. It advises switching to a non-oral method, or adding a barrier method, for 4 weeks after starting and for 4 weeks after each dose increase ^[2]. Non-oral hormonal methods are not expected to be affected ^[2].

Breastfeeding

In a single-dose study of 11 breastfeeding women, tirzepatide in breast milk was undetectable or low, under 0.02% of the mother's dose. There are no data on effects in breastfed infants or on milk production ^[1]. The Medication Guide asks you to tell your provider if you are breastfeeding or plan to, because the drug may pass into milk ^[5].

Medicines the label names

• Insulin and sulfonylureas: the label tells prescribers to consider lowering these doses when tirzepatide starts, because low blood sugar becomes more likely ^[1]. In the diabetes trial, 10.3% of people also on a sulfonylurea had low blood sugar ^[1].
• Oral medicines: slower stomach emptying can change how pills are absorbed. The label advises monitoring for oral drugs that depend on precise blood levels to work ^[1].
• Birth control pills: backup method as described in the birth control section ^[2].
• Other tirzepatide or GLP-1 drugs: using Zepbound with another tirzepatide product or any GLP-1 receptor agonist is not recommended ^[3]. That includes taking Zepbound and Mounjaro together, or adding a semaglutide product.

Metformin, phentermine and ibuprofen are not named in the Zepbound drug interaction section ^[1]. That is not the same as the label saying they are fine together. Ask your prescriber and pharmacist to check your full medicine list. Switching between GLP-1s is covered on switching GLP-1s.

Blood pressure and the heart

Tirzepatide lowered blood pressure on average. In the Zepbound trial of adults without diabetes, systolic pressure fell 6.6 to 7.7 mmHg vs 1.0 on placebo, and diastolic fell 4.5 to 5.0 vs 0.8 ^[1]. Low blood pressure was reported in 1.6% vs 0.1% on placebo, and in 2.2% of people also taking blood pressure medicine ^[1]. Heart rate rose by 1 to 3 beats per minute on average ^[1]. Trial weight and waist results for the weight brand are on Zepbound results. Mounjaro is approved to reduce heart attack, stroke and cardiovascular death in high-risk adults with type 2 diabetes ^[2].

Kidneys and liver

The kidney warning is about fluid loss: vomiting and diarrhea can cause dehydration, which can lead to acute kidney injury, and the label lists acute kidney injury among its warnings ^[1]. No dose change is recommended for kidney or liver impairment ^[1]. Our sources contain no tirzepatide data on liver enzymes or fatty liver. Zepbound is not approved for fatty liver disease; the Wegovy injection is approved for one form, MASH with moderate to advanced fibrosis ^[4].

Thyroid

The boxed warning covers thyroid C-cell tumors seen in rats; whether this happens in people is unknown. Tirzepatide must not be used with a personal or family history of medullary thyroid carcinoma or MEN 2 ^[1]. Report a neck lump, trouble swallowing, shortness of breath or lasting hoarseness ^[1]. Our sources do not address hypothyroidism specifically; if you take thyroid pills, ask whether the oral-medicine monitoring advice applies to you.

Diabetes, PCOS, menopause and inflammation

Tirzepatide is used for type 2 diabetes under the Mounjaro brand, approved for blood sugar control from age 10 ^[2]. In the Zepbound trial of adults with type 2 diabetes, HbA1c fell 2.1 points vs 0.5 on placebo ^[1]. New diabetes is not among the label's warnings ^[1]. For people without diabetes, the main safety data are the Zepbound trials; see tirzepatide side effects.

Insulin resistance, PCOS, menopause symptoms and inflammation are not approved uses, and our sources hold no tirzepatide trial data on them. On the hormone question: the label classes tirzepatide as a GIP and GLP-1 receptor agonist that acts on the targets of the body's own GIP and GLP-1 ^[1]. It is not a steroid or a sex hormone.

Surgery and procedures

Food or liquid has entered the lungs of some people on tirzepatide during general anesthesia or deep sedation. The label sets no stop interval before a procedure; it tells patients to inform their providers that they take it before any planned procedure ^[1]. Timing around surgery is on stopping tirzepatide.

Brand pages: Zepbound interactions and Mounjaro interactions. Overview: tirzepatide.